Designing our Catamaran Rudder Mechanism // Catamaran Building Project Ep264
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- Опубліковано 5 кві 2023
- Building a Catamaran can be a lot of thinking and not a lot of building. To design and install a rudder system isn't quite as easy as you think. A rudder is a simple piece of equipment that creates resistance to steer the boat, it could be as simple as a piece of wood, a barn door or a piece of foam encased in carbon and in Designing our Catamaran Rudder Mechanism I have found some challenges that require research, more space, and the engineering know how to ensure it will function smoothly in the worst of conditions.
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Action packed episode Rosco! "Under certain circumstances, profanity provides a relief even denied to prayer." -
Mark Twain
Hah.I love it mate.You and I are such boat building bro's.
When I installed the autopilot ram on my boat I had the same concerns about losing storage in my lazarette. I ended up building a removable cover to go over the mechanism to protect it and to prevent gear I tossed in there from getting tangled up with it. It cost a bit of space but the peace of mind was worth it. Just a thought that might help your ram situation. Great episode as usual!
Artisan work!!!
Killin it.
Hello Rossco. On your Tiller Arm just add two Arm plates of Aluminum to make it Longer so you make a Sandwich, then your Hydraulic Ram Can be Mounted on the Side of the Hull . No shelves needed. On the Rudder post do the angles Fiberglass on four Sides the a shelve on the top to finish the Support. Please make your Rudder out of Carbon/Kevlar Fiber incase you get Attack by Killer Whales or hit a reef. Hehehehehe . I like Kevlar fiber only. Happy Easter to you and Wifely.
Top job Ross. Getting closer by the week. Awsom job mate. Cheers
Thanks John. Appreciate you watching buddy.Ross
If you want a longer tiller arm, take the short arm you have to a local foundry and see if they can cast you a longer one.
You have the option to redesign it without a key way and clamping bolts. I recall you were going to pin the rudder shaft to the
tiller arm anyway.
The moment you said jammed/log jammed I was putting strawberry jam on my brekky muffin.
If the tiller arm was longer, it would offer a higher mechanical advantage as well as allow the piston to be mounted on the hull side. She's looking good.
Brilliant
Cheers Rosco
Thanks Bob
You need a bit of foam to sit on mate, you don’t want to get in dingleberries hangin out ya clacker 😱🤣🤣🤣
Happy Easter painting🤙🏼🤙🏼
Thanks mate.Plenty of padding on my bum. Cheers and happy Easter.Ross
An excellent bit of cobbliing in my opinion. Maybe sculpt it into 2 mermaids holding your tube
😁
Hilarious
10:49 you could also have someone fabricate you two plates that use that raised oval boss to sandwich the thing and extend the position of the ball joint. That could also be a means to have it be adjustable (multiple holes). Bonus: if it's done that way, the mounting situation will be much more streamlined, because instead of bolting to the top (or bottom) of that arm, the ball joint is mounted in line, between the two plates.
IMO, there's absolutely no issues on strength if you do this.
also 12:00 A yoga ball wrapped in some discard cloth bags should make life easier for you.
Would it be better to get a longer tiller arm fabricated out of stainless, aluminium or even a carbon fibre combination. That way you would have greater laverage and you would be able to set up the correct geometry? You could get a spare one as well for emergencies.
Then he would need a longer piston in order to still swing the rudder 35 degrees each way.
What might look awful now, will be stunning when finishes.
Your attention to detail will shine through, as always!
Thanks for sharing.
Thanks so much Leon.
Hi Rosco , It’s not the Australian way if you can’t bodgy something up , That’s what we do here in Australia. Keep up the good work love your videos cliff up in the real world. Logan City Queensland Australia 🇦🇺 we are on the big island 🏝️
Thanks 👍Cliff, happy easter mate.
Tiller arm extension possibly?? You could extend our as far as you need! I think it may be very important to maintain 90 degree push pull from nuetral to avoid more action one way than the other! You keep the mechanical 90 degrees hook up to have symmetrical action! You could end up with more throw one way and less the other! That could cause dual rudder throws to work against each other!Stresses could come into it too!! Oh and the longer the lever the less power needed to push and pull and also a softer feel in the steering due to the longer throw!
