Design features of a trim tab wind vane for accurate steering of a yacht ( DIY homebuild )

Sailing in awesome weather with my old boat and the wind vane i have now converted to servo pendulum. This was its first trip and i was still testing bungee tensions and well everything so was pretty happy with this. The boat could steer itself in these conditions so its not the biggest acheivement in the world but it still was a remarkable accurate windvane. So i thought i would share some of the points that made it work well so you when you make yours it will hopefully save you all some time and money. Shame i didnt take more videos when it was finished, apologize and fair winds

[@Tampo-tiger]

Genius idea, so carefully thought out. Thank you.

[@emmottataolcom]

Bravo! finally somebody had the foresight to mount the vane on the pushpit rail and use a morse cable to move the trimtab! where did you find the morse cable long enough?

[@nonlinearplasma1370]

Morse cables are sold everywhere and at any length as they are heavily used as gear and throttle controls on yachts and speed boats. Appreciate the comment, many thanks.

[@markclayton2614]

I saw this about a year ago and thought it was a very good design. Hoping to replicate it. Would it be possible to get drawings, material list, info that would help?

[@nonlinearplasma1370]

I dont have any drawings, sorry, i have moved on to a much more intense project and i dont have time to focus on an old invention that isnt relative to the Non Linear Plasma Reactor. I have some new video footage from the last 15000nm i have done. I just need to do some editing of different videos and make one decent video to post. I will try to do that soon for you and i maybe include some pictures so you can screen grab them from the video. Materials, obviously the morse cable is a cheap connection method. They last a long time if used a lot. Bearing carries are simple self aligning plastic pillar blocks. Shape some tool steel to the shape of a metal bearing and use it to cut a self aligning and self lubricating plastic bush on a lathe. I still have the tool if you wish me to do it for you, if you dont have a lathe.

[@markclayton2614]

@@nonlinearplasma1370 I , like many, would really like to see the video for sure. Will be a big help. No lathe here. Would appreciate the help but don’t want to be a bother. Thanks for the kind reply.

[@johnmajewski1065]

I like how it seems so simple, how do you think it would work on a bigger boat? Say 15 meter 8.5-ton displacement, my rudders trailing edge is flush with the stern of my boat?

[@nonlinearplasma1370]

As long as your trim tab is big enough to move the rudder and the vane is sized to move the trim tab, it will work on any size boat. The only way to solve the problem of the rudder under the boat is to bolt the mounts for the trim tab under the water line with an over hang so when the rudder is at full lock the trim tab doesnt come in contact with the transom. It can be a bit of trail and error so make as many parts as you can that are interchangable with larger and smaller parts/linkages. I had to put a 15-20* bend just above my trim tab so as to kick the bottom out to get the trim tab into the water flow faster. This worked very well.

[@johnmajewski1065]

@@nonlinearplasma1370 Thank you for this timely reply -This sounds like a wonderful project I would like to try. I tried to find your plans on FB found some articles lots on other wind vane gear tests and on other subjects but no information other than the video demo. Can you send me a link? Thanks for your pioneering engineering work. SV. Skoiern IV John

[@nonlinearplasma1370]

@@johnmajewski1065 facebook.com/groups/145491262806631/?ref=share Try that link john. Might take a few days for the admin to approve you. There isnt many photos of my old vane, but the new one which is the same head unit converted to run a servo pendulum has plenty pic up there to see. Look for a scott.

[@oldfrisianmachineshop2168]

Very nice!... I'm curious about the resistance caused by the Morse cable... does it affect the sensibility of the whole setup ?

[@nonlinearplasma1370]

They are actully surprisingly friction free so long as you keep the bend radius reasonably big. Manufactured units generally use very large rudders on there wind vanes because they have to steer long keeled yachts which have zero rudder infront of the pivot point, most modern yachts are design with a rudder ratio of 5:1 (ie for ever 5" behind the pivot 1" will go infront of the pivot point) this acts like power steering and means the trim tab can be made much smaller. This also put less resistance on the morse cable or any other linkage and keeps the response speed high. Much appreciated.

[@oldfrisianmachineshop2168]

@@nonlinearplasma1370 Many thanks for your reply. I'm currently working on plans to make a pendulum type windsteering system for my boat and I think using a Morse cable to control the pendulum rudder will make things much easyer instead of using a gear setup! Again thanks 👍

[@arekkaniewski4442]

How do you attach vane rude to your rudder?

[@nonlinearplasma1370]

It's a morse cable, the same as used on the gear selector. You can buy them at any Chandler. So spares should never be a problem

[@arekkaniewski4442]

Hi , sorry what I meant is how the auxiliary rudder or trim tab attaches to the boat rudder. I'm assuming it's attached by pointless to the main rudder.

[@nonlinearplasma1370]

Apologies i read that wrong. It was also very simply. I put pictures up on the fb page homemade self steering windvane. But basically I used bushes out off the same plastic as the bushes in the self aligning bearing holders. Then i welded stainless steel steam pipe clamps to flat bar which was screwed onto the back of the rudder. This meant everything could be easily removed for racing and cleaning.

[@arekkaniewski4442]

Thanks for the explanation. I will have a look at the fb page as well. Fair winds

[@gabrielfusaru1211]

What are the wind vane and trim tab leverage ratio?

[@nonlinearplasma1370]

The workable arc of the morse cable needs to be pretty precise. My vane arm is 60mm and the trim tab is about 150mm on this trim tab set up. I changed to a servo pendulum and it now has the same 60mm vane arm with the new rudder reduced to 100mm. The vane arm can also be reduced to 50mm for different conditions.

[@robertbishop3055]

what/where is the "fb page"? I would really like to see more detail on how you built this, it looks great, please and thanks

[@nonlinearplasma1370]

Hi Robert, the fb page is call HSSWV, (homemade self steering wind vane) it is not my page but i will be easy to find once you have been accepted, look forward to chatting once you have had a look around, regards Scott