I think you may be a bit confused wrt mast bending. The deck step is a point of rotation that makes it harder to put a bend into a mast (think: load up the back stay and the mast tilts back). To bend a deck stepped mast mast you use baby forestays, fractional rig or forward mounted lower shrouds. In a keel stepped mast these serve to control pumping.
They actually set the mast bend in both setups. The mast pumps when the rigging is too loose for the wind conditions. Deck stepped masts need much tighter rigging so this usually never occurs. Keel stepped masts can have looser rigging because the mast deck interface gives it a lot of stiffness so the rigging doesn’t need to stress the boat by being so tight.
Thank you for your video. An area you brushed over and in my opinion incorrectly. I am referring to your comment that to cruisers are not racers and "cruisers do not care about adjusting everything". Although, cruiser should most certainly care and always look to race techniques to get the highest proficiency from whatever rig or hull type you operate. I have rarely seen seen two sailing vessels get together and not want to tweak every ounce of performance from there vessel. In my opinion cruisers should look to there racing compatriots for proven examples for sail trim and performance. Jibsheet lead, backstay tension, traveler, luff tension, Sail draft, camber, mainsheet, halyard tension and so forth. Being able to adjust and understand the performance capabilities of your vessel is paramount to good seamanship.
Hundred percent agree with this. I work in the traditional vessel world of sail training ships, gaffers and square riggers and just because the vessels are 200 years old in design doesn't mean we don't take pride in squeezing every ounce of performance out of them when the right circumstances present. Working aboard the three master L'Hermione if the captain came on deck and the yards were braced a point or point and a half off of where they should have been to get maximum drive for the given wind angle he would look at the watch leader and make a remark, and the crew would be scrambling around to adjust nearly 40000 square feet of sail to the inch to make sure that every sail was working at it's utmost efficiency. Those vessels were complicated machines and some of them performed extremely well for their day, but not if they were sailed sloppy. The good captains and mates of those days were always trimming and watching their rig closely no matter the conditions. I think having the instinct to be constantly alert and looking at your rig and adjusting (which some might think is a "racer attitude"), and to know exactly how the boat will perform on every point of sail in every condition is just the basis of seamanship. My partner and I have a Heavy displacement cruising boat now and I've carried my experience forward. You don't need to be in "race mode" every second but the vigilance and intimate knowledge of your vessels trim that comes from the racing side of things will benefit cruisers if they need to get themselves out of sticky situations, eg. Beating off a lee shore following an engine failure, how to drive the boat safely downwind in a blow, or how to heave-to well, knowing exactly how much sail to set and trim it. Rigging doctor puts out lots of good stuff, but @Bo Jangles is right on this one.
I agree. Put two sailing boats in the same body of water, on the same course and there is automatically a race happening even if they are totally miss-matched. I used to have a Ruffian 23 1/4 tonner which I had great fun with, passing much larger boats
I think the point should be emphasized that if you are deck stepped, you can still cross oceans with a single spreader. Many, many designs do including some of the most popular offshore boats ever created like the Westsail 32 and the entire Hans Christian line up. Also should be noted that if a keel step mast fails entirely it can completely can open the coachroof when it levers over. We have seen it firsthand. Good video otherwise, just be careful when making statements not sound like hard fast rules for the people that know no better.
@@corviswood its an issue with any boat with a keel stepped mast if the rig fails and does not break at the lowest spreader generally cause by a failing chainplate
Any racing boat I have been on had a keel stepped mast and my 1/2 tonner is keel stepped too. The reason is, when the back stay is hauled on, the load is transferred to the keel and not to the coach roof which can give way or deform. Cruisers like deck stepped masts as, the constant leeks through the deck are not a problem. I thing the narrator needs to re-think some of his points
Almost all deck stepped masts have compression posts (with some exceptions, Albin Express comes to mind first). But yes, racing boats actually do have keel stepped masts for a reason. Simplest answer is you can get same stiffness with thinner mast, which is good for weight saving and less windage. Long answer is trimmability. With Keel stepped mast, you can adjust prebend and forestay tension by moving mast step fore-aft (and/or adjusting fore-aft positions in the mast partners). But say the partners is not adjusted, then moving keel stepped mast aft on the mast step, you create more prebend and less forestay tension. Second thing to consider is sidebend caracteristics. For heavy wind you want mast top to bend leeward, creating windward sidebend in mid section. This helps to open the slot between jib and main. And considering the deck stepped mast adds stiffness for the lower part of the mast, this will be helpful in creating windward sidebend.
Every racing boat I've sailed has had a keel-stepped mast and the cruisers have had deck-stepped with compression posts. I think stopping coach-roof leaks is one of the motivators for the latter.
Leaks like that are easy to prevent. It does however require some periodic maintenance and inspection. But not to the point where that is an issue. I had a new boat with that leak. I only knew because the bilge kept getting wet. I complained. He said, as if I were a dolt, It’s a boat. I finally tasted it. Fresh water. I went topside, adjusted and lubricated the seal. Then climbed the mast and sealed found inspection plates left off the mast so that rain would get into the mast. Made the mast as tight as I thought necessary and appropriate. Bone dry bilge and sump. Diverting water is not rocket science. I don’t consider that in my decision about mast stepping. Or internal space.
This is just like listen to one football supporter trying to explain a supporter of the other team, why they’re team is the best. You are so totally in love with your own choices. That does not only include the keel stepped mast.
Big advantage of a keel-stepped mast is that when there is no load it is self-supporting even with the shrouds off - comes in mighty handy when stepping/unstepping the mast (takes a lot of stress off the process).
The primary question between deck stepped and keel stepped masts is structural. The forces on a mast are compressive in nature and not bendyness. Well maintained rigging keeps the mast in compression, which can equal the weight of the boat or more in a stiff breeze. So the actual question is; do you want the compression force on the deck or the more solid keel? In my experience, no amount of deck reinforcement including bulkheads or compression posts, can keep the boat from deformation with a deck stepped mast. In addition, keel stepped masts stay in tune longer simply because of this deformation of the hull and deck structure. Any offshore passage-maker will have a keel stepped mast, deck stepped masts are for daysailers.
@@jonathanwetherell3609 No, because all the loading is converted to downward pressure by the rigging. The mast extrusion, if designed properly, takes any side loading between the rigging attachment points, but the primary loading is downward force at the mast step, sometimes up to twice the weight of the boat.
@@oceannavagator The UDL of the main sail imparts a bending moment to the mast, which is a beam. The beam is supported by the rigging, which imparts both a compressive and support loading at 90° to the mast/beam axis. The deck mounted mast has axial and a load at 90° at this point. The keel mounted mast has both bending moment and a load at 90° at this plane.
@@jonathanwetherell3609 Look, I get that the stick has a bending moment but that force is resisted by the rigging if in proper condition transfers the force to the mast step downward and the side stays upward. Because the mast is in column, any bending moment now heels the boat over. Any dismasting that I have ever seen that wasn't a rigging failure (meaning that all the rigging was in place) was a result of the mast coming out of column, ie going S shaped between attachment points which slacks the windward stays and allows the stick to fail. The extrusion has to be strong enough to resist the pressure that the stays impart on it, When deck stepped, the cabin top will flex downward, slacking the stays, allowing the mast to come out of column. Some boats are so bad that when going to weather you can't even open the forward cabin door due to the distortion in the main bulkhead.
There is one extra consideration in my opinion. A deck stepped mast can be lowered without use of a crane. Yes I know it's a pain in the backside but sometimes you really want to be on the other side of that bridge.
I used to own a Soveral 36 racer/cruiser, hull #9. Back on the day it was the only boat Ted Turners team couldn't catch...its very fast and its keel stepped!
On our new boat which is a three masted Schooner we have deck stepped all the masts, whereas the original design had all three keel stepped. We find that with the deck stepped masts we don't have any of the original designs issues with water ingress when shipping green in heavy weather.
🤔 Deck-steep mast: Another aspect of a deck-step mast is the ability to step & unstep the mast without crane 🏗 support for canal and inland travel in areas of low bridges. Every time the mast is lowered, the rigging presents an opportunity for close inspection without going aloft. If a breakage occurs one is not left with a potentially jagged mast in the cabin and water pouring in. A “D-S-M” for a larger boat, lacking a compression post, needs to be designed with lateral arches to transfer the load to the frames, and then on down to the keel. I’ve wondered if a “clam shell” clamp on the cabin top with a pivoting shoe might aid in mast tuning.
When we rebuild our Alberg 30 (our next project) I’m going to be putting a tabernacle on the deck stepped mast to allow for just this very thing. The ability to raise and lower the mast will be invaluable while cruising into areas that we were simply kept out of by a low bridge.
@@RiggingDoctor We devised a mast lowering arrangement for a West Wight Potter 19 which was quite safe, allowing us to raise & lower the mast while actually underway (as long as the surface weren’t too rough ….. otherwise it was a dockside evolution). This allowed us to slip under low bridges and have the mast back up and tuned before reaching the next lake (Florida & Gulf sailors). Ever since then I’ve been considering how I could achieve the same arrangement on a larger boat where the weights are higher. This, while saving time & support fees is mostly an issue of self reliance and autonomy for us. I really appreciate the videos you uploaded on Dyneema. It seems like a no-brainer to me. I worked in the Nuclear Industry for forty years. We used to lift 110 Ton Spent Nuclear Fuel Casks with very heavy, and dirty 🤣 wire and shackles (about an 80# rig per side). Well Kevlar slings came into favor (light as a feather, very pliable and much stronger) ……… the wire ropes were quickly retired. I think that other advantages of Dyneema is that by having less weight aloft, in addition to stability, it will present less of a risk of injury from the standing rigging upon failure compared to wire or worse rod rigging. It is also light and pliable enough to even have spares onboard for longer blue water adventures to remote places. Herbie, Thanks so much for your insights on rigging & cruising pointers.
great info.. Even cruising sailors, well me, like to be able to bend the mast. To depower the main primarily. Crank on that backstay and push the mid mast forward and you dont need to reef nearly as early.
If you want a lot of mast bend, normally you design that into the mast and rig by doing things like going to a fractional rig with the mast tapered above the forestay attachment. You can do that with a keel or deck stepped mast. However. deck stepped masts generally have a stiffer spar design (larger and heavier) than keel stepped designs. You can still bend a deck stepped spar particularly if you go with a fractional rig and tapered mast, but it always takes more force that with the lighter keel stepped spar. A big advantage of a deck stepped spar if you sail in a place where you haul out annually is that it takes less time and is thus cheaper to step and unstep deck stepped spars that keel stepped spars.
SW, you completely forgot to mention the very large compressive forces that rigging imposes upon the mast that are transferred to the mast step, either at the deck or at the keel. The person who designs the hull has to put a whole lot of strength and weight of materials to support that compressive load, which may be on the order of many tons [or tonnes if you are a metric person]. The decision about where you put those compressive forces has a lot to say about how the boat itself is built.
So it seems that it is the spreader attachment that introduces extra stresses & weakness in the mast - is that correct ? ? & if so how to design a rig that does not need spreaders & can perform at least as well?
Great video. One thing: Many, I believe most, racing boats of all sizes have a keel stepped mast. It is preferable to lead the loads into the keel.The touchpoint at the deck has many advantages. You can even use it to control mast bend precisely. In a 420 for example, you control with some simple removable pieces of wood how much bend you want to apply in different wind conditions. Most biggers boat also have keel stepped. As you said, rigging can be lighter. As an exception many French offshore boats have deck stepped. I believe even as a rule. They take dismastings for granted and see the hole in the boat as the bigger problem. If your mast goes overboard cleanly, you still have the deck step as a jury rig attachment point.
For a proper offshore boat whether it is a cruiser or a racer, I will choose deck-stepped every time for safety and convenience reasons. If something bad happens to your rig, with a deck stepped mast, you stand a good chance of keeping the boat watertight which should be your top priority, whereas if you have a keel stepped mast, the chances are that there will be a big hole to plug or even worse that the mast comes off damaging the roof! Also IMHO having to care for extra diagonals is a mere inconvenience compared to the constant battle of keeping the mast / roof junction watertight on a keel-stepped boat. French offshore racing classes (IMOCA and mini 6.50) have prohibited keel-stepped masts for safety reasons. Finally it isn't uncommon for racing boats to have keel-stepped mast because it lets them use a lighter mast section with a smaller inertia thus they can tweak its bending more by tuning the tension in the runners, the backstay and the checkstays. With great powers come great responsibilities as if you invert the mast with the checkstays, chances are that it will come down.
Very well said. The hole in the deck is always a bother to us. I need to freshen the seal yearly, but thankfully the mast is in my shower so any leaks are not the end of the world!
Great video, thanks for sharing. One topic not covered is that of water ingress. I have yet to come across a keel stepped mast that does not leak a little water. Not a catastrophe but can cause ongoing problems with mould and moisture. Another aspect is whether it is better to have a mast completely fall over board and can be cut free (deck stepped) or a snapped mast still attached to the boat and hard to cut free (but not punching holes in the hull). I like the way you say that these are all really, really bad situations. the question is, which is worse.
Why would you cut free the deck stepped mast that fall overboard ? Depends of course on the size of the boat and conditions, but it is doable to just lift it on board ( I lost a mast that way on 28 ft boat, needed help from guys from the club with a dingy, to de-rig the mast in the water of sails, but then we just piled everything on board and motored home )
I thought there was a lot of good information here even though in the beginning I think when you first described the primary diff between the two and then went into the spaghetti lengths and bendability you should have mentioned immediately that the deck “interface” acts as a segment creator so that comparing the two WITH NO SPREADERS the deck stepped mass has one segment while the keel stepped mast has two segments. Then go into spreaders. You don’t mention that a keel stepped mast deck interface is a length shortener. Not too big a deal. I’m irritated when writers go off like that because I am an OCD reader. I hang on every word the writer says so long as I’m learning. And it was immediately clear to me that you met the bill. So I hung in there. There is so very much to say about this subject but it all comes down for me (who as a sailor did not spend any time in marinas drinking with my business friends. I’ve been in some very unfriendly weather and I have met half the famous ship wrecked sailor-authors. The serious sailing community is very egalitarian.). I taught. Computer science. When a subject is nuanced enough it is useful to teach in a series of understandable white lies. Then when the students have more understanding tools, set the record straight. For me: I would never own a boat that was not keel stepped. There are no interior decorating negatives. It’s not even a Bauhaus function over form aesthetic. You want smaller spaces below. It’s not a condo in Boca Raton. It’s a boat. You want multiple function purposes spaces. You need hand holds. It’s a sailboat. You will need to cook and sleep and shit in 60kt winds with crashing packed 40 foot walls of water. IF you’re a sailor and not a rich guy with a boat. When I was 13 I read John Masefield’s Sea Fever. I was transfixed. It was for be what Alice in Wonderland or Harry Potter were to gazillions of normal people! I kept reading it. I memorized it. I knew that someday I would sail. Despite growing up away from sailing and the water and having a father who was not a sailor and had no interest in it. He did take us out on a motorboat two times. I was irritated by the idea of the noise and the fumes polluting the Chesapeake Bay in off season. And I saw sailboats heeled over catching the wind and silently accelerating till they got a bow wake and then seemed to stop accelerating and I was being drowned in data points, trying to reverse engineer all the effects I was noticing into the principles and the control surfaces. When I first sailed it was after I purchased my first sailboat. 46 Beneteau. Everyone said I was nuts. I was 50. Just retired. Asked my wife if she would mind if I bought a sailboat and sailed away and Dre could come and visit me from time to time and sometimes depending where I was and when, I could fly back for a while. She said, You betcha! At the time I was not sure if this response was a good thing or a bad thing but I wasn’t going to look a gift horse in the mouth. At worst I’d have to pay on Tuesday for my hamburger today. As Norman Maclean said, I am haunted by waters. And beams. And moment arms. All good technology at first seems like magic. It’s indistinguishable.
