I was in the US Navy and served aboard destroyers, and went to almost 40 countries on 5 continents and thru 4 oceans. Never gave any thought to the rudders, beyond the simple fact they steer boats and ships. Retirement gives one an opportunity to slow down, learn about and reflect on many things we simply didn't have time for in our working year's. I enjoyed this video. Thank you!
I'm a tugboat Captain, working in Houston, and the ship channel leading from the Gulf. I show your video to steersman trainees, as it shows the physics very well. You should make a second video on 'flanking rudders' that tugs use to make radical turns, with long tows.
I'd guess ships aren't that common of an interest. I feel like most people wouldn't expect them to be interesting and would never really give them much thought.
I’ve been interested in things nautical for over 50 years. You do a GREAT job teaching the subject. Ship handling in heavy weather and the use of sea anchors would make an excellent topic, if you haven’t done one already.
The speed of the air over the wing is not the reason for the lift generated, but it is a common misconception. It is actually the same principle as you explained with the rudder: the wing is slightly angled and redirects airflow. This causes a pressure difference which generates lift. The speed difference is just a result of the pressure difference
I get so irritated whenever people use the 'speed' explanation as it is so inaccurate. I'm glad someone else knows about it! I wish this comment was higher up, or if Casual Navigation didn't make the mistake in the first place!
The Angle of Attack is an extremely important concept in aerodynamics. It's basically "how much angled the wing is in relation to the incoming airflow and so how big the chunk of redirected air is". Without this angle a wing will not work.
Both answer are good and are in fact needed. If you use only displaced air to get your lift, then how do you explain stall? Stall is the lost of the low pressure pocket of air above the wing, which is easier to explain with Bernoulli. The balance between the 2 depend on the shape of the wing, fighter goes too fast to really need Bernoulli, they would generate too much lift, so their wings are mostly symmetrical. If you look at a glider it's the opposite. At the end you can use both, if I was building a plane with a known wing, I won't need Bernoulli, but if I was building a wing, I would use it.
@@jehoiakimelidoronila5450 since the rudder was on the right side, a ship could dock at a port on its left (or port) side. I am not that well versed in nautical terminology and history though, so if anyone knows their stuff better, please feel free to correct me
@@jehoiakimelidoronila5450 also, in German the starboard side is still called Steuerbord, and port side is Backbord, because most people the dominant hand is the right hand so the left is called Backhand, hence Backbord
@@mariebcfhs9491 the port side of a ship in English used to be called "larboard." it was changed in like the 16th century or so to reduce confusion for obvious reasons.
I learned about rudder types that I hadn’t heard of before, so that was good, it might have been good to point out that more turning authority can be had also by just making the rudder bigger. So the fancy rudder types are done to minimize depth, drag and length for a given amount of rudder authority. And you can minimize depth and length, and get some redundancy, by having multiple rudders. It’s all trade offs.
It would have been more helpful to point out which specific concepts have been misrepresented here, as opposed to just giving an unhelpful and quite frankly lazy critique.
Thank you for your video . You have answered a question that has puzzled me for years . I saw a drawing of the system. Used to keep passenger liners stable in rough conditions. Where they would have short , " wings " on the sides underwater , that turned to keep it more upright . This design had short wedge shape on the trailing edge . I have asked many people why this was . Now thanks to your explanation of a Schilling rudder , I know !
I'm glad he mentioned stalling, this was a big thing we learned racing 420s vs the 420E sailboats. The E's had smaller riders on the same style of boat and overaggressive skippers could stall the rudders easily if they were used to the other style.
I race sailboats. On a friends boat, he had a NACA 0012 foil, but his photocopy of the leading edge came to a point, so he made it that way. It stalled so easily, it was difficult to get around the course. My own rudder is proper NACA 0012, with a circular leading edge, as it should be. I chose a non- elipically loaded planform, so that when the rudder starts to stall, it warns me, so I can correct it before I lose control of the boat. Also, appraoching stall at speed on my 19 ft boat can load up the hinge to around a 2000 lb load. I've had to replace bent 3/16" thick welded stainless steel hinges (gudgeons). You do know that sails work as foils, so that the generated low pressure allows us to go into the wind?
The Bernoulli effect not only effects our wings, rudder, and elevators in the air but also effects other things in a fluid environment. I was shocked to learn helicopters could stall to but when I thought about for a bit it made sense. This has also made how submarines glide underwater more interesting since those wings on the sides actually serve a purpose. Submarines can be controlled like aircraft underwater and can stall, but of course the ballast tanks cause it to behave like an airship.
In smaller boats that have an unbalanced rudder (so the center of friction is away from the rotation axis) a stall is not an issue, because the boat will still turn because of the friction, although it will lose more momentum.
Same as any control surface on an airplane can stall as well. They are usually designed to make that impossible as long as the aircraft remains within its design envelope, but either by external factors (icing for example) or flying outside the envelope (transonic speeds) can lead to stalled surfaces. Usually not an issue on the rudder, but it can happen to ailerons and the elevator, recovery from that issue can be very counterintuitive.