Amazing work Ross. I don’t know how you know all this. An amazing job and so interesting to see how you make it all.
Ohh thanks mate.Niw get on the road and have a brilliant time and forget about boat building.Happy Easter.
Mate you have to put a propeller strut in your shaft configuration. If you put that configuration on an airplane imagine the wobble you would get with that long shaft sticking out. You will get the same thing on a boat. Different liquid same result. I am sure you have taken it all into consideration. All the best and good luck. I think you are both amazing. If you ever get to The Bahamas give me a shout.
There is only 100mm from end of boat to prop housing.Strong as hell.No strut required.
Having seen how rudder collisions punch them through the hull, I'd want solid glass fore and aft of the rudder post and a bulkhead in front.
You are right to use Standered consumable parts. 👍🏼. Just me but that rudder looks small? I am sure it is the right size. Have you ever thought of making that rudder fold upwards if it hits a river bed? If possible might be worth thinking about doing that. Rudders always break when boats bottom out.
Very nice Ross.
I like the way you make the rudder tube/bearing.
And never mind the foam block, we all know that you will make it look the part after some shaping of it 😉
Take care mate, and have a greate weekend.
All the best.
Looking good rosco
Don’t know if you have looked into the rudder sleeve you mentioned in the vid but carbon fibre and aluminium will create a galvanic corrosion situation
A stainless steel sleeve would be a better option
Keep up the good work love the videos even if it is something I do for a living it’s good to see the different ways someone else does things
I always heard the fix for that was to put a layer of fiberglass over the aluminum then carbon over the fiberglass.
There will be and is a barrier between the sleeve and the carbon stock sheathed in epoxy. I reckon it will be ok but definitely a concerned with wea and tear. Good to hear there is something interesting for you here mate. Keep up the boat building, we need to keep good tradesmen in this world. Rossco
Great episode Rosco!
Thanks Jules
In a dual rudder setup, it might be better to setup the hydraulic cylinder i a way, so that the port side rudder is turning more then starboard rudder when turning the ship to port side, and visa versa.
To illustrate you can draw two circles(one smaller in the center of the other bigger one)
Now imagine the two circles are the paths of your two rudders= the inner path need more rudder angle than the outer path.
Fair dinkum indeed sir.
Thanks Martin it looks great now after many hours of shaping and honing the fair of the stern block. Have a great easter mate. Rossco
I keep seeing videos which talk about carbon and metal corrosion problems
Definately an issue.
Can’t wait to see this tank cross oceans. 🎉
Haha,too funny.
Suggest plain bearings over the roller ones, easily machinable ones. The reduction of friction is only really helpful for having more feedback on the helm instead, but there won't be any feedback with the hydraulic steering. I say that all because I was able to machine more up for myself which worked better than the problematic ones. Where as it would take months to ever be able to get hold of ABSURDLY expensive bearings from Jefa, which weren't available in the state or country.
Don't apologize for using 'scrap' to do it up right. Less waste means less cost and less pollution of our landfills. I'd keep the rudder shelf all one level and add a riser block for the piston anchor point, it would add strength to an area that will see a lot of force and keep even the 'unseen' bits looking as nice as the rest of your craft! At this rate, you'll be having a frothy in your budgie smugglers in just a few months, Beauty!
Thank Mike , I dunno abut budgie smugglers, Janet has banned them in this household. Cheers Ross
You could make a new tiller (protolabs) can give a price as long as you have blueprint They will machine it within a week. They do a lot of one off 😃
Get the rudder stock gland as high as you can
Great job Rosco. Can you out the tiller in line with the rudder and her the piston perpendicular to the rudder? The piston could sit on the tiller support shelf if you extend it aft. Couldn’t tell if there’s enough room or not. Keep up the great work.