The only tweeking ii do when cruising (50,000 miles) is the rum glass .My last trip up to Tonga in 55 ft Warwick MS we averaged 9 kts , not to bad for a 30 ton yacht .
A major problem.is we have racing rigging on cruising boats. The spreaders and stays on mty beneteay lu 44 has the mast chainplates on the edge of the deck and heavy mast section . Big wide spreaders. I see similar size cruising yachts with lighter sections and chain plates well away from the edge of the deck. Not as much leverage and requiring tighter shrouds to give same supports. Ive also not seen a mast break at the deck mainly at the upper stay. I also have twin backstays. Only thing i will add will be an inner forestay fir a smaller headsail.and to add support to lower mast section.
Yep, people want the racing style but forget that the lifespan of a race boat is the race, the lifespan of a private yacht is supposed to be a lifetime.
@@RiggingDoctor you hot that right. Most modern cruising. Boats are lacking in requirements for cruising. Fair weather sailors. I think the only yacht in the club with wider spreaders is the nautor swan 54 in the pen opposite me. Also got solid stainless rigging but not in mast main which is good. Down below is magnificent but i would feel guilty cruising in her. Beside i would need buckets of dollars to keep her in good condition and use her a lot. My first yacht i bought hull and decks and fitted out 40 years ago and is still sailing. I used lots of quality teak. Now im happy with less timber.. best regards and happy sailing
Very informative... Is it fair to summarize that a typical racing rig is more complicated than a cruising rig, gives you more options, at the cost of requiring more ATTENTION, and making more frequent rig adjustments?
Well I am no expert and maybe I am entirely wrong but as I see it, the keel stepped mast would really only have limitations for adjustment because those movements would be made from the ends, the point of compression at the bottom and at the top of the mast, so to allow the movement to take place, the hole through the cabin would have to be large to accommodate the movement of the mast itself, which seems counterproductive. But as far as bendy-ness goes, I can see no reason why a deck stepped would be more bendy or substantially less stiff. If we are talking about masts of the same height, remember that the keel stepped mast is longer. In that case the cabin roof is acting as the "step" with regard to sideways movement, exactly as the deck stepped one is. They are essentially identical above the boat cabin. I suppose you are adding the material strength of the mast itself to that of the stays in a keel stepped mast but that strength is very low (when unsupported by stays) which is why it would be very dangerous to unhook your stays in the keel stepped. It just seems to me that any situations that could break stays will benefit very little from what little strength the unsupported mast might add but it does seem like a way to tear a gaping hole in cabin and another entry point for water. So, the two peices of spagetti are not the same length, the keel stepped one being longer to reach the keel...see what I mean?
While the keel stepped one is longer, it is still stiffer by having the attachment point at the deck. If you want to see this first hand, take two pieces of spaghetti like I did and test it out. Cut one slightly shorter to be the deck step mast and keep one full length to be the keel step. Hold the deck step one at the ends and push to see how much force it takes to bend it. Now have someone hold the keel step version at the deck point and compress it. See how much stiffer it is! ⛵️
Practical reality is that, in lots of places, the choices of boats is not endless and you end up taking what suits you best, balancing all the vatious factors, then sailing her in a manner consistent with her design. I'm from Australia and flew to Europe on a mission to finally enjoy life again, to buy a boat, learn to sail her and to see Europe. So shopping time was not endless for me. I originally thought "keel step or bust", but, on advice I remember fondly every day, I bought and old school, heavyweight Hallberg-Rassy with deck-stepped mast and before long, an episode solo sailing across the Bay of Biscay in 9 metre waves told me I have a wonderful, seaworthy boat - warts and all. So, respectfully, I think you're discussing just one aspect of boat design and doing that in isolation doesn't mean a whole lot.
I assume you are talking about the beautiful Fair Isle and its epic journey through the Bay of Biscay. It is looking at the point in a vacuum. It also doesn’t look at spreader direction, or additional rigging attachment. The goal was to cover just this one topic and not drown out the point with other information. In the end, the boat is designed to sail as a whole, where all the parts compliment each other to create a wonderful machine that makes dreams come true.
I’m not sure I understand. If two otherwise identical boats have (a) a keel-stepped mast of 60 feet which the mast going through the deck at 10 feet or (b) a deck-stepped mast, then it would seem that the bending moment at the masthead is a function of the same loads (wind and rig tension) over the same effective length. Surely it’s the same as putting a finger on a guitar fret board to change the pitch of the note being played.
you certainly don't understand it, otherwise you wouldn't put the post. the question should be: If I have two otherwise identical boats, where boat (a) has a mast attached to the keel (KeelStep) and boat (b) has a mast attached to the deck (DeckStep) ... so the lever caused by the force of the wind acts differently on both boats.
Kobudoka 11 that’s a very interesting point but quite different. If the point where a keel-stepped mask goes through the hull is strong enough, it could indeed act as a fulcrum, such that the forces on the upper portion of the mast could make the mast act as a lever acting against the hull in a way that a deck-stepped mast would not. However we are discussing bending moments which are about the property of the mast itself. Not the same thing, though very interesting.
I'm not sure if I understand your question correctly, so my answer might be off topic. But here it is anyway: First, since your question is technical, and you are asking about bending moments, let me make a technical correction. The bending moment IN THE MAST, is basically zero at the mast head (see Note 1). The bending moment in the mast over the length of the mast will resemble the sketch shown on page 12 (Fig 15-4, first sheet) of this PDF about beams: www.civil.iitb.ac.in/~minamdar/ce317/Lectures/ApproximateMethods.pdf It won't be exactly like this, because the loading is not constant along the height of the mast. But the rounded areas between attachment points, and the sharp points in the curve at the attachment points will be there, just at varying magnitudes. On a keel stepped mast, this diagram represents a single spreader mast. Point A is the mast step at the keel, point B is the deck, point C is the spreader, and point D is the mast top. On a deck stepped mast, this represents a double spreader mast. Point A is the mast step at the deck, point B is the first spreader, point C is the second spreader, and point D of the top of the mast. Note that for both cases, the bending moment is zero at the mast steep and at the top of the mast. The big difference is that the keel stepped mast can have a bending moment at deck level, and this helps to stiffen the lower part of the mast. I must note that at 5:15 Rigging Doctor is not correct when he says "you can never make a deck stepped mast as stiff" as a keel stepped mast. In his diagram, the two-spreader deck stepped setup would almost guarantee greater side-to-side stiffness in the mast. But, this comes with a caveat (actually, there are additional caveats -- but this is just a UA-cam comment, so I'll stick the the biggest one): His diagram is for the side-to-side direction, so I assume this is the direction he was talking about. Typical spreaders and shrouds are very effective in the side-to-side direction. Fore and aft is a different story. In the fore and aft direction, the shrouds and spreaders usually have a limited influence. I could easily see a keel stepped mast improving stiffness in this direction more than a second spreader. Of course, you could add an inner forestay and running backstays for additional fore and aft stiffness. :) Note 1: If the mast has a significant backstay crane sticking back from the top of the mast, then the backstay could impart a torque to the top of the mast, producing a modest moment at the top of the mast.
Question ? Something I’ve been working on? In the event of a knockdown? When the mast and sail fills with water and resist the righting action of the boat? Is it better to have a deck step mast that will break free allowing the boat to right quicker?
That is a loaded question! If the mast breaks, now you have no spar to sail you home or protect you for the rest of the storm! Blue water boats tend to be designed to stay afloat upside down. Air can’t escape so water can’t come in and the boat won’t sink. Eventually, the weight of the keel will pull the sails and rig around until the boat can right itself. If the conditions were that bad, you were probably already reefed so your smaller sails would hold less water and you should come around sooner than later. I would personally prefer to still have the stick up when coming back because capsizing is horrible, adding a demasting will be devastating!
how about mast that bend under such tension but still survive? Something less stiff, more like a spring. Bent when overloaded and then returns to it's proper shape when forces are again within tolerance limits? I'm thinking mostly about mast on tabernacle, and instead of avoiding capsize i look for design that make it less tragic. (There are already bridges in the equation - here comes the tabernacle, but since i'm going to "bow" my mast in front of the obstacle, why not "bow" it in confrontation with too big forces like rollover or failure to reef in time?)
I'm no expert, but I don't think it's a good idea to have a spaghetti mast. Imagine what would happen when the spaghetti mask gets wet. On the other hand, If you were able to carry a lot of tomato sauce...
I would love to know your thoughts on a tabernacle set-up with mine by removing a single bolt I can rig a line to lift or lower the mast on a 34' cutter (sorry, I tried to add a photo without success)
If you are going to be deck stepped, a tabernacle is the way to go. You have so much versatility with that setup! On the Alberg project, we were going to do a tabernacle from a Westsail 32 to keep it deck stepped but instead we will be making it keel stepped since we are planning some big ocean trips. You can email the pictures to riggingdr@gmail.com. I would love to see them as the bowsprit will have a tabernacle so that we can raise it up to save on marina costs.
I've got a tabernacle mast, it's about 43', because my boat was previously berthed at an inside marina in los angeles bay which is under/behind a bridge, but i've never lowered the mast. (I would try it, if there were a better/cheaper crane locally, but there's not, it would cost a couple hundred bucks of crane fees just to get a safety line to try it out.) Because of the tabernacle, the deck-step bracket is extra beefy, which is good, since the main complaint about mast safety on typical deck-stepped boats is that the mast rigging is compromised because of weak deck step hardware. In the ten years of having my boat I have yet to find a rigger who will help test out lowering it to the deck. Personally I figure the tabernacle is the best mast because lowering it allows easy work on the masthead or any other part of the rigging... if there is a rigger who can ever teach how to lower it properly! (duh.) Unfortunately the rigger who put on my synthetic rigging (colligo certified, and used dux) did not know how to re-rig for tabernacle properly, so he removed the various pelican hooks etc from the rigging, and made the rigging 'fixed'. So at some point I will have to rebuild the rigging release hardware so the mast can be lowered rather than fixed (duh!). One of the aspects of having the tabernacle, at least on my boat, is that the mainsheet is ridiculously long, almost 100', because the rigging which 'runs' the lowering is the main sheet, the mast falls forward, and the boom ends up pointing straight up in the air. I also hear from those who previously sailed a lot in the santa cruz area that boats somewhat regularly lose/break parts of their rigging during sails due to weather/swell conditions. Anyways, here's a question about mast strength. How much does installing mast steps weaken a mast? Because, a mast gets a lot of holes drilled into it for those steps.
About the mast tabernacle: in the book “The Riggers Apprentice” they give detailed information on how to lower a deck stepped mast (ideally one with a tabernacle) using the main sheet and the boom as a gin pole. It might be worth a read for you. From what I remember about it, basically the main sheet and topping lift support the mast on its way forward. Using preventers would help keep the boom going straight up as the mast leans forward. Raising the mast is just a matter of winching in the main sheet to bring everything back up. Mast steps: while the act of drilling holes does weaken the spar, the mast step should help return that strength as the structure is strong and rigid on the side of the spar. Strength loss is not the big problem with mast steps, but weight aloft is. Try to get the lightest steps you can because their weight 10 feet up the mast will be 10x the foot pounds of your heeling. The steps at the top of your mast will exert the “height of those steps”x the original weight as foot pounds pulling the boat over when you are sailing. The goal is to keep weight aloft to a minimum and you reduced a lot of weight by switching to synthetic, so it will never be as heavy up there with steps as it was while still steel, but the less you put back the better 😉 I say this because I have seen home made steps made from thick plate stainless steel that weigh a ton and also very light nylon steps that also fold out of the way. Adding steps is a laborious job so it’s ideal to do it once and as best as possible so “improvements” are not needed in the future :)
On a modern cruising boat with a 50 foot mast height like used in the example, a deck stepped mast would likely be about 7 foot shorter then the keel stepped. You would have to break off about 14% of your noodle, then put your wife's hands (err simulated spreaders) back on the noodle and flex it some more. Some deck stepped mast even have crazy over built tabernacle systems that rival or even surpass the normal keel stepped systems in robustness (again with a shorter mast). They basically move the mast step to the roof allowing the mast to free stand, and place the weight on the compression post and bulkhead. The trade off is a slight shift in center of gravity for the boat (something most cruisers don't really adjust their lives for, IE jerry cans, random stuff on deck...etc), and the benefit is a source of leaking eliminated from the boat (water down the center of the mast or though the deck). My buddies tabernacle system allows him to use his anchor windless to raise and lower his mast (50 something feet) without a crane. As far as inside space trade offs, there is STILL a pretty massive compression post that takes up just as much space as a mast would in the salon. Good designers put the compression post in or on the bulkhead, god tier designers put the mast step in a shower :op
Leif Mealone And give up the water collection feature? 😂 how about a big perforated deck plate. For stability of the mast, but allows rainwater to pass through. Below deck, have a split O ring and trough that is plumbed to the fresh water tank?
With respect regardless of where you sail (coastal or offshore) the advantages if a deck-stepped out weigh a keel stepped mast in a modern boat. Deck stepped masts are cheaper and easier to install. Easier to maintain as removal for repairs or winter storage is simpler.( so more likely to be done!). Safety for offshore keel stepped can do a lot more damage if you have a big problem! And that hole in the deck is always a leak issue. Racing or otherwise setting up your rig properly is important keel stepped restricts options of rake and pre-bend . Pretend is important in all rigs to minimize risk of mast inversion . Rake needs to be changeable in life of a boat for example if you change you sails to batten-less for cruising or get rid of those Huge overlapping sails from the 60’s and 70’s designs you may need to change the center of effort and rake is the easiest way to adjust that . Same as if you had bad weather or Lee helm issues. Rake adjustment is your friend.. But as you said maintaining what you have is your first priority ! Good subject Cheers Warren
_"Deck stepped masts are cheaper and easier to install"_ As someone who has stepped 100's of mast, this is incorrect. Which is easier to work with, something that needs 3 points of attachment to hold it up while you are working on it, or one that will free-stand while you attach it? Also there is no price difference between the two. _"And that hole in the deck is always a leak issue."_ And if you do not think that a deck stepped mast has any holes in the deck you fail to understand that there are communication and power wires that need to be run and either one (mast step hole or wire holes) can cause the same leakages issues. _"Racing or otherwise setting up your rig properly is important keel stepped restricts options of rake and pre-bend ."_ Literally the opposite. Deck stepped racing boats have adjustable steps, deck stepped boats do not due to the fact on a keel you have room to move around and have a solid surface. On a deck stepped there is one spot that have been reinforced and as such you will not have an adjustable step like you would find on a race boat that is keel stepped.