@@drewthompson7457 A concept I have to teach newbies on my boat. Don't stall the keel or rudder. Funny about your friend's photocopy. I should make a template and check the profile of my rudder ad keel. Rudder looks like NACA 0012 but might not be. Keel is not but is a compromise like most things.
I dont want to be a party pooper, but (2:30) the difference in speed was a theory that has been disproven. So what we are left with is Newton's third law, Bernoulli's principle and Magnus effect. (For symmetrical airfoils)
Robin Marquardt what makes you think that there is no speed differential across an airfoil? Every advanced textbook on fluid mechanics I have studied in both undergraduate and graduate school has dealt extensively with airfoils and there is speed differential. Granted the mechanics of an airfoil are extremely complicated (entire PhD dissertations have been written on the subject) so there is no way it can be described in a few sentences, but the basics can be understood by reading a good textbook in introductory physics if you want more information.
@@GregKittle aor does not flow faster or slower across an airfoil because there is a longer way. If corrected for Bernoulli's principle, there is no difference. I actually did experiments and in addition real life applications suggest otherwise. I spend 120.000$+ on this stuff btw. The fact is that what is taught is not what's actually true. Those are theories. As of now there are 3 accepted theories on how lift is actually created.
@Agamemnon1002 the air above the wing is not faster because it has a longer way to the trailing edge than the bottom. It is a common misconception. For one air wouldn't have to or want to end up at the same time at the end of the wing(top and bottom) and in experiments it's seen that it doesn't.
Would love it if you expanded on the rudder stall. How does that manifest to the operator and what consequences are there? What should you do if you need to urgently turn in an emergency but you've passed the stall point?
Thank you ,,,,, this is all great for my Orals on Thursday 5th March 2020,,,, all the Colregs stuff is so much easier than reading them. Im Very grateful to you
Great video! The fishtail makes me think of the winglets on aircraft wings. Their purpose is also to minimize the air flowing around the edge from high to low pressure. The ship version seems to include additional effects, such as deflection, which you don’t have with planes. But they are amazingly effective, increasing efficiency by several percent. That’s why they are ubiquitous today.
What about repositioning the fulcrum of the rudder? Instead of making a rudder a hinge, allow some leading edge of the rudder to be forward of where the rudder pivots. Wouldn’t that allow for a more responsive rudder?
What about trim tabs on large rudders? Large rudders are too difficult to move, so the trim tab moves the opposite direction to move the rudder in the direction you want it to move with a much smaller force.
Thank you for sharing. Hope you can do a video on the shape of the rudder. I think there are a variety of shapes. Some straight, tapered or curvy, with larger area at the bottom as compared to the top. Thanks again.
The way a wing stalls is slightly different in that the airflow separates from the airfoil due to turbulence, you never really get out of the flow regardless of angel of attack due to forward movement.
3:03 Idea: Split tail rudder The tip can split into two when turning and fold back into one when not That way there would be less drag at straight lines
Nice video - Q: has there ever been investigations of putting a rudder towards the front of the ship? I ask because of the turning force created by the rudder is ahead of the center of mass of the ship, would that allow the ship to turn a tighter circle? Or the "forward" rudder could help a ship turn tighter even if it also had a traditional stern rudder. Again, great channel.
f12mnb A rudder at the forward end is not a new concept. There are a handful of ships with them already, but these generally only have a bow rudder when the ship is designed to be run astern for a prolonged period of time such as some icebreakers and ferries. A rudder at the bow for a ship moving ahead would not be able to steer. This is due to the vessels pivot point. A pivot point is quite difficult to explain here because of the complicated hydrodynamics involved. But, in simple terms a pivot point is a point about which a vessel turns. When a vessel is moving ahead, the pivot point is near the bow....so when a rudder angle is applied the vessel turns easily because the force of the thrust acting on the rudder has a long lever to push on and will be very effective. Imagine trying to undo a very tight bolt with a spanner.....if you use a short spanner you only have a short lever and will use a lot of effort to undo the bolt. If you use a longer spanner, you don’t need to use as much power as the lever is longer. The bolt in this case is the pivot point and the other end of the spanner is the rudder. The shorter the distance between the rudder and the pivot point means the ship is harder to turn, the further away from each other they are, the easier it is to turn. Chris - Marine Pilot
@@marinepilotchris3048 Thanks for the reply. I've been thinking over your answer and analogy and quite like the spanner/wrench analogy. Which makes me wonder, if instead of just a rear (standard) rudder, a vessel has two sets - a main rear one and an auxillary one in the front. I'm thinking of the land analogy of very long vehicles that have a front and rear steerable wheels (older long ladder fire trucks had this arrangement). Since you are trying to pivot around what sounds like the center of mass of the ship, this is like have a large two armed tool - like some drill taps or tire irons where there are two arms from a center pivot point. It would add to the complexity of the ship but might make it easier to turn or dock some vessels.
f12mnb in order to achieve the manoeuvrability of vessels about the centre of mass bow thrusters are used. A bow thruster takes many forms and designs, but by far the most common is the tunnel thruster where a prop is placed in a tunnel athwartships through the bow of a ship. When the prop turns it sucks water from one side of the tunnel and ejects it from the other side. This will provide a turning force much greater than any bow rudder could produce. Don’t forget that a rudder needs water flow over it to have any effect. This would mean that if the ship was stationary and wanting to swing about the centre of mass, then you’d also need a bow propeller to provide that flow. The expense of installing a bow rudder would not be cost effective when a simple bow thruster does the job much more effectively and doesn’t require the ship to be moving ahead/astern to give its full turning power.