You can use a bell crank linkage and basically put your hyd.ram anywhere to meet up with the rudder arm ,i
Hope this helps
Rosco, great video. Have you considered flipping 180° the tiller and maybe rising it higher ? Then you could still run exhaust under and still have tons of room. That would fix the 90° problem I believe. Again just an idea that might work out but you have alot more knowledge about what goes back their.
Try that epoxy expanding foam product in the rudder . Seems like the best stuff for a rudder build
When using an emergency tiller you will need to disconnect the ram because you can’t force oil back through the helm pump from the ram end of the system,cheers
There will be isolating ball valves on each rudder.
Great work Roscoe. The use of the ‘scrap’ foam for the shaft fairing fabrication was eminently sensible.👍
On the rudder project marlarkey - please do use a key on the tiller arm - it is the most effective and enduring solution.
Keep up the excellent work.😀👍⛵️
Make a rudder arm extension, that will give you more room and make it easer to manage the rudder.
like a bell crank style
en.wikipedia.org/wiki/Bellcrank#/media/File:Chambers_1908_Bell_Crank.png
The catamaran is looking really good. So… another week or two and she should be in the water for a test sail. You know when I started watching you start this cat I was thinking you were completely nuts. Don’t worry I still do. LoL but, the two of you making a cat from scratch is so amazing. I can’t wait to see her on her first sail. I am driven… but, you’re on another level. Keep up the great work! Did you pick a name for her yet? 😊
Hilda’s a bulk head long ways and isolate the whole system
Or, let the tube go all the way to the top for even more bracing and let the hydraulic ram sit upside down under the top pointing aft attached to the tiller arm thereby leaving the space much cleaner and roomier?
There has been an outbreak of whales steering off sailboat rudders, build it stronger than it needs to be then make it stronger. I'd have a spare drop hand tiller as well.
Edit: a single bolt will not cope with sheer loads needed, the key spreads the sheer load out.
At 17:01 in the background I love the INXS. One of the greatest bands ever. Nicely done. Any chance you could sneak in some Midnight Oil one of these days?
Hello, great work on your side though I have a concern regarding your hydraulic steering. I'd rather use a sprocket on top of the steering column/shaft and have it engaged with a bar with complementary tto the sprocket teeth. I would then use an elbow joint in the middle of the bar in order to fasten the actuator rod to it. You wuold even be able to install the actuator perpendicular to the hull axis and there would be no stress to the rod by bending it during operation that you had showed you were to install the actuatior in.
Surely you could get either a longer version of the tiller Rosco or I am sure that would not be that expensive to get one cast or machined to your personal preference spec (armchair expert Francios here!)
Edit....Just had a thought...could you put an elbow extension on the arm, that way it won't alter the ratio of movement.
Gidday Frank, I am more inclined to have a shorter tiller as the hydraulic ram has a short stroke and are extremely efficient. Ross
Ross fitting out your rudder and mechanics has to be done when you have all parts that allow you to mock up prior to any glassing. The hydronic steering systems are amazing but you have to have everything level and square or you will burn them out in weeks. The slightest deviation in the shaft being true is amplified through your hydronic steering, it increases the load by a lot.
Thanks Mate, I now have everything here ready to suss it all out. Plenty of other stuff happening so difficult to find time to dedicate to this section, it was all a thinking process that is getting more interesting by the day. Rossco
Love your work. Just a thought - you are working everything to the very end of the tiller arm. Will this give you enough actual rudder movement? It seems to me you might need to move the point of attachment of the ram a bit closer to the rudder shaft to magnify the amount of rudder movement.
I’d be tempted to engineer a new tiller mechanism, but I’m not paying.
The tiller arm needs to be shorter not longer.The hey drive unit is very powerful but has only a relatively short stroke,so closer to the pivot point is the way to go to get full rudder movement.I have set up 2 of these systems and once I realised how strong the ram unit is I was very impressed
Thanks Mate, That is also my thinking. I may be able to install the piston from behind which will further improve the situation, but may make bleeding and balancing a bit harder. Rossco
About the only downside to having it off angle like that that I can think of would be a slight bit more difficult to see if there was damage after a rudder strike, but that would be easy enough to sort with some baseline center and travel marks under the tiller arm. A keyway is going to be much stronger than a hole drilled through the shaft for stearing. You can get keyway stock really easily, and grinding in a notch on the stock shaft can be done with simple tools if you don't have access to a machine shop. Taking the space out for the key way will result in about 100% less strength loss than drilling a pin hole in the middle of the tiller casting and shaft would give you. If it were my boat i'd put in a key.