@@bobbob6472 Thanks for your comments, from an installation point of view prehaps the keel stepped is easier from new but once that mast has been sealed into the deck numerous times because of the never ending leaks around and down the inside of the mast it will become a real pain. then dealing with the corrosion from the mast heel sitting in the bilge with salt water running down it , yuk! Yeah race boats that have their masts pulled all the time, it matters, not but cruisers will be leaving their masts up forever when keel stepped. From a builders point of view deck stepped is easier and quicker to build. Of course there are small holes around a keel stepped mast subject to leak maintenance but the huge hole from the mast and the internal leaks. Deck stepped every time. Besides why run all those wires thru the deck when a good design could bring them back over the deck in a tunnel , like all the running rigging everyone loves to run aft these days and feed then below in a more protected spot. Re adjust-ability of rake etc , once somebody has sealed that big cruising mast into that huge deck hole with their favorite cured sealant for the last time (they hope) the last this they want to be doing is playing with rake to break that seal! Sure keel stepped masts on race boat have all kinds of adjustment options to effect rake or heel position but they don't care about a little salt water down below on the cushions or fabrics! For the regular cruising boat or so called blue water boat deck stepped every time in a properly designed mast step. i know you will disagree but there you have it from a not racing user point of view. oh check other comments about leaks form deck stepped masts , there are quite a few! cheers warren
I have a question rigging doctor is there a crimping tool available that you can keep on the boat to crimp ends on in case you are where you can't get it done?
The hand operated machines are rather weak and not very dependable, even for lifelines! The proper swage machines are rather large (and expensive). What would be a patch in those situations is being able to tie a small piece of Dyneema to the end of the broken stay, either with three flat seizing knots in a row or a single icicle hitch. The other end of the Dyneema can be tied to the other side of the break so you can keep going. It’s not great but it’s doable. For this reason, they sell “synthetic backup stays” that are marketed as a “spare tire” in the event of a broken stay in a random place. They are light and store easily, and best of all, being rope they can be easily modified to fit the intended need at that time. The short answer: No The real answer: when you find yourself in that situation, you will find something that will make do and you can sail home (but having a keel step mast would help reduce the absolute reliance on the rigging as the mast deck interface would impart some much needed stiffness and support to the broken equation).
🤔 Another advantage of a deck stepped mast is the ability to self-step the mast on water or at the dock. A keel stepped mast requires the logistics and expense of crane services. We had a 19’ West Wight Potter and became adept at stepping & erecting our mast underway to navigate past the low bridges thru Florida’s rivers and canals interconnect the lakes. This of course requires calm weather, no lightning, and a skilled crew. Other applications to this scheme would be the Erie Canal, Inter-coastal Waterway, Canadian & European canals and general passage thru estuaries which have overhanging tree branches. 😎
You are incorrect calling the "deck to mast interface" a support. It is suppose to have clearance from the deck entrance to the mast wall. Secondly a deck stepped mast is shorter than a keel step making it less "noodly". Whether deck or keel, the shroad attachment points, mast to chainplates are the same.
The hole where the mast slips through is supposed to be wedged right with wooden wedges driven in between the mast and deck, making it a secure interface and point of support.
@@RiggingDoctor this of course make the need for keel stepping pointless. keel stepped racing boats have they place for weird race boat reasons and the don't care about water below decks. if you going to make the keel stepped mast ridged in the deck hole then just leave it on the deck, and movement or flex will cause more leaks , problems etc.
Nice video helping us all understand why boats are different. Small issue I seem to think the Merlin Rockets (dinghy show) are keel stepped or the ones I sailed were. Mind you dinghy mast are incredibly flexible.
It does not matter keel or deck as long as the mast is tune properly with a loos gauge . I've seen more keel stepped masts snap then deck stepped . Having loose rigging as you did Herby with your dimenna rigging is an accident waiting to happen ,allowing mast pumping and eventually snapping
My mast never pumps. If I had a deck stepped mast, it would have fallen with my loose rigging. Being keel stepped, I can have the rigging set looser because the mast deck interface grants me more stiffness and that means less wear and tear on the boat. Think about it, which boat is going to break first? The one under incredible rig tension or the one with relaxed rigging? You are aware that a Loos Gauge only tells you the tension in the stay, not how to tune your rigging. When working with older or custom boats, there is not paper that tells you tensions. It’s all by feel! The reason you see more keel stepped masts snap is because the deck stepped mast fall over completely! Deck stepped masts are so reliant on their rigging that any issues lead to a dismasting. On a keel stepped boat, the mast is intuitively stiffer and therefore there is some leeway in what the rigging does. Deck stepped rely on rigging. Keel stepped are helped by rigging.
When it comes to bendy masts it also depends on the mast section and if is tapered. Fractional mast rigs are often tapered with no cap shroud so the top section is very bendy regardless of whether it is deck or keel stepped. Not quite as black and white as portrayed in this video
Tapered masts are more bendy than constant cross section masts, so if a tapered mast is deck stepped or keel stepped, it will still be more bendy that a mast that isn’t tapered, in the same deck stepped or keel stepped situation. To have the stiffest spar, a keel stepped non tapered mast would be the way to go. For the bendiest mast that would be the most adjustable, a tapered deck stepped mast would be your race winner!
The rigging design: I added a backstay adjuster in the split backstay so that I could more easily tweak the headstay tension. I replaced the steel stays with synthetic and deadeyes instead of turnbuckles, but the angles of the stays and number of stays is still the same as it was when I bought it. Being a cutter, it has some “extra” rigging to support the staysail. This includes the inner forestay and two check stays that act as backstays (to a limited degree) and shrouds for the inner forestay. This gives our boat the benefits of an extra point of attachment 3/4 up the mast without the complexity of a second set of spreaders. It also keeps the first spreader at the 1/2 point of the mast instead of bringing them down, so in the event of the mast breaking, we will have 1/2 a mast instead of 1/3 of a mast.
A frames are also better for the air flow over the sail! The break at the first spreader is because the lowers attach to the mast at an broader angle. From there up, the stays need a spreader to get them far enough out so that the stay reaches the mast at the proper angle, and any issues and the efficacy of the shroud vanishes. If you look at pictures of mast breaks, they are always at the first spreader, be it single spreader or 7 spreaders!
Searching for alternate mast tracks, come across this. Great topic & info! also love the nails on your 2nd pair of hands 😜Guess u had Italian for dinner. My guess would be, every spreader creates a weak point, due to drilling holes in the mast. Pros & cons to both, but I prefer keel, plan interior around it.
Questions: Why do you throughout the video show a picture of a compression post for a deck stepped mast every time you mention a keel stepped mast? And why don't you mention that keel stepped masts always leak? I've had both, and I certainly know what I prefer. And it isn't a keel stepped mast..
The compressive load of a deck stepped mast is transferred through the boat most commonly by a compression post. It is much smaller than the actual spar giving more interior space but it is still common which is why I show the compression post. As for keel stepped masts, they don’t have to leak if you seal them up properly. All you need is some mast tape or a mast boot and water will stay out of your hull! The important part is that you have a mast setup that you like and can maintain :)
@@RiggingDoctor Water will always come in through the mast itself. No amount of collars can prevent that, and sooner or later the internal waterproofing of a mast will fail and be impossible to fix. I have yet to talk with someone with keel stepped masts without water ingress through the mast. Admittedly it is not much water that comes in, but you can forget having a dry bilge if you have a keel stepped mast. Anyway, you misunderstood my first question. I am well aware of the physics involved, and if I stretch out my hand I can touch my own compression post. I was wondering why you showed a compression post when you were advocating for the benefits of the keel stepped mast, instead of showing how large they actually are. (at least on boats above a certain size- say from 35' and up) As you say, they are much larger than the post, and in most cases are free standing. The worst case I have seen is one that goes through the middle of the saloon table so you have to look around it to see people on the opposite side. :)
Yes, a small amount of water can come in from the halyards and their ports in and out of the mast. We have a dry bilge but our mast and mast step are located in the shower where the shower sump collects the water and sends it out. I guess mast leaks and shower water all look the same to me in that sump! The pictures I showed were of salons of deck stepped and keel stepped boats. The rather small looking mast that might be confused with a compression post is actually the mast and interior of a few different sailboats that has horribly central masts in the salon. I tried to show the worst mast because it can be better. Ours for example is in the shower, so you never see it and any water that comes in goes into the shower sump. But if I show a hidden mast, it doesn’t drive home the fact that the big spar is going to come into the boat 🤪
@@RiggingDoctor Sorry Sir. Not buying it. That post is circular. Are you going to tell me that a boat that size (must be 4m/12' wide, suggesting a length >40') has a 10cm/4 inch diameter round mast? What boat is that picture from? Also that because you happen to have a boat where the largest common drawbacks of a keel stepped mast have been successfully solved, you forgot to mention them? No, Sir. Not plausible. You are of course entitled to your opinion, and you have stated it in your video. It is the fact that you apparently seem to be unbiased when what you actually say and show tells another story that I am reacting to. Both methods of stepping a mast are perfectly fine, and each have advantages and drawbacks. Your explanation however, is lacking and I wonder why.
You are correct! I made a mistake with the picture. It’s a Catalina Morgan 45 CC and it is a compression post coming down the middle of the salon! When I was searching for horrible salon layouts I didn’t do enough homework to make sure it was a mast and not a compression post 🤦♂️ I tried to present the information as information so that viewers can make an informed opinion on which boat they want to buy. I personally own two sailboats, one is keel stepped and one is deck stepped. One is a boat I feel comfortable on in the Chesapeake Bay, and the other is one I feel comfortable crossing oceans with. The comfort is more based on the size of the boats as one is 30’ and the other is 45’. If properly tuned and maintained, both work just fine. The difference is what happens when things go really badly out at sea. I’m personally more concerned with spreader count over mast step location.
Yeah, I realized that when someone pointed it out. It’s the interior of a Catalina Morgan 45 CC. When I was searching for photos I just saw the giant poorly placed post and thought it was the mast but it clearly isn’t. 😕 I need to make that correction, but it does showcase how annoying a mast would be in the middle of the salon!
I have read the article in a boatbuilder`s magazine that the deck-stepped mast more suitable for the cruisers and the keel-stepped mast for the race boats because the deck-stepped mast usually more heavy (the mast is more thickness) and it is not possible to bend for flatten the main sail when stong wind. The keel-stepped mast is more thin and light and easy to bend.
Well, the right answer is that it depends :) Yes, a lot of raceboats have keelstepped mast, but far from all. It all depends on how the rig is designed. Even deckstepped masts with potentially thicker sections can be easily bent while sailing, if they are set up for it. I'd say that masthead vs fractional forestay make a lot more difference in how and how much you can bend the mast than wether it's keel or deckstepped. Some yachts I've sailed with fractional keelstepped masts had masttops that bent like semicooked spaghetti when you crank the backstay, and some keelstepped masthead boats had basically no way to adjust mastbend during sailing.
You miss one of the main advantages of a deck-stepped mast: portability. If you are going to be setting up and taking down your rig, the deck-step makes life so much more simple. Trailer-sailers are all deck-stepped for obvious reasons. If you're going to be doing canal-transits that require your rig to come down (the Erie Canal, or the Tenn-Tom come to mind), the deck-step is so much easier; the keel-step will require a crane in most cases to get the mast high-enough to get the mast in and out. Like anything else, you need to know what you want your boat to do.
My boat is keel step .. but the deck does not support the mast .. even not under sail. You can run your fingers around the hole. ( we don’t ) The mast moves a bit in the hole but it hardly uses the deck structure for stiffness
Sounds like your mast wedges have rotted out and fallen away. All you need to do is cut some white oak into wedges to wedge your mast again. Check out this post that goes over how to wedge your mast properly: www.riggingdoctor.com/life-aboard/2016/2/29/wedging-the-mast-deck-partner
Wow.. this was great. I am looking at sailboats. This was very helpful. What do you think about using a drone to check your standing rigging versus going up the mast?
What about racing boats say they are made with sitka spuce masts that are keel stepped sa my boat loa is 41' with a 60 foot mast and and a 22 foot boom and you would say this is a cruiser or racer yes I know this is not a newer built built boat but at the same time this boat carts 740 sq ft on main and 240 on jib sail .with a spinnaker she runs a total sq footage of 1550 sq ft she was built as a racer that could cruise with a bendy stick and usually would move on about 9.5 knots of average speed comfortable as can be probably not but for a boat from 1936 what would you expect
Very true. We will sit still in a light breeze weighing 18 tons while a much lighter boat will be approaching hull speed. They get places fast all the time where we only start moving in a small craft advisory.
Something you didn't address is that a keel stepped mast can be a lot lighter, thus giving you the same sort of "bendiness" as a deck stepped mast, which is important to racers. I have a 30ft IOR boat with keel stepped mast, and two people can pick up the 50ft mast. My friend's deck stepped mast for a boat of similar size takes at least 4 to pick up. My boat is also fractional rigged which gives me terrific control over the main sail shape, another important thing for racers.
Sorry. Lots of misinformation here. In my experience, the majority of racing sailboats have keel stepped masts. High tech race boats may have a hydraulic jack underneath to adjust the rig tension. The compressive forces on the rig are substantial. Whether or not your mast is deck stepped or keel stepped, is not really a factor in bending the mast to the desired shape. Either system properly designed can do the same thing. Your pasta analogy fails. You should not be comparing 2 lengths of pasta that are the same. You have one that is the added length of the below deck portion. If you held the pasta at that intermediate point, both now the same length, they have equal stiffness. More bendy mast sections do need more sets of spreaders to keep in column under load, but being deck or keel stepped doesn’t change that.
A deck stepped mast is more bendy than a keel stepped, and on yachts that convert from keel stepped to deck stepped, the entire spar needs to be replaced with one that has thicker walls because simply cutting the bottom off and stepping it on the deck will yield a mast that is way too bendy. Having that added point of contact between the deck and mast adds a significant amount of stiffness which lets the mast be made of a thinner walled material for the same mast height (bridge clearance).
The premier ocean racing class TP 52 has a keel stepped mast and plenty of ability to control sail shape with bending. From J boats, C&Cs, Swans, Baltics, Tartan have keel stepped masts and are actively raced. It all depends on how you design it. it might be interesting to invite a designer into this conversation.
Actively racing a blue water boat isn’t the same as a purpose built race yacht. Pogo and Beneteau First are deck stepped with racing in mind. At the same time, VOR Open 70 was keel stepped, allowing the mast to be very light because of the added rigidity that comes from the mast/deck interface. To get the mast bendy enough, they could make it thinner and lighter which is wonderful on a spar that is over 100 feet! It all comes down to what the designer wants and the purpose of the yacht. In the end, deck stepped masts are bendier (so they need to be thicker to not be bendy) while keel stepped masts are stiffer (so they need to be thinner to be bendy).
@@RiggingDoctor Beneteau first deck stepped ?? Not anyone I've sail and stepped the mast all keel stepped 36.7, 35.7, 375, 38, 45.5 all keel stepped even mumm farr racing boats are keel stepped and I have seen them demast
From an Engineering point of view the deck stepped is a stayed, simply supported beam, the keel stepped is a stayed, cantilevered beam. The stress patterns in both are very different at the level of the deck. There is no right or wrong, just that they are designed differently (or should be!)
And all of this is not absolute as you said. We race in low PHRF on the most visited USACOE lake. Last year we were top boat for the year on a Flying Tiger 10 meter. It's keel stepped. But it is also fast. Mast, boom and rudder are carbon fiber, double spreader on a 33' boat. But we win on the I dimension.
That is a very impressive setup! Maddie gets mad when I start drooling over racing boat rigs. I think she’s worried I will convert our cruising boat and that would mean more work when underway 🤣
@@RiggingDoctor The FT 10 is an awesome racing boat. We are considering an offshore race this year. But I would never want to cruise on a racing boat. There are more lines and controls than I would want to deal with while cruising. Vang, Cunningham, Coarse and Fine Mainsheet tuning, constant backstay adjustments, weight on the rail, off the rail, on the leeward, back to the high side rail. There is never a relaxed moment when sailing this boat. Absolutely no opportunity to read anything except the race course - NO! Starboard on this rounding! I was only commenting on the fact that it's keel stepped as a race boat. I'm looking forward to an Amel Super Maramu, Oyster 485, or Swan 50+. There is nothing like offshore with steady wind.