Best video.. Until now.. Why dont you make a video on all parts all the type of rudders you explained in this video.. It will be a unique video never done by anyone and will immensely help students-fir-life like us..
You included a picture of a Miele canister vacuum cleaner at 4:45, when talking about Hoover’s, I guess aptly making the point that at least in the UK “Hoover”, “hoovering”, etc. is in fact a generic term (that is definitely not the case in the US).
Being a pilot whenever I look at an airfoil design I think about drag. How come that in ship design it appears to rarely be considered (e.g. the fishtail looks like an awful induced drag generator). Is it because the cost of fuel in ship design is less relevant or simply because it is negligible when compared to total drag?
I think it is probably negligible compared to the ship itself. I guess drag is only really a consideration when the rudder is straight anyway. As soon as it turns, the drag helps with the turn. Would be interesting to see the different fuel consumption with different rudders though
@@CasualNavigation Probably also has less of an effect for the ship as the rudder is tiny in comparison to the hull of the ship and being centre mounted doesn't really add to the hulls cross section in the water and of course it's contained within the slipsteam of the ship. Aircraft on the other hand have a minimum of two giant aerofoils sticking off the side of the aircraft, most of course also have two smaller upside down aerofoils (horizontal stabiliser) and the vertical stabiliser at the rear too none of these really get any slipstream benefit from the main fuselage so that probably adds to the much greater significance on the total drag. Plus the aerofoil design of the wings means they constantly produce induced drag as a side effect of developing lift too so anything that can be done to optimise this to a minimum especially for a craft that operates at such high speeds has massive effects on efficiency, thus such as the use of winglets to reduce the amount of vortex shedding which significantly increases induced drag.
Are there any segmented fishtail rudders? I mean the dual segments works just like a multi-level wing on a race car and the fishtail acts like an aero break but functions like and end plate. so it seems that you could be able to get a much higher amount of maneuverability from some combination of the two. So long as the fishtail is only on the rear most segment of the rudder because otherwise it would negate some of the benefits of that style of rudder
FOOL ! Airfoils operate in air , think about it , there is a clue in the name . Backwards is a single word . The man was correct and unlike you did not make a fool out of himself .
Now with the shilling rudder, doesn’t it take a drag hit given it’s dragging the wider tail through the water, instead of the other types that are all narrow tipped?
Not the best description of how airfoils work. There's no reason that the top and bottom air have to meet up again, and extreme designs that would take advantage of that rule prove useless.
I've been experimenting with a durable adaptive or morphing rudder. Much is published for aeronautical applications, but I've found it difficult to find papers for surface craft, just light-weight, robotic fish-like drones. Attempts to open the topic in various forums spark scorn from beneath a mask of civility, at best. Can you point me towards any research published on this concept?
What about high speeds, I would think that something like the fishtail version would probably increase drag, is that something that's relevant enough to prefer different shapes for high speeds and also would increased strain on the rudder influence what type to use? Or is it in practice so much more important to have good performance at low speeds that performance at high speeds isn't really a concern anyway?
2nd rudder type is merely a symmetrical shape. It does not act like. Clark Y airfoil shape. It acts only as a symmetrical wing would on an aircraft, making lift solely when there is a positive Angle Of Attack. Its advantage is that is slides through the water better with the curve and taper, like fairings for wing struts or wheel pants. Great information on the 3rd and 4th type rudders.
Any chance you could do a video on why rudders are placed where they are. Seems like a mid, or forward rudder would give a much different feel. For sailing, Why not have the rudder attached to the keel? Edit: guess they have figured this out a long time ago with the full keel hull
Think you are talking about bow thrusters. They only work in really slow speeds, and usually need some time to get ready to be used. Deckhands need to open vents, the hydraulic system needs to build pressure, the engineers have to start enough generators so the ship has a high enough electrical supply, these things are high powered macinery using up a LOT of electricity, then the bridge needs to test and document them before use. While manouvering slowly, the bow thruster is very useful. On single propeller ships, the aft pulls to one side (always the same side) when the engine is driven astern. Pair that with a bow truster and you can turn on a dime or even go somewhat sideways. If you have two propellers and a bow thruster, you can manouver the ship in any dorection you can possibly think of by combining different levels and directions of thrust on each.
It will reduce the effectiveness of the rudder. The rudder will generate less turning force. The rate of turn will be slower and the turning circle will be larger. If the rudder stalls, you are better reducing the angle slightly, then you will generate more force.