Could you get a longer tiller.
Cheers! No use offering suggestions because you state in this video that you want to wait for the New Year and we are already 4 months into the New Year!!!! So, when is the initial plunge taking place, June-July 2023?
Hi Ross ! Couldn't you make a longer lever arm or yoke out of stacked composite sheet mat'l that would better integrate ram parallel to hull while also giving better attachment to composite rudders shaft ? The reason for yoke with sheet mat'l is that a series of holes with different arcs could be drilled through as backups/adjustment range options. A split or yoke style arm would keep forces centered and square to avoid flexing and twisting forces in linkage.
Looks like you plan to have rudder extend below keel depth behind prop, is there a sacrificial or breakaway section at bottom of rudder or other protection system in plans ?
why not put the steering piston in the back, extending forwards instead?
That's what I was thinking as well cause putting it behind the pivot point I don't think will add more than a foot or two to the hydraulic lines.
I have considered that too Toby, my concern is access for bleeding and servicing so I will make a journey under the back steps to see if it may be a n option. Cheers Mate . Ross
I guess it may be more about accessing to service, bleed and remove. Stay tuned.
I wonder if you could have used the little arm that out boards use between the motor and steering , it would allow you to place the steering rack on the shelf without hitting the sides of the hull.......🤬👍👍👍
Have you allowed for the rudder on the inside of a turn the travel further than the outboard of the turn rudder ?
Why not put the rod pusching from aft? Ie. turn it 180 deg. Then you free up space. Yes it will be longer hydraulic lines and a bit crowded too service the ram but it out of the way
Can you not install an extension arm to the tiller ( looks like three mount holes are available to attach)?
Can't you install that piston parallel along the hull and fabricate a rod of sorts to reach over to the tiller?
There should be a Vetus arm that is longer otherwise I would recommend machining an arm extension.
Hey Rosco. Great stuff mate! Hey - can you put the piston on the other side of the tiller (inboard of it, and reverse the push/pull) so it is completely out of the ‘storage’ section?
Hey Jase.I will have to look into whether I can service the piston from underneath.It will require bleeding and I think,Need to be upright for the bleeding valves.Thanks for thinking it through with me,time will tell.Ross
Fantastic and so inspiering work as usual Rosco but please do not ad a hydraulic system for your roders and steering system. Make it mechanic. When you get problems with hydraulic system out on the water your really get problems. Go traditional and get easy to fix system. On top of it you loose the feeling for the "sail balance" on top of it with a hydraulic system.
6:06 this is the first time i kinda disagree, and only because of the so many posts on reddit (on the various boating subreddits) with cats being smashed from behind in marinas. Whilst obviously it wouldn't do any serious damage... i think it's best to put a bulkhead there, there's no reason to have that space open (at least in my mind) because you already have the rudder, rudder hydraulics, the shelf... might just as well put the bulkhead.
Just my 2 cents, nothing more.
Stay excellent!!!
Looks good. Will it be Ackerman steering to allow the inner rudder blade to turn tighter than the outside.
I have a twin rudder monohull. The boat turns significantly quicker with Ackerman compared to just having the two blades parallel
I had only heard of this in cars,however,given the Rudder bearings are fixed and are about 50cm in length,there would be no way I could enable a linkage or adjustable toe in.Very interesting concept,I think at the speeds we will be going it would be a negligable benefit,but it is a fascinating idea.Rossco
I came here to ask this, but you've beat me to it! Ackerman is easy with a direct connection between the tillers, like on most small catamarans.... I've spent quite a few minutes wondering how to implement it with individual hydraulic control of each rudder, and it's far from trivial!