Great Video! I love when you tackle the physics of sailing, but I'm confused. If the length between the deck and the mast head is the same in each case, then shouldn't that spar have the same flex points no matter if it is fixed in a deck step or securely fitted through the deck? If the keel-stepped mast is securely fixed at the deck, then the below-deck portion will not aid nor hinder flexing. It is out of the equation entirely. Isn't this like a capo on the neck of a guitar? The vibrations (bending) in the strings stops at the capo. Wouldn't the deck fitting work the same as a capo on the neck of a guitar, and stop all bending below the level of the deck? If so, then a deck-stepped mast, and a secured deck-fitting on a keel-stepped mast, should work the same for the same length above decks. In your example with the spaghetti you are bending the spaghetti with BOTH hands around the single or double secured spots (supplied by your wife's hands), but in reality the end of the mast down in the keel is not under sideways force. All the side forces exist from the deck upwards to the mast-head, so all the matters is the length of the mast ABOVE the deck. There ARE downward compression forces which might be better to be loaded onto the keel vs the deck, but there are no sideways forces below deck. What am I missing here? Great Video! Thanks for all your effort.
Similar thought. The keel step mast is longer than the deck step mast. It is longer by the length from the keel to the deck and 'would' experience more torque if not for the deck. Provided the attachment point on the deck is solid, the applied torque providing lateral shear force pivots at the point of the deck and headmaster. In other words, The forces above the deck are equal between the 2 setups and everything below the deck is part of a different equation - eg: if u have no shrouds at all. Does this sound right?
@@DarenSpinelle the deck is effectively another spreader on a mast that is "keel step to deck" metres taller, and in most cases you can treat the deck as being infinitely strong (not really, but for purposes of accuracy when the mast is represented by pasta :) ) you can get _some_ bend between deck and keel, consider the deck step acting like a pivot point, or the fulcrum in a playground see-saw. As practical example, place a ruler flat on the table, with a few most of it hanging off the edge, and a few inches on the table - hold in place with a finger tip on the end, and at the table edge - now bend the free end of the ruler down, you'll see the ruler lift a little off the table.
quick _dry I agree with that. I think my question came down to; does a keel step allow you to use a thinner/weaker/lighter mast and achieve the same 'strength' (keeping everything else equal- width of spreaders, height of mast head, streamers etc.)
@@DarenSpinelle yes... but with some hand waving :) . The mast section has to be strong enough to resist the bending in each panel (from spreader to spreader) thus more spreaders = less bending, but it also has to resist buckling under the compression induced by all the rigging. My understanding is that this is part of why an oval section works for a mast - it has all the spreaders to make small sections in the transverse direction - but fore and aft, you don't have much because it'd interfere with the sails - it's one unsupported section from deck to headstay. If you see the equation for a buckling column, the coefficient for a column pinned at both ends vs a column pinned at one end and fixed at the other, the fixed end column has more advantageous coefficient - i.e. lighter mast, though diminishing returns as the mast length grows. There are some good discussions on deck v keel step over on boatdesign dot net with input from longtime professional boat designers. Alternately, it should also allow for less loading on the rigging (or a higher safety factor depending how you look at it), or lighter rigging - same with using a wider shroud base
The comments below were very good in exploring the point. While the bottom doesn’t twist, it is part of the compressive force on the spar which will cause the mast to bend. The force is all pulling down, but the mast doesn’t know that it’s being pulled down onto a solid mast step. It just sees itself in the middle being compressed from the top and bottom. When it bends from a compressive force, it bends regardless of which side is being pushed. Having more points of attachment makes the spar “stiffer”. This means that a deck step mast will always have one point of attachment less than a keel step because it doesn’t have the mast/deck junction and therefore will be bendier. As a result, a deck step mast (with the same bridge clearance as a keel step version) will have a shorter mast but need a thicker walled mast to give it the needed strength.
Sorry mate you’re wrong, a deck step mast is fixed at the deck and therefore the same strength as a keel stepped mast. Fractional rigged masts on the other hand are a completely different story.
I think you should give the spaghetti demonstration a try. Keel or deck, fractional rig just allows more force from the backstay to tighten the headstay. They tend to be deck stepped because they are bendier and therefore easier to bend and get that tension on the headstay. Keel stepped are just stiffer by nature. Give it a try, it will blow your mind!
Sorry but you are incorrect in your assumptions. You show Volvo boats as examples of deck stepped as being better... They aren't keel stepped because of the location of the canting keel box. Imocas have rotating masts so again deck stepped. Secondly all these offshore race boats that are deck stepped have carbon bulkheads with zero space inside as the boat translates it's stiffness directly to the mast connection. Even that's not the end of it as tp52 is canting and keel stepped mostly inshore boat. Wild oats xi is keel stepped canting offshore. Comanche it's competitor is deck stepped because they wanted to make it with uninterrupted carbon stringers...Third all these boats have running backstays at the hounds as bending your mast and driving lower sections forward is slow. You want to bend the top section only in sail trim...Better to ask Bruce Farr than Mr spaghetti. Regards
I think you missed the point. He was explaining basics not getting all up into racing. Now if you want the guy to spend 4 or 5 hours to teach ever aspect, send him more then a piece of pasta to show the demo with and then he might consider your input on the level of teaching. I get all the point he made,, Anyone else?
Racing boat do lots of weird things for lots of weird reasons as you point out. they are not good examples for a subject about and for cruising boats and cruising people.
Too much going on ( BS ) for a newbie. Sea U in a year or so when I have a little more under my sails. All information is good information for someone who is learning. Thanks
These days, aluminum masts seem to be the usual. A wooden mast behaves much differently under load. 'Once upon a time' back in the 70's, I built a Herreshoff three mast schooner, I built the spars of spruce....11+ growth rings per inch. Unlike Aluminum, a wooden spar can go a bit out of column and live, aluminium MUST be kept straight. Personally....I would be very loath to sail offshore with a deck stepped mast of any sort. We once spent a week in the westeries blowing 35-40, boat speed around 8.5 surging to 9 now and then, 15 foot or so swell....so calm in the troughs. I'm 75 now and still miss living on the water. -Veteran '66-68
Hi Doctor...Good explanation...However you totally left out “loaded vs unloaded” rigs...deck step = always loaded. Keel step can be unloaded with grid and vastly better for performance and boat wear....Thanks and I look forward
Very true, I keep my Rigging on the looser side of life to reduce the amount of wear and tear on the boat. With a deck stepped mast, my rig tension would lead to catastrophe!
that sounds scary! there is nothing about a keel stepped mast that allows you to have a looser rig . You will just put unintended stress on the mast at the deck opening , potentially leading to failure and a mast over the side with a large hole in your deck! correct tension is your friend.
WARREN MYNAME there is a difference between correct tension and high strung. If I had aft swept spreaders, high aspect ratio sails, and inboard chainplates, my rigging would need to be very tight to be safe (deck or keel stepped). Having a lower aspect ratio, lateral spreaders and chainplates on the edge of the deck, the loads are lower and so is the rigging tension. I’m not saying that the shrouds get tight when the mast leans over, but when the mast is straight they have a little play in them, and instantly load up when they have wind on them. The leeward shrouds also go loose in winds of 25 knots as they should. Low stress and low loads make the boat happy but tight enough to be safe.
Rigging Doctor Agreed , with a wide rigging base the tension can be less. As you know you only have to look up the mast to see what’s going on when you are cranked over with the rail in the water to know if you have it about right. That’s also why catamarans can have such relatively loose rig tension the wide base. Cheers Warren. Ps defiantly a contentious subject!
warp21drive whenever we are under full sail and heeling about 20*, I go forward and take a peek at the mast to make sure it’s in column. I know I keep the rigging on the slacker side of things because less load means less stress on everything! I also know that toeing the line means that I need to check if the mast is doing alright. So far, for the past 3 years, the mast has always been in column when I look up on either tack. Low strung life for me! ⛵️
My sailboat is located on a lake (Oneida Lake, NY). I have owed both styles of sailboat. If I want to travel to the great lakes or to the Hudson river I have to take my mast down. Much easier on my deck stepped sailboat. I never have a wet bilge. Having an extra 6 or 7 feet hanging over the boat is not fun when traveling with it down. If the rigging is inspected properly and replaced every 15 or so years I see no reason to shy away from a deck stepped mast. I have found that things fail when they are past their useful life or not maintained. If you are in 40 knot winds on a 35 year old sailboat that was kept in saltwater its entire life with original rigging it doesn't matter if it is deck stepped or keel-stepped its only a matter of time. On a different note. I see lots of conversations between what is considered blue water and not. Blue water to me means very well maintained (Replace things on a schedule and not wait for them to break, inspections, maintenance). I would pick a very well maintained Catalina to travel across the Atlantic over a not so well maintained Hans Christian or Hallberg Rassy. I've been on a few blue water boats that I would not take out of the marina. I think new sailors get hung up on terms and less on the condition and maintenance. I did when first looking into sailing.
agree 100%. and those keel stepped masts that never get removed and corrode away in the bilge , just waiting for the first big blow and the mast base to crush a little , rig goes loose, swaying mast and momentum causes an overstessed mast and it lets go leaving you mast less in a storm with a huge hole in your deck! there are various examples on YT of people buying an old boat and finding the keel stepped mast below the floor in the salt filled bilge half rotted/corroded thru! put my mast where i can see it every time! every day!
Pointing is more affected by the sheeting angle of the sails. If the headsail is sheeted to the rail, it can never be trimmed in as tightly and will not point as high. If the sheeting point is in on the deck, then the sail can be sheeted in very tightly and point significantly higher. The limiting factor to this is where the shrouds attach, as the Genoa needs to sheet outboard of the shrouds. Boats with shrouds attaching at the side of the hull won’t have as tight a sheeting angle as boats with the shrouds very inboard on the deck, and thus a much tighter sheeting angle.
I’m not sure what you mean by an egg beater below deck, but you will have a hole in the deck where you can stick the boom to jury rig a tiny mast (as long as you still have a boom)
Danged fat fingers. Unless on specialized racing craft, deck stepped masts must either have heavily reinforced decks or a compression post to carry the weight and thrust loads of the mast. The handiest means of attaching the mast to the deck is via the venerable tabernacle, which allows the easiest method of initial rigging, periodic maintenance, and emergency non-assisted repair to the mast. It helps when you meet that low bridge along the way, too. Laying the tabernacled mast aft into jury-rigged or permanent crutch, using the forestay and spreader or whisker pole to keep a good angle, is such a simple matter. As to reconfiguring those pointy-headed sails onto a shortened mast, I recommend you research gaff, lug, and sprit rigs as options for emergency rerigging. Compared to your original elegant pointy sail rig, they are not as efficient, but they are certainly more efficient than the emergency low aspect ratio sail rigs your photos show. Old timey thinking here.
I feel like your example is incorrect. The two masts (pieces of pasta) will not be the same total length. Mast length is about height above a boat. If deck-stepped mast was 30 feet tall (and thus 30 feet above the deck) and the architect decided to make it keel-stepped then the mast is not now 20 feet above the deck. In other words, you should be comparing a 10 inch piece of spaghetti with being pinched at 3" with a 7" piece of spaghetti. Right?
Mast length is different from mast height. Mast height is the height above the deck that the mast sits. Mast length is the cut length of metal for the spar. If the mast height is 30 feet, then on a deck stepped boat, the mast length would also be 30 feet. On a keel stepped boat, it might be more like 40 feet, since it has to go through the deck and interior to rest in the keel. So you would be trying two pieces of spaghetti, one longer than the other, but both held at the same points (with the addition of the end being held on the longer one. Say on a 10 inch piece, held at 0” 5” and 10” (deck stepped) On a 13 inch piece, held at 0” 5” 10” and 13” (keel stepped). Give it a try, the difference is remarkable!
The section inside the boat on a keel stepped mast gives the section from the deck to the masthead more rigidity due to the support from the mast passing through the deck.
I think you may be a bit confused wrt mast bending. The deck step is a point of rotation that makes it harder to put a bend into a mast (think: load up the back stay and the mast tilts back). To bend a deck stepped mast mast you use baby forestays, fractional rig or forward mounted lower shrouds. In a keel stepped mast these serve to control pumping.
They actually set the mast bend in both setups. The mast pumps when the rigging is too loose for the wind conditions. Deck stepped masts need much tighter rigging so this usually never occurs. Keel stepped masts can have looser rigging because the mast deck interface gives it a lot of stiffness so the rigging doesn’t need to stress the boat by being so tight.
Thank you for your video. An area you brushed over and in my opinion incorrectly. I am referring to your comment that to cruisers are not racers and "cruisers do not care about adjusting everything". Although, cruiser should most certainly care and always look to race techniques to get the highest proficiency from whatever rig or hull type you operate. I have rarely seen seen two sailing vessels get together and not want to tweak every ounce of performance from there vessel. In my opinion cruisers should look to there racing compatriots for proven examples for sail trim and performance. Jibsheet lead, backstay tension, traveler, luff tension, Sail draft, camber, mainsheet, halyard tension and so forth. Being able to adjust and understand the performance capabilities of your vessel is paramount to good seamanship.
Hundred percent agree with this. I work in the traditional vessel world of sail training ships, gaffers and square riggers and just because the vessels are 200 years old in design doesn't mean we don't take pride in squeezing every ounce of performance out of them when the right circumstances present. Working aboard the three master L'Hermione if the captain came on deck and the yards were braced a point or point and a half off of where they should have been to get maximum drive for the given wind angle he would look at the watch leader and make a remark, and the crew would be scrambling around to adjust nearly 40000 square feet of sail to the inch to make sure that every sail was working at it's utmost efficiency. Those vessels were complicated machines and some of them performed extremely well for their day, but not if they were sailed sloppy. The good captains and mates of those days were always trimming and watching their rig closely no matter the conditions.
I think having the instinct to be constantly alert and looking at your rig and adjusting (which some might think is a "racer attitude"), and to know exactly how the boat will perform on every point of sail in every condition is just the basis of seamanship. My partner and I have a Heavy displacement cruising boat now and I've carried my experience forward. You don't need to be in "race mode" every second but the vigilance and intimate knowledge of your vessels trim that comes from the racing side of things will benefit cruisers if they need to get themselves out of sticky situations, eg. Beating off a lee shore following an engine failure, how to drive the boat safely downwind in a blow, or how to heave-to well, knowing exactly how much sail to set and trim it.
Rigging doctor puts out lots of good stuff, but @Bo Jangles is right on this one.
I agree. Put two sailing boats in the same body of water, on the same course and there is automatically a race happening even if they are totally miss-matched. I used to have a Ruffian 23 1/4 tonner which I had great fun with, passing much larger boats
I think the point should be emphasized that if you are deck stepped, you can still cross oceans with a single spreader. Many, many designs do including some of the most popular offshore boats ever created like the Westsail 32 and the entire Hans Christian line up. Also should be noted that if a keel step mast fails entirely it can completely can open the coachroof when it levers over. We have seen it firsthand. Good video otherwise, just be careful when making statements not sound like hard fast rules for the people that know no better.
I agree. Lots of famous offshore boat designs are deck stepped. Hallberg Rassy comes to mind - even their boats from the 70s are deck stepped.
Can opener, is this the general issue in FG/aluminum mast vessel's?
Wooden vessel and box spruce masts.