TY for a great informative video. I vvanted to ask though, vv/the last 2 rudders, you said that they help @ lovv speeds , but vvouldnt they allovv even greater turning @ higher speeds ? Sorry for the stupid question & TY again for the video as I've subscribed.
If a boat is floating without any means of propulsion -- that is, its speed is determined only by the speed of the current -- can a rudder change the direction of the boat? If you recall in the movie _The African Queen__ Bogart explained to Katherine Hepburn that it would do no good for her to operate the rudder. They were drifting downstream with the current and the rudder was not able to provide any steering unless the boat was moving faster than the current. Is that true?
Seems that way. I tried looking it up and the answer involves complicated fluid dynamics and way more information on rudders than I ever care to wade through.
I have not covered acts and publications yet, as I don't find them as interesting as navigation itself. That's why navigation is the main focus of this channel.
Bull. The airfoiled rudder works on the exact same principles as the squared off rudder. It just does so more efficiently because it has less drag. The velocity differential is still there for either shape.
I was in the US Navy and served aboard destroyers, and went to almost 40 countries on 5 continents and thru 4 oceans. Never gave any thought to the rudders, beyond the simple fact they steer boats and ships. Retirement gives one an opportunity to slow down, learn about and reflect on many things we simply didn't have time for in our working year's. I enjoyed this video. Thank you!
Nah man this video is lying to you it’s actually a group of guys under water pushing it around
@@chrisrobles824 fax
@@chrisrobles824 strenght:100
What was your rank Sir
Which rate? If ESWS qual’d, you would have certainly had to spend time down in aft steering learning the basics!
I'm a tugboat Captain, working in Houston, and the ship channel leading from the Gulf. I show your video to steersman trainees, as it shows the physics very well. You should make a second video on 'flanking rudders' that tugs use to make radical turns, with long tows.
Holy shit no
@@user-lr6ce1mw4k yes
M now coming to Houston from.mexico
I second the flanking rudder video idea
Never been into ships, never found them interesting.....but your videos are marvelous....
i kinda feel the same way. shows again how anything can be appealing and interesting, if it's communicated properly. maybe teacher could take note.
Same here. One of these videos just kind of appeared in my Recommended out of nowhere and I watched and now I'm hooked.
@@borntochill bro I hate teachers, even an interesting thing becomes boring😵😵😵
Odlicni su mu uploadovi!
Heretic!
I don't understand how this channel has so few subs, the videos are interesting and such high quality. Keep up the good work buddy!
I'd guess ships aren't that common of an interest. I feel like most people wouldn't expect them to be interesting and would never really give them much thought.
It's quality stuff. Good, useful information. No glitz, no shouting idiot, no irrelevant shots. Excellent. Thank you.
236K is alot dude
Daniel Kaitel reading are so boring
Because not everyone is into ships? were you really not able to think of that?
I’ve been interested in things nautical for over 50 years. You do a GREAT job teaching the subject. Ship handling in heavy weather and the use of sea anchors would make an excellent topic, if you haven’t done one already.
I am an engineer working in IT, and discovering this channel suddenly made me want to change my life completely and start working on boats 😂😂
I've been repairing boats for years ... am now a marine surveyor... and I had no idea that rudders worked this way. This was a great video!
Wow... simple and logical explanations, I need a professor like you...
Thanks Matinalii
The speed of the air over the wing is not the reason for the lift generated, but it is a common misconception.
It is actually the same principle as you explained with the rudder: the wing is slightly angled and redirects airflow. This causes a pressure difference which generates lift.
The speed difference is just a result of the pressure difference
I get so irritated whenever people use the 'speed' explanation as it is so inaccurate. I'm glad someone else knows about it! I wish this comment was higher up, or if Casual Navigation didn't make the mistake in the first place!
The Angle of Attack is an extremely important concept in aerodynamics.
It's basically "how much angled the wing is in relation to the incoming airflow and so how big the chunk of redirected air is".
Without this angle a wing will not work.
@@kramrle Dead link.
@@TimothyChapman
Thx for the hint. Link is updated.
docshare01.docshare.tips/files/3422/34223648.pdf
Both answer are good and are in fact needed. If you use only displaced air to get your lift, then how do you explain stall? Stall is the lost of the low pressure pocket of air above the wing, which is easier to explain with Bernoulli.
The balance between the 2 depend on the shape of the wing, fighter goes too fast to really need Bernoulli, they would generate too much lift, so their wings are mostly symmetrical. If you look at a glider it's the opposite.
At the end you can use both, if I was building a plane with a known wing, I won't need Bernoulli, but if I was building a wing, I would use it.
fun fact
Steering board in German is Steuerbord, it is mounted on the right, which is why Starboard is the right hand side of a ship
Thanks for further insight! Now that I think about it, what about the "portside" though...
@@jehoiakimelidoronila5450 since the rudder was on the right side, a ship could dock at a port on its left (or port) side.