@@LifeOnTheHullsi didn't want to post a "have you looked into this?" on a new thread but I've heard from aircraft engineers that carbon touching aluminum is a no no due to corrosive reaction. In aircraft a layer of glass is laid between carbon and aluminum.
@@LifeOnTheHulls with hydraulic steering it can be achieved be angling the tiller arm in relation to the hydraulic piston, ie. not perpendicular at straight ahead. The effect is that you get more turning angle one way than the other. You probably can solve your storage room issue at the same time
Hi Ross, would it be feasible to bolt an extension to the aluminium tiller arm then you can have the piston against the wall of the hull?
Regards Stephen
I thought of that too, but then thought the piston arm would need to travel further to get the 35 degrees in each direction required. Good thought. Great work Ross.
Can you not extend that rudder arm? A steel flat bar with two drilled holes and some bolts would do it. It would be a neat job also.
Could you make a longer tiller arm so the ram is parallel to the hull side
That is an option however I will look to a shorter tiller as the stroke of the piston is short and extremely efficient. I have a few options to consider here including reversing the ram from behind which may open up the space for more storage. Rossco
Why not extend the Aluminium tiller bracket so the piston can sit parallel to the in board wall on the shelf?
what paint and spray set up are you going to use me old cocker
No paint buddy.Biat will be finished in gel coat ,then flow coat as the final coat,wet sanded then polished.Rossco
I've watched a few boat video's where water has gotten into the foam core and it's been a right pain to repair. When it is just an empty fibreglass shell you can drill a hole and drain out the water. What are the benefits of being solid foam core?
The weight of solid glass make it almost prohibitive in a cat of this size. Foam is used to add rigidity without weight. In fact a 10mm core of foam will add 7 times the rigidity of the substrate with the same laminates bridging the core. 20mm will add up to 37 times the stiffness and with less weight. Foam laminated correctly will be protected from moisture however, there are many things that need to be actioned to avoid water ingress. Coring every hole with solid resin and cabosil filler or epoxy with cabosil will eliminate water ingress in windows , hatches, fitting etc. Water is more common in plywood and balsa wood which is what the majority of cats were built with prior to 2005. Cheers Ross
Do they make a rotary actuator instead of the piston? Like the helm pump?
Not that I know of.
@@LifeOnTheHulls a quick google shows them at ship scale, and hydraulic motors are common. Could be a good option to eliminate the aluminium arm, and through rod piston. But guessing you might be ahead of the videos too 😂
Shame you can’t get an extension for the tiller arm… 🤔
Why don't you put aluminum extension Square tube on that
Sure you have a good reason but why can't the tiller point directly aft and the piston bolt to the underside of the deck- step ?
That maybe a solution.I will wait till the bearings arrive ,but,I like that plan, the less shelves and crap in there the better.
@@LifeOnTheHulls Also have to link the rudders for the emergency tiller to work proper mate
Why not put the steering ram on a shelf aft of the rudder tube (rather than forward, where you are mocking it up)) - and leave the area you were sitting in the video as clear as possible? I realise the videos are uploaded months after being recorded - so the boats probably in the water by now 🙂 but I thought I'd comment to appease the mighty algorithm anyway. Stay safe out there.
This boat is going to be like a giant white cockroach, able to survive a nuclear war and basically unkillable.
Haha,
just extend the tiller
Didn't you say that you were 'spraying' in this episode?
Sorry mate that was where I was up to this week in teal time.Vids are 3 months behind.Alwsys try to give a real life peak.My bad.Rossco
Great job mate maybe ugly as hat full of backsides now but you will get it right
That is brilliant , I love that comment.
So confused as to why you didn’t just fabricate a rudder arm extension?
As mentioned I am using commercially available equipment in critical areas to ensure availability of parts in remote locales.This tiller is spot on for purpose and time to fabricate yet another piece is hard to allocate with such an immense job ahead.Cheers Ross
What??.... No swearing? How will we get true representation of the nature of the beast? 😂 The thing will be under water anyway. 😁