@@corviswood its an issue with any boat with a keel stepped mast if the rig fails and does not break at the lowest spreader generally cause by a failing chainplate
@@SailingVesselPrism Interesting. Keep on loving my Spruce box main, keel stepped single spreader not going down or getting in if it splintered. 😉
Any racing boat I have been on had a keel stepped mast and my 1/2 tonner is keel stepped too. The reason is, when the back stay is hauled on, the load is transferred to the keel and not to the coach roof which can give way or deform. Cruisers like deck stepped masts as, the constant leeks through the deck are not a problem. I thing the narrator needs to re-think some of his points
There are exceptions to all generalities and you just listed the two exceptions to the two generalizations.
Almost all deck stepped masts have compression posts (with some exceptions, Albin Express comes to mind first). But yes, racing boats actually do have keel stepped masts for a reason. Simplest answer is you can get same stiffness with thinner mast, which is good for weight saving and less windage. Long answer is trimmability. With Keel stepped mast, you can adjust prebend and forestay tension by moving mast step fore-aft (and/or adjusting fore-aft positions in the mast partners). But say the partners is not adjusted, then moving keel stepped mast aft on the mast step, you create more prebend and less forestay tension. Second thing to consider is sidebend caracteristics. For heavy wind you want mast top to bend leeward, creating windward sidebend in mid section. This helps to open the slot between jib and main. And considering the deck stepped mast adds stiffness for the lower part of the mast, this will be helpful in creating windward sidebend.
Every racing boat I've sailed has had a keel-stepped mast and the cruisers have had deck-stepped with compression posts. I think stopping coach-roof leaks is one of the motivators for the latter.
Leaks like that are easy to prevent. It does however require some periodic maintenance and inspection. But not to the point where that is an issue. I had a new boat with that leak. I only knew because the bilge kept getting wet. I complained. He said, as if I were a dolt, It’s a boat.
I finally tasted it. Fresh water. I went topside, adjusted and lubricated the seal. Then climbed the mast and sealed found inspection plates left off the mast so that rain would get into the mast. Made the mast as tight as I thought necessary and appropriate. Bone dry bilge and sump.
Diverting water is not rocket science.
I don’t consider that in my decision about mast stepping.
Or internal space.
This is just like listen to one football supporter trying to explain a supporter of the other team, why they’re team is the best.
You are so totally in love with your own choices. That does not only include the keel stepped mast.
They each have their place and it totally depends on your goals with the boat.
Big advantage of a keel-stepped mast is that when there is no load it is self-supporting even with the shrouds off - comes in mighty handy when stepping/unstepping the mast (takes a lot of stress off the process).
Couldn't agree more. 2 guys and a gin pole, you are good to go. Best place to check your rigging too.
Yes but you can`t unstep the mast yourself (without a crane), you can with a deck-stepped mast.
Except for the step where you need a crane?
@@kjaubrey4816 To put the boat into water ?
@kjaubrey4816 funny finding you here. You going sailing? Ain't seen you in forever man. Hope all is well.
The primary question between deck stepped and keel stepped masts is structural. The forces on a mast are compressive in nature and not bendyness. Well maintained rigging keeps the mast in compression, which can equal the weight of the boat or more in a stiff breeze. So the actual question is; do you want the compression force on the deck or the more solid keel? In my experience, no amount of deck reinforcement including bulkheads or compression posts, can keep the boat from deformation with a deck stepped mast. In addition, keel stepped masts stay in tune longer simply because of this deformation of the hull and deck structure. Any offshore passage-maker will have a keel stepped mast, deck stepped masts are for daysailers.
You are forgetting that the sail also imposes loading on the mast at 90° to its main axis.
@@jonathanwetherell3609 No, because all the loading is converted to downward pressure by the rigging. The mast extrusion, if designed properly, takes any side loading between the rigging attachment points, but the primary loading is downward force at the mast step, sometimes up to twice the weight of the boat.
@@oceannavagator The UDL of the main sail imparts a bending moment to the mast, which is a beam. The beam is supported by the rigging, which imparts both a compressive and support loading at 90° to the mast/beam axis. The deck mounted mast has axial and a load at 90° at this point. The keel mounted mast has both bending moment and a load at 90° at this plane.
@@jonathanwetherell3609 Look, I get that the stick has a bending moment but that force is resisted by the rigging if in proper condition transfers the force to the mast step downward and the side stays upward. Because the mast is in column, any bending moment now heels the boat over. Any dismasting that I have ever seen that wasn't a rigging failure (meaning that all the rigging was in place) was a result of the mast coming out of column, ie going S shaped between attachment points which slacks the windward stays and allows the stick to fail. The extrusion has to be strong enough to resist the pressure that the stays impart on it, When deck stepped, the cabin top will flex downward, slacking the stays, allowing the mast to come out of column. Some boats are so bad that when going to weather you can't even open the forward cabin door due to the distortion in the main bulkhead.
There is one extra consideration in my opinion.
A deck stepped mast can be lowered without use of a crane. Yes I know it's a pain in the backside but sometimes you really want to be on the other side of that bridge.
Very true, the boom can be used as a gin pole and the entire can be lowered in a safe and controlled fashion.
Pesky bridges 😂
I used to own a Soveral 36 racer/cruiser, hull #9. Back on the day it was the only boat Ted Turners team couldn't catch...its very fast and its keel stepped!
On our new boat which is a three masted Schooner we have deck stepped all the masts, whereas the original design had all three keel stepped. We find that with the deck stepped masts we don't have any of the original designs issues with water ingress when shipping green in heavy weather.
I'll never look at multi-spreader masts the same way thinking about sailing home under a patchwork rig.. interesting stuff!
🤔
Deck-steep mast: Another aspect of a deck-step mast is the ability to step & unstep the mast without crane 🏗 support for canal and inland travel in areas of low bridges. Every time the mast is lowered, the rigging presents an opportunity for close inspection without going aloft. If a breakage occurs one is not left with a potentially jagged mast in the cabin and water pouring in.
A “D-S-M” for a larger boat, lacking a compression post, needs to be designed with lateral arches to transfer the load to the frames, and then on down to the keel. I’ve wondered if a “clam shell” clamp on the cabin top with a pivoting shoe might aid in mast tuning.
When we rebuild our Alberg 30 (our next project) I’m going to be putting a tabernacle on the deck stepped mast to allow for just this very thing. The ability to raise and lower the mast will be invaluable while cruising into areas that we were simply kept out of by a low bridge.
@@RiggingDoctor We devised a mast lowering arrangement for a West Wight Potter 19 which was quite safe, allowing us to raise & lower the mast while actually underway (as long as the surface weren’t too rough ….. otherwise it was a dockside evolution). This allowed us to slip under low bridges and have the mast back up and tuned before reaching the next lake (Florida & Gulf sailors).
Ever since then I’ve been considering how I could achieve the same arrangement on a larger boat where the weights are higher. This, while saving time & support fees is mostly an issue of self reliance and autonomy for us.
I really appreciate the videos you uploaded on Dyneema. It seems like a no-brainer to me. I worked in the Nuclear Industry for forty years. We used to lift 110 Ton Spent Nuclear Fuel Casks with very heavy, and dirty 🤣 wire and shackles (about an 80# rig per side). Well Kevlar slings came into favor (light as a feather, very pliable and much stronger) ……… the wire ropes were quickly retired.
I think that other advantages of Dyneema is that by having less weight aloft, in addition to stability, it will present less of a risk of injury from the standing rigging upon failure compared to wire or worse rod rigging. It is also light and pliable enough to even have spares onboard for longer blue water adventures to remote places.
Herbie, Thanks so much for your insights on rigging & cruising pointers.
great info.. Even cruising sailors, well me, like to be able to bend the mast. To depower the main primarily. Crank on that backstay and push the mid mast forward and you dont need to reef nearly as early.
Trimming the sails by moving the spar is incredibly useful!
Won't work with a mashead rig. Bending only works with a fractional rig.
If you want a lot of mast bend, normally you design that into the mast and rig by doing things like going to a fractional rig with the mast tapered above the forestay attachment. You can do that with a keel or deck stepped mast. However. deck stepped masts generally have a stiffer spar design (larger and heavier) than keel stepped designs. You can still bend a deck stepped spar particularly if you go with a fractional rig and tapered mast, but it always takes more force that with the lighter keel stepped spar. A big advantage of a deck stepped spar if you sail in a place where you haul out annually is that it takes less time and is thus cheaper to step and unstep deck stepped spars that keel stepped spars.
SW, you completely forgot to mention the very large compressive forces that rigging imposes upon the mast that are transferred to the mast step, either at the deck or at the keel. The person who designs the hull has to put a whole lot of strength and weight of materials to support that compressive load, which may be on the order of many tons [or tonnes if you are a metric person]. The decision about where you put those compressive forces has a lot to say about how the boat itself is built.
This one hit home. Had new rigging this year marina had boo boo my spar is in two pieces. They made good new mast running and standing rigging.
Ouch! At least they did the right thing and got you squared away.
I have a respect for you creating videos free of offensive language. Children are watching everyone.
We wanted our videos to be kid friendly!
Dude, children already know every bad word and then some you even don't know. Wake up.
Why are children watching 👀?
@@Shepherdservices317 so they can sail away!?
Even though I am 40 years old, I can never tolerate offensive language.
So it seems that it is the spreader attachment that introduces extra stresses & weakness in the mast - is that correct ? ?
& if so how to design a rig that does not need spreaders & can perform at least as well?
Great video. One thing: Many, I believe most, racing boats of all sizes have a keel stepped mast. It is preferable to lead the loads into the keel.The touchpoint at the deck has many advantages. You can even use it to control mast bend precisely. In a 420 for example, you control with some simple removable pieces of wood how much bend you want to apply in different wind conditions. Most biggers boat also have keel stepped. As you said, rigging can be lighter. As an exception many French offshore boats have deck stepped. I believe even as a rule. They take dismastings for granted and see the hole in the boat as the bigger problem. If your mast goes overboard cleanly, you still have the deck step as a jury rig attachment point.
For a proper offshore boat whether it is a cruiser or a racer, I will choose deck-stepped every time for safety and convenience reasons. If something bad happens to your rig, with a deck stepped mast, you stand a good chance of keeping the boat watertight which should be your top priority, whereas if you have a keel stepped mast, the chances are that there will be a big hole to plug or even worse that the mast comes off damaging the roof! Also IMHO having to care for extra diagonals is a mere inconvenience compared to the constant battle of keeping the mast / roof junction watertight on a keel-stepped boat. French offshore racing classes (IMOCA and mini 6.50) have prohibited keel-stepped masts for safety reasons.
Finally it isn't uncommon for racing boats to have keel-stepped mast because it lets them use a lighter mast section with a smaller inertia thus they can tweak its bending more by tuning the tension in the runners, the backstay and the checkstays. With great powers come great responsibilities as if you invert the mast with the checkstays, chances are that it will come down.
Very well said.
The hole in the deck is always a bother to us. I need to freshen the seal yearly, but thankfully the mast is in my shower so any leaks are not the end of the world!
Hear Hear very well said. keel stepped might be a convince for the lazy rigger but that's about it.
WARREN MYNAME if the rigger is lazy, he would hate frequently being called to work on the guys boat about the leaking deck seal 🤣
Alot of good information there , thank you for making his video ! Find me to pass it on to a couple buddies of mine .
Great video, thanks for sharing. One topic not covered is that of water ingress. I have yet to come across a keel stepped mast that does not leak a little water. Not a catastrophe but can cause ongoing problems with mould and moisture. Another aspect is whether it is better to have a mast completely fall over board and can be cut free (deck stepped) or a snapped mast still attached to the boat and hard to cut free (but not punching holes in the hull). I like the way you say that these are all really, really bad situations. the question is, which is worse.
Why would you cut free the deck stepped mast that fall overboard ? Depends of course on the size of the boat and conditions, but it is doable to just lift it on board ( I lost a mast that way on 28 ft boat, needed help from guys from the club with a dingy, to de-rig the mast in the water of sails, but then we just piled everything on board and motored home )
I thought there was a lot of good information here even though in the beginning I think when you first described the primary diff between the two and then went into the spaghetti lengths and bendability you should have mentioned immediately that the deck “interface” acts as a segment creator so that comparing the two WITH NO SPREADERS the deck stepped mass has one segment while the keel stepped mast has two segments. Then go into spreaders. You don’t mention that a keel stepped mast deck interface is a length shortener. Not too big a deal. I’m irritated when writers go off like that because I am an OCD reader. I hang on every word the writer says so long as I’m learning. And it was immediately clear to me that you met the bill. So I hung in there. There is so very much to say about this subject but it all comes down for me (who as a sailor did not spend any time in marinas drinking with my business friends. I’ve been in some very unfriendly weather and I have met half the famous ship wrecked sailor-authors. The serious sailing community is very egalitarian.). I taught. Computer science. When a subject is nuanced enough it is useful to teach in a series of understandable white lies. Then when the students have more understanding tools, set the record straight.
For me: I would never own a boat that was not keel stepped.
There are no interior decorating negatives. It’s not even a Bauhaus function over form aesthetic. You want smaller spaces below. It’s not a condo in Boca Raton. It’s a boat. You want multiple function purposes spaces. You need hand holds. It’s a sailboat. You will need to cook and sleep and shit in 60kt winds with crashing packed 40 foot walls of water. IF you’re a sailor and not a rich guy with a boat.
When I was 13 I read John Masefield’s Sea Fever.
I was transfixed. It was for be what Alice in Wonderland or Harry Potter were to gazillions of normal people! I kept reading it. I memorized it. I knew that someday I would sail. Despite growing up away from sailing and the water and having a father who was not a sailor and had no interest in it. He did take us out on a motorboat two times. I was irritated by the idea of the noise and the fumes polluting the Chesapeake Bay in off season. And I saw sailboats heeled over catching the wind and silently accelerating till they got a bow wake and then seemed to stop accelerating and I was being drowned in data points, trying to reverse engineer all the effects I was noticing into the principles and the control surfaces.
When I first sailed it was after I purchased my first sailboat. 46 Beneteau. Everyone said I was nuts. I was 50. Just retired. Asked my wife if she would mind if I bought a sailboat and sailed away and Dre could come and visit me from time to time and sometimes depending where I was and when, I could fly back for a while. She said, You betcha!
At the time I was not sure if this response was a good thing or a bad thing but I wasn’t going to look a gift horse in the mouth. At worst I’d have to pay on Tuesday for my hamburger today.
As Norman Maclean said, I am haunted by waters.
And beams. And moment arms. All good technology at first seems like magic. It’s indistinguishable.
The only tweeking ii do when cruising (50,000 miles) is the rum glass .My last trip up to Tonga in 55 ft Warwick MS we averaged 9 kts , not to bad for a 30 ton yacht .
That’s the Cruising life! Sit back and let the boat get you there😎
A major problem.is we have racing rigging on cruising boats. The spreaders and stays on mty beneteay lu 44 has the mast chainplates on the edge of the deck and heavy mast section . Big wide spreaders. I see similar size cruising yachts with lighter sections and chain plates well away from the edge of the deck. Not as much leverage and requiring tighter shrouds to give same supports. Ive also not seen a mast break at the deck mainly at the upper stay. I also have twin backstays. Only thing i will add will be an inner forestay fir a smaller headsail.and to add support to lower mast section.
Yep, people want the racing style but forget that the lifespan of a race boat is the race, the lifespan of a private yacht is supposed to be a lifetime.