I am not that well versed in nautical terminology and history though, so if anyone knows their stuff better, please feel free to correct me
@@jehoiakimelidoronila5450 almost all ports required large ships to dock on their left side so the left side is called port sode
@@jehoiakimelidoronila5450 also, in German the starboard side is still called Steuerbord, and port side is Backbord, because most people the dominant hand is the right hand so the left is called Backhand, hence Backbord
@@mariebcfhs9491 the port side of a ship in English used to be called "larboard." it was changed in like the 16th century or so to reduce confusion for obvious reasons.
I learned about rudder types that I hadn’t heard of before, so that was good, it might have been good to point out that more turning authority can be had also by just making the rudder bigger. So the fancy rudder types are done to minimize depth, drag and length for a given amount of rudder authority. And you can minimize depth and length, and get some redundancy, by having multiple rudders. It’s all trade offs.
Most of your videos are great, the physics is usually correct and well explained. This one was airfoil misconceptions greatest hits.
Right? I didn't quite expect that.
It would have been more helpful to point out which specific concepts have been misrepresented here, as opposed to just giving an unhelpful and quite frankly lazy critique.
I love that your videos are informative and short without all the bloatware. Keep it up!
Thank you for your video . You have answered a question that has puzzled me for years . I saw a drawing of the system. Used to keep passenger liners stable in rough conditions. Where they would have short , " wings " on the sides underwater , that turned to keep it more upright . This design had short wedge shape on the trailing edge . I have asked many people why this was . Now thanks to your explanation of a Schilling rudder , I know !
I'm glad he mentioned stalling, this was a big thing we learned racing 420s vs the 420E sailboats. The E's had smaller riders on the same style of boat and overaggressive skippers could stall the rudders easily if they were used to the other style.
I'm a pilot and I didn't know that ship rudders could stall
I race sailboats. On a friends boat, he had a NACA 0012 foil, but his photocopy of the leading edge came to a point, so he made it that way. It stalled so easily, it was difficult to get around the course. My own rudder is proper NACA 0012, with a circular leading edge, as it should be. I chose a non- elipically loaded planform, so that when the rudder starts to stall, it warns me, so I can correct it before I lose control of the boat. Also, appraoching stall at speed on my 19 ft boat can load up the hinge to around a 2000 lb load. I've had to replace bent 3/16" thick welded stainless steel hinges (gudgeons). You do know that sails work as foils, so that the generated low pressure allows us to go into the wind?
The Bernoulli effect not only effects our wings, rudder, and elevators in the air but also effects other things in a fluid environment. I was shocked to learn helicopters could stall to but when I thought about for a bit it made sense.
This has also made how submarines glide underwater more interesting since those wings on the sides actually serve a purpose. Submarines can be controlled like aircraft underwater and can stall, but of course the ballast tanks cause it to behave like an airship.
In smaller boats that have an unbalanced rudder (so the center of friction is away from the rotation axis) a stall is not an issue, because the boat will still turn because of the friction, although it will lose more momentum.
Same as any control surface on an airplane can stall as well. They are usually designed to make that impossible as long as the aircraft remains within its design envelope, but either by external factors (icing for example) or flying outside the envelope (transonic speeds) can lead to stalled surfaces. Usually not an issue on the rudder, but it can happen to ailerons and the elevator, recovery from that issue can be very counterintuitive.
@@drewthompson7457 A concept I have to teach newbies on my boat. Don't stall the keel or rudder. Funny about your friend's photocopy. I should make a template and check the profile of my rudder ad keel. Rudder looks like NACA 0012 but might not be. Keel is not but is a compromise like most things.
I never knew there were different rudders as shown. I’m a better person for this video. Thanks.
Thank you so much! Today I have learned again. YT is the best school.
Wow! Great job you do, guys! Just thinking of the time you invest to create this wonderful material. Thumbs up!
Had no idea that rudders could stall. Makes perfect sense now that you've made me think about it.
I dont want to be a party pooper, but (2:30) the difference in speed was a theory that has been disproven.
So what we are left with is Newton's third law, Bernoulli's principle and Magnus effect. (For symmetrical airfoils)
Robin Marquardt what makes you think that there is no speed differential across an airfoil? Every advanced textbook on fluid mechanics I have studied in both undergraduate and graduate school has dealt extensively with airfoils and there is speed differential. Granted the mechanics of an airfoil are extremely complicated (entire PhD dissertations have been written on the subject) so there is no way it can be described in a few sentences, but the basics can be understood by reading a good textbook in introductory physics if you want more information.
@@GregKittle aor does not flow faster or slower across an airfoil because there is a longer way. If corrected for Bernoulli's principle, there is no difference. I actually did experiments and in addition real life applications suggest otherwise. I spend 120.000$+ on this stuff btw. The fact is that what is taught is not what's actually true. Those are theories. As of now there are 3 accepted theories on how lift is actually created.
@@GregKittle air above an airfoil has no intention to end up next to the molecule it parted ways with before hotting the leading edge.
@Agamemnon1002 yes
@Agamemnon1002 the air above the wing is not faster because it has a longer way to the trailing edge than the bottom. It is a common misconception. For one air wouldn't have to or want to end up at the same time at the end of the wing(top and bottom) and in experiments it's seen that it doesn't.
The video has explained the fundamentals of ship propulsion in excellent way. How a thrust force plays role in reducing drag in ships.
Would love it if you expanded on the rudder stall. How does that manifest to the operator and what consequences are there? What should you do if you need to urgently turn in an emergency but you've passed the stall point?
When I'm asked how does a rudder work, i always say "just fine"
Thank you ,,,,, this is all great for my Orals on Thursday 5th March 2020,,,, all the Colregs stuff is so much easier than reading them. Im Very grateful to you
Great video! The fishtail makes me think of the winglets on aircraft wings. Their purpose is also to minimize the air flowing around the edge from high to low pressure. The ship version seems to include additional effects, such as deflection, which you don’t have with planes. But they are amazingly effective, increasing efficiency by several percent. That’s why they are ubiquitous today.
Since i have a rc model ship that shouldn't go too fast, thIs have been more informative than expected.
I remember when i was in kindergarten I draw ships with propeller and rudder, and those teachers clearly didn’t like the idea of that
Great class! 👏👏👏
Your channel made me get into ships
Love your explanation and your contents 👌💯
Thanks Shayan. Glad you liked it!
What about repositioning the fulcrum of the rudder? Instead of making a rudder a hinge, allow some leading edge of the rudder to be forward of where the rudder pivots. Wouldn’t that allow for a more responsive rudder?
I already know about it, I just wanted to see how much complex the explanation can get
What about trim tabs on large rudders? Large rudders are too difficult to move, so the trim tab moves the opposite direction to move the rudder in the direction you want it to move with a much smaller force.
so the rudder is so big, it has its own rudder?
Thank you for sharing. Hope you can do a video on the shape of the rudder. I think there are a variety of shapes. Some straight, tapered or curvy, with larger area at the bottom as compared to the top. Thanks again.
WONDERFUL information...
Merry Christmas
I’m struggling to get my head around the minds of the 259 people (at the time of my viewing) who gave this simple and informative video a thumbs down.
I would agree except YT hid the counter for some BS reason.
The way a wing stalls is slightly different in that the airflow separates from the airfoil due to turbulence, you never really get out of the flow regardless of angel of attack due to forward movement.
You should do a video on how boats and ships navigate and not ground in unfamiliar ports and harbours (like private vessels also)
Yes please!
All of your videos are so good. But only thing difficulty found is don't have subtitle. So kind request you to arrange subtitleS
Love your channel
3:03 Idea: Split tail rudder
The tip can split into two when turning and fold back into one when not
That way there would be less drag at straight lines
Love from BANGLADESH 🇧🇩
Nice video - Q: has there ever been investigations of putting a rudder towards the front of the ship? I ask because of the turning force created by the rudder is ahead of the center of mass of the ship, would that allow the ship to turn a tighter circle? Or the "forward" rudder could help a ship turn tighter even if it also had a traditional stern rudder.
Again, great channel.
f12mnb A rudder at the forward end is not a new concept. There are a handful of ships with them already, but these generally only have a bow rudder when the ship is designed to be run astern for a prolonged period of time such as some icebreakers and ferries.
A rudder at the bow for a ship moving ahead would not be able to steer. This is due to the vessels pivot point. A pivot point is quite difficult to explain here because of the complicated hydrodynamics involved. But, in simple terms a pivot point is a point about which a vessel turns. When a vessel is moving ahead, the pivot point is near the bow....so when a rudder angle is applied the vessel turns easily because the force of the thrust acting on the rudder has a long lever to push on and will be very effective.
Imagine trying to undo a very tight bolt with a spanner.....if you use a short spanner you only have a short lever and will use a lot of effort to undo the bolt. If you use a longer spanner, you don’t need to use as much power as the lever is longer. The bolt in this case is the pivot point and the other end of the spanner is the rudder. The shorter the distance between the rudder and the pivot point means the ship is harder to turn, the further away from each other they are, the easier it is to turn.
Chris - Marine Pilot
@@marinepilotchris3048 Thanks - like the analogy.
@@marinepilotchris3048 Thanks for the reply. I've been thinking over your answer and analogy and quite like the spanner/wrench analogy. Which makes me wonder, if instead of just a rear (standard) rudder, a vessel has two sets - a main rear one and an auxillary one in the front. I'm thinking of the land analogy of very long vehicles that have a front and rear steerable wheels (older long ladder fire trucks had this arrangement). Since you are trying to pivot around what sounds like the center of mass of the ship, this is like have a large two armed tool - like some drill taps or tire irons where there are two arms from a center pivot point.