@@RiggingDoctor you hot that right. Most modern cruising. Boats are lacking in requirements for cruising. Fair weather sailors. I think the only yacht in the club with wider spreaders is the nautor swan 54 in the pen opposite me. Also got solid stainless rigging but not in mast main which is good. Down below is magnificent but i would feel guilty cruising in her. Beside i would need buckets of dollars to keep her in good condition and use her a lot. My first yacht i bought hull and decks and fitted out 40 years ago and is still sailing. I used lots of quality teak. Now im happy with less timber.. best regards and happy sailing
Good to see you guys again 💃🏻😎
Very informative...
Is it fair to summarize that a typical racing rig is more complicated than a cruising rig, gives you more options, at the cost of requiring more ATTENTION, and making more frequent rig adjustments?
Very much! More that can be done to tune the rig means more that needs to be done to tune the rig. A simple cruisers rig is set-it-and-forget-it!
@@RiggingDoctor Thank you.
Well I am no expert and maybe I am entirely wrong but as I see it, the keel stepped mast would really only have limitations for adjustment because those movements would be made from the ends, the point of compression at the bottom and at the top of the mast, so to allow the movement to take place, the hole through the cabin would have to be large to accommodate the movement of the mast itself, which seems counterproductive. But as far as bendy-ness goes, I can see no reason why a deck stepped would be more bendy or substantially less stiff. If we are talking about masts of the same height, remember that the keel stepped mast is longer. In that case the cabin roof is acting as the "step" with regard to sideways movement, exactly as the deck stepped one is. They are essentially identical above the boat cabin. I suppose you are adding the material strength of the mast itself to that of the stays in a keel stepped mast but that strength is very low (when unsupported by stays) which is why it would be very dangerous to unhook your stays in the keel stepped. It just seems to me that any situations that could break stays will benefit very little from what little strength the unsupported mast might add but it does seem like a way to tear a gaping hole in cabin and another entry point for water. So, the two peices of spagetti are not the same length, the keel stepped one being longer to reach the keel...see what I mean?
While the keel stepped one is longer, it is still stiffer by having the attachment point at the deck. If you want to see this first hand, take two pieces of spaghetti like I did and test it out.
Cut one slightly shorter to be the deck step mast and keep one full length to be the keel step.
Hold the deck step one at the ends and push to see how much force it takes to bend it.
Now have someone hold the keel step version at the deck point and compress it. See how much stiffer it is!
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Practical reality is that, in lots of places, the choices of boats is not endless and you end up taking what suits you best, balancing all the vatious factors, then sailing her in a manner consistent with her design.
I'm from Australia and flew to Europe on a mission to finally enjoy life again, to buy a boat, learn to sail her and to see Europe. So shopping time was not endless for me. I originally thought "keel step or bust", but, on advice I remember fondly every day, I bought and old school, heavyweight Hallberg-Rassy with deck-stepped mast and before long, an episode solo sailing across the Bay of Biscay in 9 metre waves told me I have a wonderful, seaworthy boat - warts and all.
So, respectfully, I think you're discussing just one aspect of boat design and doing that in isolation doesn't mean a whole lot.
I assume you are talking about the beautiful Fair Isle and its epic journey through the Bay of Biscay.
It is looking at the point in a vacuum. It also doesn’t look at spreader direction, or additional rigging attachment. The goal was to cover just this one topic and not drown out the point with other information.
In the end, the boat is designed to sail as a whole, where all the parts compliment each other to create a wonderful machine that makes dreams come true.
@@RiggingDoctor wrong assumption. The video is about which mast arrangement is best but the practical reality is you mostly don't get to choose
I’m not sure I understand. If two otherwise identical boats have (a) a keel-stepped mast of 60 feet which the mast going through the deck at 10 feet or (b) a deck-stepped mast, then it would seem that the bending moment at the masthead is a function of the same loads (wind and rig tension) over the same effective length. Surely it’s the same as putting a finger on a guitar fret board to change the pitch of the note being played.
Bob_the_Bomb yes you are correct. What happens under deck in both is just compression
you certainly don't understand it, otherwise you wouldn't put the post.
the question should be: If I have two otherwise identical boats, where boat (a) has a mast attached to the keel (KeelStep) and boat (b) has a mast attached to the deck (DeckStep) ... so the lever caused by the force of the wind acts differently on both boats.
Kobudoka 11 that’s a very interesting point but quite different. If the point where a keel-stepped mask goes through the hull is strong enough, it could indeed act as a fulcrum, such that the forces on the upper portion of the mast could make the mast act as a lever acting against the hull in a way that a deck-stepped mast would not.
However we are discussing bending moments which are about the property of the mast itself. Not the same thing, though very interesting.
I'm not sure if I understand your question correctly, so my answer might be off topic. But here it is anyway:
First, since your question is technical, and you are asking about bending moments, let me make a technical correction. The bending moment IN THE MAST, is basically zero at the mast head (see Note 1). The bending moment in the mast over the length of the mast will resemble the sketch shown on page 12 (Fig 15-4, first sheet) of this PDF about beams:
www.civil.iitb.ac.in/~minamdar/ce317/Lectures/ApproximateMethods.pdf
It won't be exactly like this, because the loading is not constant along the height of the mast. But the rounded areas between attachment points, and the sharp points in the curve at the attachment points will be there, just at varying magnitudes.
On a keel stepped mast, this diagram represents a single spreader mast. Point A is the mast step at the keel, point B is the deck, point C is the spreader, and point D is the mast top. On a deck stepped mast, this represents a double spreader mast. Point A is the mast step at the deck, point B is the first spreader, point C is the second spreader, and point D of the top of the mast. Note that for both cases, the bending moment is zero at the mast steep and at the top of the mast. The big difference is that the keel stepped mast can have a bending moment at deck level, and this helps to stiffen the lower part of the mast.
I must note that at 5:15 Rigging Doctor is not correct when he says "you can never make a deck stepped mast as stiff" as a keel stepped mast. In his diagram, the two-spreader deck stepped setup would almost guarantee greater side-to-side stiffness in the mast. But, this comes with a caveat (actually, there are additional caveats -- but this is just a UA-cam comment, so I'll stick the the biggest one):
His diagram is for the side-to-side direction, so I assume this is the direction he was talking about. Typical spreaders and shrouds are very effective in the side-to-side direction. Fore and aft is a different story. In the fore and aft direction, the shrouds and spreaders usually have a limited influence. I could easily see a keel stepped mast improving stiffness in this direction more than a second spreader. Of course, you could add an inner forestay and running backstays for additional fore and aft stiffness. :)
Note 1: If the mast has a significant backstay crane sticking back from the top of the mast, then the backstay could impart a torque to the top of the mast, producing a modest moment at the top of the mast.
Andrew Snow thank you!
Question ? Something I’ve been working on? In the event of a knockdown? When the mast and sail fills with water and resist the righting action of the boat? Is it better to have a deck step mast that will break free allowing the boat to right quicker?
That is a loaded question!
If the mast breaks, now you have no spar to sail you home or protect you for the rest of the storm! Blue water boats tend to be designed to stay afloat upside down. Air can’t escape so water can’t come in and the boat won’t sink. Eventually, the weight of the keel will pull the sails and rig around until the boat can right itself.
If the conditions were that bad, you were probably already reefed so your smaller sails would hold less water and you should come around sooner than later.
I would personally prefer to still have the stick up when coming back because capsizing is horrible, adding a demasting will be devastating!
how about mast that bend under such tension but still survive? Something less stiff, more like a spring. Bent when overloaded and then returns to it's proper shape when forces are again within tolerance limits?
I'm thinking mostly about mast on tabernacle, and instead of avoiding capsize i look for design that make it less tragic. (There are already bridges in the equation - here comes the tabernacle, but since i'm going to "bow" my mast in front of the obstacle, why not "bow" it in confrontation with too big forces like rollover or failure to reef in time?)
we have a keel stepped mast but it is not attached at the deck, there is till room around the deck so it can stil bend at the deck
Sounds like it’s missing the wedges which would lock it in place.
Another great video. Always learning from you both.
Very informative. Thanks for the video.
I'm no expert, but I don't think it's a good idea to have a spaghetti mast. Imagine what would happen when the spaghetti mask gets wet. On the other hand, If you were able to carry a lot of tomato sauce...
🤓🤣🤣
🤣😂🤣😂🤣😂
my thoughts to
sounds about right...why did you say you were not an expert?
You are obviously not Italian! This is not a catastrophe rather an opportunity! Bring me your best sauce, don't hide behind the circumstances....
I absolutely love your video's explaining things.. Best on UA-cam
Thats a very high compliment! Thank you!
Always informative and easy to understand. Thank you.
Glad it was helpful!
Herb, your a smart guy for a Denist, thanks for all the information I did not know from a want to be sailor!
I would love to know your thoughts on a tabernacle set-up with mine by removing a single bolt I can rig a line to lift or lower the mast on a 34' cutter (sorry, I tried to add a photo without success)
If you are going to be deck stepped, a tabernacle is the way to go. You have so much versatility with that setup! On the Alberg project, we were going to do a tabernacle from a Westsail 32 to keep it deck stepped but instead we will be making it keel stepped since we are planning some big ocean trips.
You can email the pictures to riggingdr@gmail.com. I would love to see them as the bowsprit will have a tabernacle so that we can raise it up to save on marina costs.
Thank you so much for your reply I have emailed you some Photos of the tabernacle@@RiggingDoctor
Awesome explanation, easy and clear. Thanks
You’re welcome
I've got a tabernacle mast, it's about 43', because my boat was previously berthed at an inside marina in los angeles bay which is under/behind a bridge, but i've never lowered the mast. (I would try it, if there were a better/cheaper crane locally, but there's not, it would cost a couple hundred bucks of crane fees just to get a safety line to try it out.) Because of the tabernacle, the deck-step bracket is extra beefy, which is good, since the main complaint about mast safety on typical deck-stepped boats is that the mast rigging is compromised because of weak deck step hardware. In the ten years of having my boat I have yet to find a rigger who will help test out lowering it to the deck. Personally I figure the tabernacle is the best mast because lowering it allows easy work on the masthead or any other part of the rigging... if there is a rigger who can ever teach how to lower it properly! (duh.) Unfortunately the rigger who put on my synthetic rigging (colligo certified, and used dux) did not know how to re-rig for tabernacle properly, so he removed the various pelican hooks etc from the rigging, and made the rigging 'fixed'. So at some point I will have to rebuild the rigging release hardware so the mast can be lowered rather than fixed (duh!). One of the aspects of having the tabernacle, at least on my boat, is that the mainsheet is ridiculously long, almost 100', because the rigging which 'runs' the lowering is the main sheet, the mast falls forward, and the boom ends up pointing straight up in the air. I also hear from those who previously sailed a lot in the santa cruz area that boats somewhat regularly lose/break parts of their rigging during sails due to weather/swell conditions. Anyways, here's a question about mast strength. How much does installing mast steps weaken a mast? Because, a mast gets a lot of holes drilled into it for those steps.
About the mast tabernacle: in the book “The Riggers Apprentice” they give detailed information on how to lower a deck stepped mast (ideally one with a tabernacle) using the main sheet and the boom as a gin pole. It might be worth a read for you. From what I remember about it, basically the main sheet and topping lift support the mast on its way forward. Using preventers would help keep the boom going straight up as the mast leans forward. Raising the mast is just a matter of winching in the main sheet to bring everything back up.
Mast steps: while the act of drilling holes does weaken the spar, the mast step should help return that strength as the structure is strong and rigid on the side of the spar. Strength loss is not the big problem with mast steps, but weight aloft is. Try to get the lightest steps you can because their weight 10 feet up the mast will be 10x the foot pounds of your heeling. The steps at the top of your mast will exert the “height of those steps”x the original weight as foot pounds pulling the boat over when you are sailing.
The goal is to keep weight aloft to a minimum and you reduced a lot of weight by switching to synthetic, so it will never be as heavy up there with steps as it was while still steel, but the less you put back the better 😉
I say this because I have seen home made steps made from thick plate stainless steel that weigh a ton and also very light nylon steps that also fold out of the way. Adding steps is a laborious job so it’s ideal to do it once and as best as possible so “improvements” are not needed in the future :)
where can i find the blog post on this subject?
www.riggingdoctor.com/life-aboard/2020/5/20/deck-stepped-vs-keel-stepped-mast
Very good information !
On a modern cruising boat with a 50 foot mast height like used in the example, a deck stepped mast would likely be about 7 foot shorter then the keel stepped. You would have to break off about 14% of your noodle, then put your wife's hands (err simulated spreaders) back on the noodle and flex it some more. Some deck stepped mast even have crazy over built tabernacle systems that rival or even surpass the normal keel stepped systems in robustness (again with a shorter mast). They basically move the mast step to the roof allowing the mast to free stand, and place the weight on the compression post and bulkhead. The trade off is a slight shift in center of gravity for the boat (something most cruisers don't really adjust their lives for, IE jerry cans, random stuff on deck...etc), and the benefit is a source of leaking eliminated from the boat (water down the center of the mast or though the deck). My buddies tabernacle system allows him to use his anchor windless to raise and lower his mast (50 something feet) without a crane. As far as inside space trade offs, there is STILL a pretty massive compression post that takes up just as much space as a mast would in the salon. Good designers put the compression post in or on the bulkhead, god tier designers put the mast step in a shower :op
We’re going to be converting a deck stepped boat to keel stepped and that’s exactly where the step will go!
What about J and Farr and Jenn 3200 and 3600 etc. aren’t they all keel stepped? Thanks
I would prefer less holes in my boat.
Leif Mealone And give up the water collection feature? 😂 how about a big perforated deck plate. For stability of the mast, but allows rainwater to pass through. Below deck, have a split O ring and trough that is plumbed to the fresh water tank?
With respect regardless of where you sail (coastal or offshore) the advantages if a deck-stepped out weigh a keel stepped mast in a modern boat. Deck stepped masts are cheaper and easier to install. Easier to maintain as removal for repairs or winter storage is simpler.( so more likely to be done!). Safety for offshore keel stepped can do a lot more damage if you have a big problem! And that hole in the deck is always a leak issue. Racing or otherwise setting up your rig properly is important keel stepped restricts options of rake and pre-bend . Pretend is important in all rigs to minimize risk of mast inversion . Rake needs to be changeable in life of a boat for example if you change you sails to batten-less for cruising or get rid of those Huge overlapping sails from the 60’s and 70’s designs you may need to change the center of effort and rake is the easiest way to adjust that . Same as if you had bad weather or Lee helm issues. Rake adjustment is your friend.. But as you said maintaining what you have is your first priority ! Good subject Cheers Warren
_"Deck stepped masts are cheaper and easier to install"_
As someone who has stepped 100's of mast, this is incorrect.
Which is easier to work with, something that needs 3 points of attachment to hold it up while you are working on it, or one that will free-stand while you attach it?
Also there is no price difference between the two.
_"And that hole in the deck is always a leak issue."_
And if you do not think that a deck stepped mast has any holes in the deck you fail to understand that there are communication and power wires that need to be run and either one (mast step hole or wire holes) can cause the same leakages issues.
_"Racing or otherwise setting up your rig properly is important keel stepped restricts options of rake and pre-bend ."_
Literally the opposite.
Deck stepped racing boats have adjustable steps, deck stepped boats do not due to the fact on a keel you have room to move around and have a solid surface. On a deck stepped there is one spot that have been reinforced and as such you will not have an adjustable step like you would find on a race boat that is keel stepped.
@@bobbob6472 Thanks for your comments, from an installation point of view prehaps the keel stepped is easier from new but once that mast has been sealed into the deck numerous times because of the never ending leaks around and down the inside of the mast it will become a real pain. then dealing with the corrosion from the mast heel sitting in the bilge with salt water running down it , yuk! Yeah race boats that have their masts pulled all the time, it matters, not but cruisers will be leaving their masts up forever when keel stepped.