It would add to the complexity of the ship but might make it easier to turn or dock some vessels.
f12mnb in order to achieve the manoeuvrability of vessels about the centre of mass bow thrusters are used. A bow thruster takes many forms and designs, but by far the most common is the tunnel thruster where a prop is placed in a tunnel athwartships through the bow of a ship. When the prop turns it sucks water from one side of the tunnel and ejects it from the other side. This will provide a turning force much greater than any bow rudder could produce. Don’t forget that a rudder needs water flow over it to have any effect. This would mean that if the ship was stationary and wanting to swing about the centre of mass, then you’d also need a bow propeller to provide that flow.
The expense of installing a bow rudder would not be cost effective when a simple bow thruster does the job much more effectively and doesn’t require the ship to be moving ahead/astern to give its full turning power.
@@marinepilotchris3048 Thanks - that makes sense. Forgot about thrusters. Much easier to control and no need to have flowing water over the surfaces.
I feel like it's fairly self evident but it's a well made video so I guess I'm not complaining.
Best video.. Until now.. Why dont you make a video on all parts all the type of rudders you explained in this video.. It will be a unique video never done by anyone and will immensely help students-fir-life like us..
Thanks Anup. Those are good ideas for future topics
You should do a video on ship corrosion and rust control measures.
always known how they work but i love how he individualizes every factor gained by different designs over the evolution of humanity's sea legs
I'm starting to like ships because of you
thank you for the knowledge
Great video as always 👍🏼 👌, truly useful
What would happen if you had a combination of the fishtail and Becker rudder?
I don't know how I got here but I considered myself lucky.
P.S I never shown an interest in ship design but UA-cam recommends me here :)
Thanks Talking Human. Glad you found it interesting.
The Casual Navigator I thank you that it is interesting.
Lmao bet I’m the only one who heard the washing machine in the background. 1:25
Nice explanation
I LOVE THIS CHANNEL!!!
You included a picture of a Miele canister vacuum cleaner at 4:45, when talking about Hoover’s, I guess aptly making the point that at least in the UK “Hoover”, “hoovering”, etc. is in fact a generic term (that is definitely not the case in the US).
I read that the generic term was damned by President Hoover.
Being a pilot whenever I look at an airfoil design I think about drag. How come that in ship design it appears to rarely be considered (e.g. the fishtail looks like an awful induced drag generator). Is it because the cost of fuel in ship design is less relevant or simply because it is negligible when compared to total drag?
I think it is probably negligible compared to the ship itself. I guess drag is only really a consideration when the rudder is straight anyway. As soon as it turns, the drag helps with the turn. Would be interesting to see the different fuel consumption with different rudders though
@@CasualNavigation Probably also has less of an effect for the ship as the rudder is tiny in comparison to the hull of the ship and being centre mounted doesn't really add to the hulls cross section in the water and of course it's contained within the slipsteam of the ship. Aircraft on the other hand have a minimum of two giant aerofoils sticking off the side of the aircraft, most of course also have two smaller upside down aerofoils (horizontal stabiliser) and the vertical stabiliser at the rear too none of these really get any slipstream benefit from the main fuselage so that probably adds to the much greater significance on the total drag. Plus the aerofoil design of the wings means they constantly produce induced drag as a side effect of developing lift too so anything that can be done to optimise this to a minimum especially for a craft that operates at such high speeds has massive effects on efficiency, thus such as the use of winglets to reduce the amount of vortex shedding which significantly increases induced drag.
(rudder x fuselage)
Good little video.
Are there any segmented fishtail rudders? I mean the dual segments works just like a multi-level wing on a race car and the fishtail acts like an aero break but functions like and end plate. so it seems that you could be able to get a much higher amount of maneuverability from some combination of the two. So long as the fishtail is only on the rear most segment of the rudder because otherwise it would negate some of the benefits of that style of rudder
You have gotten how airfoils work back wards
Faster=lower pressure
Slower= higher pressure
Yeah, it's a bit off
what part of the video are you talking about? This part 2:45?
He's correct - he wrote slower water flow is higher pressure, which is true from Bernoulli's equation?
Ya, lp=high speed, hp=low speed fr airfoil to create lift
FOOL ! Airfoils operate in air , think about it , there is a clue in the name . Backwards is a single word . The man was correct and unlike you did not make a fool out of himself .
Now with the shilling rudder, doesn’t it take a drag hit given it’s dragging the wider tail through the water, instead of the other types that are all narrow tipped?
Not the best description of how airfoils work. There's no reason that the top and bottom air have to meet up again, and extreme designs that would take advantage of that rule prove useless.
The reason extreme designs fail is due to flow detachment, not because the principle is flawed
To be fair it is a rather common and easy to visualize explanation and I think for the purpose of this video it's more than sufficient.
I've been experimenting with a durable adaptive or morphing rudder. Much is published for aeronautical applications, but I've found it difficult to find papers for surface craft, just light-weight, robotic fish-like drones. Attempts to open the topic in various forums spark scorn from beneath a mask of civility, at best. Can you point me towards any research published on this concept?
I have some additional rudder questions for you. Why isn’t the rudder longer wider? Why not two rudders?
@Opecuted thank you - I appreciate your taking time to answer and you have awesome videos!
@Opecuted ohh ha on me :) thank you and have a great day!
For high speed does the rudder shape or additions have a big impact as in slow speed? What happens if a ship steers too fast?
Maybe tips or the hull buckles?
The rudder may break due to the force
Please describe the "Williamson turn" or any MOB procedures
What about high speeds, I would think that something like the fishtail version would probably increase drag, is that something that's relevant enough to prefer different shapes for high speeds and also would increased strain on the rudder influence what type to use?
Or is it in practice so much more important to have good performance at low speeds that performance at high speeds isn't really a concern anyway?
I would guess some ships like tugboats or small ferries would need more maneuverability than high speed efficiency
2nd rudder type is merely a symmetrical shape. It does not act like. Clark Y airfoil shape. It acts only as a symmetrical wing would on an aircraft, making lift solely when there is a positive Angle Of Attack. Its advantage is that is slides through the water better with the curve and taper, like fairings for wing struts or wheel pants.
Great information on the 3rd and 4th type rudders.
Any chance you could do a video on why rudders are placed where they are. Seems like a mid, or forward rudder would give a much different feel.
For sailing,
Why not have the rudder attached to the keel?
Edit: guess they have figured this out a long time ago with the full keel hull
Better control and response
What about the directional propellers that can turn in some ships and tug boats?
Think you are talking about bow thrusters.
They only work in really slow speeds, and usually need some time to get ready to be used. Deckhands need to open vents, the hydraulic system needs to build pressure, the engineers have to start enough generators so the ship has a high enough electrical supply, these things are high powered macinery using up a LOT of electricity, then the bridge needs to test and document them before use.
While manouvering slowly, the bow thruster is very useful.
On single propeller ships, the aft pulls to one side (always the same side) when the engine is driven astern. Pair that with a bow truster and you can turn on a dime or even go somewhat sideways.
If you have two propellers and a bow thruster, you can manouver the ship in any dorection you can possibly think of by combining different levels and directions of thrust on each.
What effect does a stalling rudder have on the ship?
It will reduce the effectiveness of the rudder. The rudder will generate less turning force. The rate of turn will be slower and the turning circle will be larger. If the rudder stalls, you are better reducing the angle slightly, then you will generate more force.
Can You tell me why rudder is not in centre line of the vessel on Oliver Perry Hazard?
TY for a great informative video. I vvanted to ask though, vv/the last 2 rudders, you said that they help @ lovv speeds , but vvouldnt they allovv even greater turning @ higher speeds ? Sorry for the stupid question & TY again for the video as I've subscribed.
So on a sailboat its the rudder that one uses to adjust the direction and not the sails?
Another great video.
I just learned some shit from this video. Feels good man.
How about combining a flap-rudder with a fishtail-rudder to increase efficiency even further at slower speeds?
If a boat is floating without any means of propulsion -- that is, its speed is determined only by the speed of the current -- can a rudder change the direction of the boat? If you recall in the movie _The African Queen__ Bogart explained to Katherine Hepburn that it would do no good for her to operate the rudder. They were drifting downstream with the current and the rudder was not able to provide any steering unless the boat was moving faster than the current. Is that true?
nice reversing alarm in the background
I heard that and I thought I was losing my mind.
With the fishtail rudder, wouldn't it create more drag when it is amidships?
Seems that way. I tried looking it up and the answer involves complicated fluid dynamics and way more information on rudders than I ever care to wade through.
Talk about bow and stern thrusters and azipod propellers
And how do you control the rudder which is on the ship's stern (back) ,from the bridge at the ship's Bow (front) ??
Hi
Please tell me can we use a rudder in the raft to make it turn in river without engine?
Quality video👍
Great video 👍🏽
Do you have rudder trim as aircraft have elevator trim?
Does the size of a rudder (lengh) effect the effectivnes of the rudder
man you are the best , videos are awesome, do you have any videos for acts and publications and canadian mods
I have not covered acts and publications yet, as I don't find them as interesting as navigation itself. That's why navigation is the main focus of this channel.
Brother.... Is this theory is correct? Specially about the pressure difference(Bernoulli's principle)?
what does it mean when a rudder stalls? diminished turning effectiveness?
perfect explanation
Great video!
I know this is almost 3 year old video but wouldn't an aerofoil when used in water be a hydrofoil?
Casual navigation: shows diagram of airfoil
Me (aeronautics nerd): :>
Everyone else: :|
So you're saying you're better than everyone else watching this video?
KurryCane he was implying that airfoils are not interesting to most people but even I love this
No mention of Newton's 3rd law of motion. Does it not apply even though it may be to a lesser degree?
The downside of the fishtail rudder would be that it increases drag, correct?
Bull. The airfoiled rudder works on the exact same principles as the squared off rudder. It just does so more efficiently because it has less drag. The velocity differential is still there for either shape.
My RC boat rudder blue paint is wearing off due to the force of water pushing against it when turning. RC boat goes 50MPH or in boat terms 43.5 knots
Great video