From a builders point of view deck stepped is easier and quicker to build.
Of course there are small holes around a keel stepped mast subject to leak maintenance but the huge hole from the mast and the internal leaks. Deck stepped every time. Besides why run all those wires thru the deck when a good design could bring them back over the deck in a tunnel , like all the running rigging everyone loves to run aft these days and feed then below in a more protected spot.
Re adjust-ability of rake etc , once somebody has sealed that big cruising mast into that huge deck hole with their favorite cured sealant for the last time (they hope) the last this they want to be doing is playing with rake to break that seal! Sure keel stepped masts on race boat have all kinds of adjustment options to effect rake or heel position but they don't care about a little salt water down below on the cushions or fabrics!
For the regular cruising boat or so called blue water boat deck stepped every time in a properly designed mast step.
i know you will disagree but there you have it from a not racing user point of view.
oh check other comments about leaks form deck stepped masts , there are quite a few!
cheers warren
Do you have a video on rod rigging vs wire? If no can you make one?
That is a good topic! I don’t have a video on it yet but I will soon ;)
Thanks for the idea 👍
I have a question rigging doctor is there a crimping tool available that you can keep on the boat to crimp ends on in case you are where you can't get it done?
The hand operated machines are rather weak and not very dependable, even for lifelines! The proper swage machines are rather large (and expensive).
What would be a patch in those situations is being able to tie a small piece of Dyneema to the end of the broken stay, either with three flat seizing knots in a row or a single icicle hitch. The other end of the Dyneema can be tied to the other side of the break so you can keep going. It’s not great but it’s doable.
For this reason, they sell “synthetic backup stays” that are marketed as a “spare tire” in the event of a broken stay in a random place. They are light and store easily, and best of all, being rope they can be easily modified to fit the intended need at that time.
The short answer: No
The real answer: when you find yourself in that situation, you will find something that will make do and you can sail home (but having a keel step mast would help reduce the absolute reliance on the rigging as the mast deck interface would impart some much needed stiffness and support to the broken equation).
@@RiggingDoctor thanks good info! !!
Can you make a video of mast VS keel placement
That’s a great topic! Will do 😉
@@RiggingDoctor like is it good to center the mast over the dagger board, or to move the mast forward and the keel a bit back?
I really love this channel, it is so informative! Thank you..
Thanks!
🤔 Another advantage of a deck stepped mast is the ability to self-step the mast on water or at the dock. A keel stepped mast requires the logistics and expense of crane services.
We had a 19’ West Wight Potter and became adept at stepping & erecting our mast underway to navigate past the low bridges thru Florida’s rivers and canals interconnect the lakes. This of course requires calm weather, no lightning, and a skilled crew.
Other applications to this scheme would be the Erie Canal, Inter-coastal Waterway, Canadian & European canals and general passage thru estuaries which have overhanging tree branches. 😎
You are incorrect calling the "deck to mast interface" a support. It is suppose to have clearance from the deck entrance to the mast wall. Secondly a deck stepped mast is shorter than a keel step making it less "noodly". Whether deck or keel, the shroad attachment points, mast to chainplates are the same.
The hole where the mast slips through is supposed to be wedged right with wooden wedges driven in between the mast and deck, making it a secure interface and point of support.
@@RiggingDoctor this of course make the need for keel stepping pointless. keel stepped racing boats have they place for weird race boat reasons and the don't care about water below decks. if you going to make the keel stepped mast ridged in the deck hole then just leave it on the deck, and movement or flex will cause more leaks , problems etc.
Nice video helping us all understand why boats are different. Small issue I seem to think the Merlin Rockets (dinghy show) are keel stepped or the ones I sailed were. Mind you dinghy mast are incredibly flexible.
Very informative, love these videos...
It does not matter keel or deck as long as the mast is tune properly with a loos gauge . I've seen more keel stepped masts snap then deck stepped . Having loose rigging as you did Herby with your dimenna rigging is an accident waiting to happen ,allowing mast pumping and eventually snapping
My mast never pumps. If I had a deck stepped mast, it would have fallen with my loose rigging. Being keel stepped, I can have the rigging set looser because the mast deck interface grants me more stiffness and that means less wear and tear on the boat.
Think about it, which boat is going to break first? The one under incredible rig tension or the one with relaxed rigging?
You are aware that a Loos Gauge only tells you the tension in the stay, not how to tune your rigging. When working with older or custom boats, there is not paper that tells you tensions. It’s all by feel!
The reason you see more keel stepped masts snap is because the deck stepped mast fall over completely! Deck stepped masts are so reliant on their rigging that any issues lead to a dismasting. On a keel stepped boat, the mast is intuitively stiffer and therefore there is some leeway in what the rigging does.
Deck stepped rely on rigging. Keel stepped are helped by rigging.
What about a lower pivingpoint?
On deck stepped masts, they make it really handy to raise and lower the spar for going under low bridges :)
When it comes to bendy masts it also depends on the mast section and if is tapered. Fractional mast rigs are often tapered with no cap shroud so the top section is very bendy regardless of whether it is deck or keel stepped. Not quite as black and white as portrayed in this video
Tapered masts are more bendy than constant cross section masts, so if a tapered mast is deck stepped or keel stepped, it will still be more bendy that a mast that isn’t tapered, in the same deck stepped or keel stepped situation.
To have the stiffest spar, a keel stepped non tapered mast would be the way to go. For the bendiest mast that would be the most adjustable, a tapered deck stepped mast would be your race winner!
What changes have you made to the rigging? Just rewatched the video with the shroud frapping knot.
The rigging design: I added a backstay adjuster in the split backstay so that I could more easily tweak the headstay tension.
I replaced the steel stays with synthetic and deadeyes instead of turnbuckles, but the angles of the stays and number of stays is still the same as it was when I bought it.
Being a cutter, it has some “extra” rigging to support the staysail. This includes the inner forestay and two check stays that act as backstays (to a limited degree) and shrouds for the inner forestay.
This gives our boat the benefits of an extra point of attachment 3/4 up the mast without the complexity of a second set of spreaders. It also keeps the first spreader at the 1/2 point of the mast instead of bringing them down, so in the event of the mast breaking, we will have 1/2 a mast instead of 1/3 of a mast.
I wonder how many spaghetti noodles died in the making of this video...
About 8! 🤣
Why does a mast usually break at the lower spreader?
By the way the A frame is really interesting as a possible alternative to a centreline mounted mast
A frames are also better for the air flow over the sail!
The break at the first spreader is because the lowers attach to the mast at an broader angle. From there up, the stays need a spreader to get them far enough out so that the stay reaches the mast at the proper angle, and any issues and the efficacy of the shroud vanishes.
If you look at pictures of mast breaks, they are always at the first spreader, be it single spreader or 7 spreaders!
V good info. Bests
Searching for alternate mast tracks, come across this. Great topic & info! also love the nails on your 2nd pair of hands 😜Guess u had Italian for dinner. My guess would be, every spreader creates a weak point, due to drilling holes in the mast. Pros & cons to both, but I prefer keel, plan interior around it.
For mast tracks, check out Tides Marine. They are awesome. I have had it for over 10 years and never had the slides get stuck.
Questions: Why do you throughout the video show a picture of a compression post for a deck stepped mast every time you mention a keel stepped mast?
And why don't you mention that keel stepped masts always leak?
I've had both, and I certainly know what I prefer. And it isn't a keel stepped mast..
The compressive load of a deck stepped mast is transferred through the boat most commonly by a compression post. It is much smaller than the actual spar giving more interior space but it is still common which is why I show the compression post.
As for keel stepped masts, they don’t have to leak if you seal them up properly. All you need is some mast tape or a mast boot and water will stay out of your hull!
The important part is that you have a mast setup that you like and can maintain :)
@@RiggingDoctor Water will always come in through the mast itself. No amount of collars can prevent that, and sooner or later the internal waterproofing of a mast will fail and be impossible to fix. I have yet to talk with someone with keel stepped masts without water ingress through the mast. Admittedly it is not much water that comes in, but you can forget having a dry bilge if you have a keel stepped mast.
Anyway, you misunderstood my first question. I am well aware of the physics involved, and if I stretch out my hand I can touch my own compression post. I was wondering why you showed a compression post when you were advocating for the benefits of the keel stepped mast, instead of showing how large they actually are. (at least on boats above a certain size- say from 35' and up) As you say, they are much larger than the post, and in most cases are free standing. The worst case I have seen is one that goes through the middle of the saloon table so you have to look around it to see people on the opposite side. :)
Yes, a small amount of water can come in from the halyards and their ports in and out of the mast. We have a dry bilge but our mast and mast step are located in the shower where the shower sump collects the water and sends it out. I guess mast leaks and shower water all look the same to me in that sump!
The pictures I showed were of salons of deck stepped and keel stepped boats. The rather small looking mast that might be confused with a compression post is actually the mast and interior of a few different sailboats that has horribly central masts in the salon.
I tried to show the worst mast because it can be better. Ours for example is in the shower, so you never see it and any water that comes in goes into the shower sump. But if I show a hidden mast, it doesn’t drive home the fact that the big spar is going to come into the boat 🤪
@@RiggingDoctor Sorry Sir. Not buying it. That post is circular. Are you going to tell me that a boat that size (must be 4m/12' wide, suggesting a length >40') has a 10cm/4 inch diameter round mast? What boat is that picture from? Also that because you happen to have a boat where the largest common drawbacks of a keel stepped mast have been successfully solved, you forgot to mention them? No, Sir. Not plausible. You are of course entitled to your opinion, and you have stated it in your video. It is the fact that you apparently seem to be unbiased when what you actually say and show tells another story that I am reacting to. Both methods of stepping a mast are perfectly fine, and each have advantages and drawbacks. Your explanation however, is lacking and I wonder why.
You are correct! I made a mistake with the picture. It’s a Catalina Morgan 45 CC and it is a compression post coming down the middle of the salon! When I was searching for horrible salon layouts I didn’t do enough homework to make sure it was a mast and not a compression post 🤦♂️
I tried to present the information as information so that viewers can make an informed opinion on which boat they want to buy. I personally own two sailboats, one is keel stepped and one is deck stepped.
One is a boat I feel comfortable on in the Chesapeake Bay, and the other is one I feel comfortable crossing oceans with. The comfort is more based on the size of the boats as one is 30’ and the other is 45’. If properly tuned and maintained, both work just fine. The difference is what happens when things go really badly out at sea. I’m personally more concerned with spreader count over mast step location.
Not nit picking but the photos shown for the keel stepped mast are actually showing a compression post.
Yeah, I realized that when someone pointed it out. It’s the interior of a Catalina Morgan 45 CC. When I was searching for photos I just saw the giant poorly placed post and thought it was the mast but it clearly isn’t. 😕
I need to make that correction, but it does showcase how annoying a mast would be in the middle of the salon!
@@RiggingDoctor my keel stepped mast is in the middle of a bulkhead so not so intrusive. If I could work out how to include a photo I would!
Do you have a book on synthetic rigging
Not yet 😉
I have read the article in a boatbuilder`s magazine that the deck-stepped mast more suitable for the cruisers and the keel-stepped mast for the race boats because the deck-stepped mast usually more heavy (the mast is more thickness) and it is not possible to bend for flatten the main sail when stong wind. The keel-stepped mast is more thin and light and easy to bend.
Well, the right answer is that it depends :) Yes, a lot of raceboats have keelstepped mast, but far from all. It all depends on how the rig is designed.
Even deckstepped masts with potentially thicker sections can be easily bent while sailing, if they are set up for it.
I'd say that masthead vs fractional forestay make a lot more difference in how and how much you can bend the mast than wether it's keel or deckstepped.
Some yachts I've sailed with fractional keelstepped masts had masttops that bent like semicooked spaghetti when you crank the backstay, and some keelstepped masthead boats had basically no way to adjust mastbend during sailing.
You miss one of the main advantages of a deck-stepped mast: portability. If you are going to be setting up and taking down your rig, the deck-step makes life so much more simple. Trailer-sailers are all deck-stepped for obvious reasons. If you're going to be doing canal-transits that require your rig to come down (the Erie Canal, or the Tenn-Tom come to mind), the deck-step is so much easier; the keel-step will require a crane in most cases to get the mast high-enough to get the mast in and out. Like anything else, you need to know what you want your boat to do.
That is a very good point!
My boat is keel step .. but the deck does not support the mast .. even not under sail.
You can run your fingers around the hole. ( we don’t )
The mast moves a bit in the hole but it hardly uses the deck structure for stiffness
Sounds like your mast wedges have rotted out and fallen away. All you need to do is cut some white oak into wedges to wedge your mast again.
Check out this post that goes over how to wedge your mast properly: www.riggingdoctor.com/life-aboard/2016/2/29/wedging-the-mast-deck-partner
Wow.. this was great. I am looking at sailboats. This was very helpful. What do you think about using a drone to check your standing rigging versus going up the mast?
You can’t replace the value of going up the mast, but if it’s for minor checks, drone is good! We use it sometimes for that purpose
What about racing boats say they are made with sitka spuce masts that are keel stepped sa my boat loa is 41' with a 60 foot mast and and a 22 foot boom and you would say this is a cruiser or racer yes I know this is not a newer built built boat but at the same time this boat carts 740 sq ft on main and 240 on jib sail .with a spinnaker she runs a total sq footage of 1550 sq ft she was built as a racer that could cruise with a bendy stick and usually would move on about 9.5 knots of average speed comfortable as can be probably not but for a boat from 1936 what would you expect
I love your teaching videos
Thanks :)
Good job with this topic. Can you post a link the blog post you spoke of?
www.riggingdoctor.com/life-aboard/2020/5/20/deck-stepped-vs-keel-stepped-mast
How are the chainplates coming along?
They’re all fixed! It wasn’t too bad :)
@@RiggingDoctor Excellent, very happy to hear it.
With displacement hull the speed is determined by hull design but mostly by length. Weight should not play a very large role overall.
Not the speed, but maximum speed. The question is how fast you get to the maximum
Very true. We will sit still in a light breeze weighing 18 tons while a much lighter boat will be approaching hull speed. They get places fast all the time where we only start moving in a small craft advisory.
That makes sense.
Something you didn't address is that a keel stepped mast can be a lot lighter, thus giving you the same sort of "bendiness" as a deck stepped mast, which is important to racers. I have a 30ft IOR boat with keel stepped mast, and two people can pick up the 50ft mast. My friend's deck stepped mast for a boat of similar size takes at least 4 to pick up.
My boat is also fractional rigged which gives me terrific control over the main sail shape, another important thing for racers.
That is a very good point and your setup gives you incredible tuning ability!
Sorry. Lots of misinformation here. In my experience, the majority of racing sailboats have keel stepped masts. High tech race boats may have a hydraulic jack underneath to adjust the rig tension. The compressive forces on the rig are substantial. Whether or not your mast is deck stepped or keel stepped, is not really a factor in bending the mast to the desired shape. Either system properly designed can do the same thing. Your pasta analogy fails. You should not be comparing 2 lengths of pasta that are the same. You have one that is the added length of the below deck portion. If you held the pasta at that intermediate point, both now the same length, they have equal stiffness. More bendy mast sections do need more sets of spreaders to keep in column under load, but being deck or keel stepped doesn’t change that.
A deck stepped mast is more bendy than a keel stepped, and on yachts that convert from keel stepped to deck stepped, the entire spar needs to be replaced with one that has thicker walls because simply cutting the bottom off and stepping it on the deck will yield a mast that is way too bendy.
Having that added point of contact between the deck and mast adds a significant amount of stiffness which lets the mast be made of a thinner walled material for the same mast height (bridge clearance).
The premier ocean racing class TP 52 has a keel stepped mast and plenty of ability to control sail shape with bending. From J boats, C&Cs, Swans, Baltics, Tartan have keel stepped masts and are actively raced. It all depends on how you design it. it might be interesting to invite a designer into this conversation.
Actively racing a blue water boat isn’t the same as a purpose built race yacht. Pogo and Beneteau First are deck stepped with racing in mind.
At the same time, VOR Open 70 was keel stepped, allowing the mast to be very light because of the added rigidity that comes from the mast/deck interface. To get the mast bendy enough, they could make it thinner and lighter which is wonderful on a spar that is over 100 feet!
It all comes down to what the designer wants and the purpose of the yacht. In the end, deck stepped masts are bendier (so they need to be thicker to not be bendy) while keel stepped masts are stiffer (so they need to be thinner to be bendy).
@@RiggingDoctor Beneteau first deck stepped ?? Not anyone I've sail and stepped the mast all keel stepped 36.7, 35.7, 375, 38, 45.5 all keel stepped even mumm farr racing boats are keel stepped and I have seen them demast
From an Engineering point of view the deck stepped is a stayed, simply supported beam, the keel stepped is a stayed, cantilevered beam. The stress patterns in both are very different at the level of the deck. There is no right or wrong, just that they are designed differently (or should be!)
Great informative video ,,nice job
what about tabernackals
They are the best part of a deck stepped mast!
Those two magic hands were hilarious, that is what I will say about that. 🙂Three years later.
You did an excellent job with your explanation, Herby!
And all of this is not absolute as you said. We race in low PHRF on the most visited USACOE lake. Last year we were top boat for the year on a Flying Tiger 10 meter. It's keel stepped. But it is also fast. Mast, boom and rudder are carbon fiber, double spreader on a 33' boat. But we win on the I dimension.
That is a very impressive setup! Maddie gets mad when I start drooling over racing boat rigs. I think she’s worried I will convert our cruising boat and that would mean more work when underway 🤣
@@RiggingDoctor The FT 10 is an awesome racing boat. We are considering an offshore race this year. But I would never want to cruise on a racing boat. There are more lines and controls than I would want to deal with while cruising. Vang, Cunningham, Coarse and Fine Mainsheet tuning, constant backstay adjustments, weight on the rail, off the rail, on the leeward, back to the high side rail. There is never a relaxed moment when sailing this boat. Absolutely no opportunity to read anything except the race course - NO! Starboard on this rounding! I was only commenting on the fact that it's keel stepped as a race boat. I'm looking forward to an Amel Super Maramu, Oyster 485, or Swan 50+. There is nothing like offshore with steady wind.
Great explanations
Thank you!
Really enjoyed the explanation , simple yet very well done , the spaghetti analogy is genius , from a landlubber with dreams . . . . .
Most production performance yachts are keel stepped, and most cruising yachts
Because they are better?
@RiggingDoctor So maybe you should re-record your video with this correction 😉
Great Video! I love when you tackle the physics of sailing, but I'm confused.
If the length between the deck and the mast head is the same in each case, then shouldn't that spar have the same flex points no matter if it is fixed in a deck step or securely fitted through the deck? If the keel-stepped mast is securely fixed at the deck, then the below-deck portion will not aid nor hinder flexing. It is out of the equation entirely.
Isn't this like a capo on the neck of a guitar? The vibrations (bending) in the strings stops at the capo. Wouldn't the deck fitting work the same as a capo on the neck of a guitar, and stop all bending below the level of the deck? If so, then a deck-stepped mast, and a secured deck-fitting on a keel-stepped mast, should work the same for the same length above decks.
In your example with the spaghetti you are bending the spaghetti with BOTH hands around the single or double secured spots (supplied by your wife's hands), but in reality the end of the mast down in the keel is not under sideways force. All the side forces exist from the deck upwards to the mast-head, so all the matters is the length of the mast ABOVE the deck.
There ARE downward compression forces which might be better to be loaded onto the keel vs the deck, but there are no sideways forces below deck. What am I missing here? Great Video! Thanks for all your effort.
Similar thought.
The keel step mast is longer than the deck step mast. It is longer by the length from the keel to the deck and 'would' experience more torque if not for the deck. Provided the attachment point on the deck is solid, the applied torque providing lateral shear force pivots at the point of the deck and headmaster. In other words, The forces above the deck are equal between the 2 setups and everything below the deck is part of a different equation - eg: if u have no shrouds at all.
Does this sound right?
@@DarenSpinelle the deck is effectively another spreader on a mast that is "keel step to deck" metres taller, and in most cases you can treat the deck as being infinitely strong (not really, but for purposes of accuracy when the mast is represented by pasta :) ) you can get _some_ bend between deck and keel, consider the deck step acting like a pivot point, or the fulcrum in a playground see-saw. As practical example, place a ruler flat on the table, with a few most of it hanging off the edge, and a few inches on the table - hold in place with a finger tip on the end, and at the table edge - now bend the free end of the ruler down, you'll see the ruler lift a little off the table.
quick _dry
I agree with that.
I think my question came down to; does a keel step allow you to use a thinner/weaker/lighter mast and achieve the same 'strength' (keeping everything else equal- width of spreaders, height of mast head, streamers etc.)
@@DarenSpinelle yes... but with some hand waving :) . The mast section has to be strong enough to resist the bending in each panel (from spreader to spreader) thus more spreaders = less bending, but it also has to resist buckling under the compression induced by all the rigging. My understanding is that this is part of why an oval section works for a mast - it has all the spreaders to make small sections in the transverse direction - but fore and aft, you don't have much because it'd interfere with the sails - it's one unsupported section from deck to headstay.
If you see the equation for a buckling column, the coefficient for a column pinned at both ends vs a column pinned at one end and fixed at the other, the fixed end column has more advantageous coefficient - i.e. lighter mast, though diminishing returns as the mast length grows.
There are some good discussions on deck v keel step over on boatdesign dot net with input from longtime professional boat designers. Alternately, it should also allow for less loading on the rigging (or a higher safety factor depending how you look at it), or lighter rigging - same with using a wider shroud base
The comments below were very good in exploring the point.
While the bottom doesn’t twist, it is part of the compressive force on the spar which will cause the mast to bend. The force is all pulling down, but the mast doesn’t know that it’s being pulled down onto a solid mast step. It just sees itself in the middle being compressed from the top and bottom. When it bends from a compressive force, it bends regardless of which side is being pushed.
Having more points of attachment makes the spar “stiffer”. This means that a deck step mast will always have one point of attachment less than a keel step because it doesn’t have the mast/deck junction and therefore will be bendier. As a result, a deck step mast (with the same bridge clearance as a keel step version) will have a shorter mast but need a thicker walled mast to give it the needed strength.
Sorry mate you’re wrong, a deck step mast is fixed at the deck and therefore the same strength as a keel stepped mast.
Fractional rigged masts on the other hand are a completely different story.
I think you should give the spaghetti demonstration a try. Keel or deck, fractional rig just allows more force from the backstay to tighten the headstay. They tend to be deck stepped because they are bendier and therefore easier to bend and get that tension on the headstay. Keel stepped are just stiffer by nature.
Give it a try, it will blow your mind!
Sorry but you are incorrect in your assumptions. You show Volvo boats as examples of deck stepped as being better... They aren't keel stepped because of the location of the canting keel box. Imocas have rotating masts so again deck stepped. Secondly all these offshore race boats that are deck stepped have carbon bulkheads with zero space inside as the boat translates it's stiffness directly to the mast connection.
Even that's not the end of it as tp52 is canting and keel stepped mostly inshore boat. Wild oats xi is keel stepped canting offshore. Comanche it's competitor is deck stepped because they wanted to make it with uninterrupted carbon stringers...Third all these boats have running backstays at the hounds as bending your mast and driving lower sections forward is slow. You want to bend the top section only in sail trim...Better to ask Bruce Farr than Mr spaghetti.
Regards
I think you missed the point. He was explaining basics not getting all up into racing. Now if you want the guy to spend 4 or 5 hours to teach ever aspect, send him more then a piece of pasta to show the demo with and then he might consider your input on the level of teaching. I get all the point he made,, Anyone else?
Racing boat do lots of weird things for lots of weird reasons as you point out. they are not good examples for a subject about and for cruising boats and cruising people.
Too much going on ( BS ) for a newbie.
Sea U in a year or so when I have a little more under my sails.
All information is good information for someone who is learning. Thanks
These days, aluminum masts seem to be the usual. A wooden mast behaves much differently under load. 'Once upon a time' back in the 70's, I built a Herreshoff three mast schooner, I built the spars of spruce....11+ growth rings per inch. Unlike Aluminum, a wooden spar can go a bit out of column and live, aluminium MUST be kept straight. Personally....I would be very loath to sail offshore with a deck stepped mast of any sort. We once spent a week in the westeries blowing 35-40, boat speed around 8.5 surging to 9 now and then, 15 foot or so swell....so calm in the troughs. I'm 75 now and still miss living on the water. -Veteran '66-68
Hi Doctor...Good explanation...However you totally left out “loaded vs unloaded” rigs...deck step = always loaded. Keel step can be unloaded with grid and vastly better for performance and boat wear....Thanks and I look forward
Very true, I keep my Rigging on the looser side of life to reduce the amount of wear and tear on the boat. With a deck stepped mast, my rig tension would lead to catastrophe!
that sounds scary! there is nothing about a keel stepped mast that allows you to have a looser rig . You will just put unintended stress on the mast at the deck opening , potentially leading to failure and a mast over the side with a large hole in your deck! correct tension is your friend.
WARREN MYNAME there is a difference between correct tension and high strung. If I had aft swept spreaders, high aspect ratio sails, and inboard chainplates, my rigging would need to be very tight to be safe (deck or keel stepped).
Having a lower aspect ratio, lateral spreaders and chainplates on the edge of the deck, the loads are lower and so is the rigging tension.
I’m not saying that the shrouds get tight when the mast leans over, but when the mast is straight they have a little play in them, and instantly load up when they have wind on them. The leeward shrouds also go loose in winds of 25 knots as they should.
Low stress and low loads make the boat happy but tight enough to be safe.
Rigging Doctor Agreed , with a wide rigging base the tension can be less. As you know you only have to look up the mast to see what’s going on when you are cranked over with the rail in the water to know if you have it about right.
That’s also why catamarans can have such relatively loose rig tension the wide base.
Cheers Warren. Ps defiantly a contentious subject!
warp21drive whenever we are under full sail and heeling about 20*, I go forward and take a peek at the mast to make sure it’s in column. I know I keep the rigging on the slacker side of things because less load means less stress on everything! I also know that toeing the line means that I need to check if the mast is doing alright. So far, for the past 3 years, the mast has always been in column when I look up on either tack.
Low strung life for me! ⛵️
Is the mast on Wisdom made of wood or aluminum?
Our mast is Aluminum
My sailboat is located on a lake (Oneida Lake, NY). I have owed both styles of sailboat. If I want to travel to the great lakes or to the Hudson river I have to take my mast down. Much easier on my deck stepped sailboat. I never have a wet bilge. Having an extra 6 or 7 feet hanging over the boat is not fun when traveling with it down. If the rigging is inspected properly and replaced every 15 or so years I see no reason to shy away from a deck stepped mast. I have found that things fail when they are past their useful life or not maintained. If you are in 40 knot winds on a 35 year old sailboat that was kept in saltwater its entire life with original rigging it doesn't matter if it is deck stepped or keel-stepped its only a matter of time.
On a different note. I see lots of conversations between what is considered blue water and not. Blue water to me means very well maintained (Replace things on a schedule and not wait for them to break, inspections, maintenance). I would pick a very well maintained Catalina to travel across the Atlantic over a not so well maintained Hans Christian or Hallberg Rassy. I've been on a few blue water boats that I would not take out of the marina.
I think new sailors get hung up on terms and less on the condition and maintenance. I did when first looking into sailing.
agree 100%. and those keel stepped masts that never get removed and corrode away in the bilge , just waiting for the first big blow and the mast base to crush a little , rig goes loose, swaying mast and momentum causes an overstessed mast and it lets go leaving you mast less in a storm with a huge hole in your deck!
there are various examples on YT of people buying an old boat and finding the keel stepped mast below the floor in the salt filled bilge half rotted/corroded thru! put my mast where i can see it every time! every day!
what about pointing? Deck stepped v mast stepped?
Pointing is more affected by the sheeting angle of the sails. If the headsail is sheeted to the rail, it can never be trimmed in as tightly and will not point as high. If the sheeting point is in on the deck, then the sail can be sheeted in very tightly and point significantly higher. The limiting factor to this is where the shrouds attach, as the Genoa needs to sheet outboard of the shrouds. Boats with shrouds attaching at the side of the hull won’t have as tight a sheeting angle as boats with the shrouds very inboard on the deck, and thus a much tighter sheeting angle.
Consider that if a keel stepped mast fails you essentially have an eggbeater below decks as the mast thrashes about...
I’m not sure what you mean by an egg beater below deck, but you will have a hole in the deck where you can stick the boom to jury rig a tiny mast (as long as you still have a boom)
Deck step or keel step..... it also depends on wat kind of material you Hull is made of, I would never advise a keel step on a steel boat.
Danged fat fingers. Unless on specialized racing craft, deck stepped masts must either have heavily reinforced decks or a compression post to carry the weight and thrust loads of the mast. The handiest means of attaching the mast to the deck is via the venerable tabernacle, which allows the easiest method of initial rigging, periodic maintenance, and emergency non-assisted repair to the mast. It helps when you meet that low bridge along the way, too. Laying the tabernacled mast aft into jury-rigged or permanent crutch, using the forestay and spreader or whisker pole to keep a good angle, is such a simple matter. As to reconfiguring those pointy-headed sails onto a shortened mast, I recommend you research gaff, lug, and sprit rigs as options for emergency rerigging. Compared to your original elegant pointy sail rig, they are not as efficient, but they are certainly more efficient than the emergency low aspect ratio sail rigs your photos show. Old timey thinking here.
I feel like your example is incorrect. The two masts (pieces of pasta) will not be the same total length. Mast length is about height above a boat. If deck-stepped mast was 30 feet tall (and thus 30 feet above the deck) and the architect decided to make it keel-stepped then the mast is not now 20 feet above the deck. In other words, you should be comparing a 10 inch piece of spaghetti with being pinched at 3" with a 7" piece of spaghetti. Right?
Mast length is different from mast height.
Mast height is the height above the deck that the mast sits. Mast length is the cut length of metal for the spar.
If the mast height is 30 feet, then on a deck stepped boat, the mast length would also be 30 feet. On a keel stepped boat, it might be more like 40 feet, since it has to go through the deck and interior to rest in the keel.
So you would be trying two pieces of spaghetti, one longer than the other, but both held at the same points (with the addition of the end being held on the longer one.
Say on a 10 inch piece, held at 0” 5” and 10” (deck stepped)
On a 13 inch piece, held at 0” 5” 10” and 13” (keel stepped).
Give it a try, the difference is remarkable!
Same distance from cabin top to top of mast no matter if its keel stepped or cabin top stepped, so should bend the same.
The section inside the boat on a keel stepped mast gives the section from the deck to the masthead more rigidity due to the support from the mast passing through the deck.