Thinking of building a self steering wind vane?

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35mm

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I'm thinking of building a self steering wind vane system. I prefer the servo pendulum system and plan to build it based on that. Anyone tried that or have any ideas? I'm not sure on the mechanism to make the vane turn the servo?
 
I have some spare components from a Navik gear, and a helicopter tail rotor blade, which could be cobbled together - with a 'suitable system of levers' - into a servo-pendulum gear. PM me if interested.
 
Worth considering when I have done all the million & one other tasks.Shall first of all check out the self steering tiller systems using blocks & ropes shown on Youtube.
The early circumnavigators built their own,can't be exactly rocket science.
 
35mm said:
I'm thinking of building a self steering wind vane system. I prefer the servo pendulum system and plan to build it based on that. Anyone tried that or have any ideas? I'm not sure on the mechanism to make the vane turn the servo?
Click to expand...

You'd do well to read Peter Forthmann's book if you haven't done so, downloadable free at: http://windpilot.com/

Most if not all recent servo systems use a short crank and bevel gears to translate the up-and-down motion from a (horizontal axis) vane into rotation of the servo oar. The gears offer a degree of yaw damping, as does the 15 degree angle of the vane pivot's 'horizontal' axis. Earlier servo systems used vertical axis vanes, which looks more logical but worked less well.
 
35mm said:
I'm thinking of building a self steering wind vane system. I prefer the servo pendulum system and plan to build it based on that. Anyone tried that or have any ideas? I'm not sure on the mechanism to make the vane turn the servo?
Click to expand...

This is something I had been in the process of doing for my Hurley 22, however having purchased a H30/90 it got left in limbo for a 2 year restoration/ refit.
I got a lot of good information from this site http://www.cruisenews.net/forum/viewforum.php?f=62
My design was based on a Walt Murray 20/20 home build system. Many people built them and sailed thousands of miles with variations of them. Sadly Walt Murray died in 2006 so his designs may be a bit difficult to track down? Also Jan Elkema a good friend of Walt’s, has had really good results with his concept for an Upside Down Vane. Suggest you search internet for anything relating to these two people?
If all else fails I have some details and photos on my computer somewhere, which I may be able to dig out of the Walt Murray 20/20 Wind Vane. Also check out Sheet- to- Tiller S/S , but it does have loads of string in the cockpit some may not suit? You don’t say what size boat it would be use on. So my not be suitable? I have thought of altering my already 2/3rds finished project to suit the new boat, but need time to do so?
Best of luck with it.
 
The Walt Murray designs use a fork and lever linkage which always struck me as vulnerable - if I can bend it into shape, I assume other influences can bend it out of shape... Other designs use a 2:1 bevel gear linkage, these can be sourced quite easily on t'interweb. Although they may be the easier option, many gears are a bit on the small side and require careful setting up for best backlash to allow smooth movement. There are larger gears, at comensurate higher prices which are probably worth the extra. As anexample, Seafeather offer the choice of acetal gears or stainless depending on whether you intend to do coastal or ocean cruising .

A lever arm on the vane transmits a vertical movement down to the base, where the chosen linkage converts it to a rotary movement again to turn the servo blade.

It is possible to use sheaves and lines to transmit the motion, but has the limitation that adjustment cannot be allowed to cross the lines, so at the limit, the head must be turned the long way round. A good example is the Jan Alkeema USD vane.

Rob.
 
rob2 said:
The Walt Murray designs use a fork and lever linkage which always struck me as vulnerable - if I can bend it into shape, I assume other influences can bend it out of shape... Other designs use a 2:1 bevel gear linkage, these can be sourced quite easily on t'interweb. Although they may be the easier option, many gears are a bit on the small side and require careful setting up for best backlash to allow smooth movement. There are larger gears, at comensurate higher prices which are probably worth the extra. As anexample, Seafeather offer the choice of acetal gears or stainless depending on whether you intend to do coastal or ocean cruising .

A lever arm on the vane transmits a vertical movement down to the base, where the chosen linkage converts it to a rotary movement again to turn the servo blade.

It is possible to use sheaves and lines to transmit the motion, but has the limitation that adjustment cannot be allowed to cross the lines, so at the limit, the head must be turned the long way round. A good example is the Jan Alkeema USD vane.

Rob.
Click to expand...

Hi Rob what you say is correct about Walts design. But it gives you an idea where to start designing one. I took the basic design for the vane carrier, used Jans Alkema’s USD Vane arrangement and used Stainless steel output shafts, set in Delrin bearing races, set on 2-1 ration 2” bevel gear. All gears and races set in 50mm S/S tube.
 
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Bear in mind that the size of the sail and rudder are dependant on the length and weight of your boat. If you don't get it right the gear will understeer or oversteer, effectively a waste of time and money.
 
KellysEye said:
Bear in mind that the size of the sail and rudder are dependant on the length and weight of your boat. If you don't get it right the gear will understeer or oversteer, effectively a waste of time and money.
Click to expand...

The posts seem to be about servo-pendulum systems which don't have a rudder, but a pendulum oar or blade. On the whole the oar and vane are generally remarkably indifferent to boat size: in many cases the same system can steer anything from, say, 30 to 60 feet. What varies most (essentially because of greater freeboard at the transom) is the length of the pendulum shaft. Larger boats obviously generate higher steering forces (and need them) simply because speed through the water and thus over the pendulum oar is greater.
 
'Selfsteering for Yachts', by Gerard Dijkstra is well out of print but everything you need to understand on linkages is in it. Try secondhand searches.
Some of the older amateurish books ( and this one dates from 1979) are ( or were:D) IMO plain wrong, misleading, indicativd of their authors limited comprehension of the subtleties involved. IMO of course
 
xeitosaphil said:
This is something I had been in the process of doing for my Hurley 22, however having purchased a H30/90 it got left in limbo for a 2 year restoration/ refit.
I got a lot of good information from this site http://www.cruisenews.net/forum/viewforum.php?f=62
My design was based on a Walt Murray 20/20 home build system. Many people built them and sailed thousands of miles with variations of them. Sadly Walt Murray died in 2006 so his designs may be a bit difficult to track down? Also Jan Elkema a good friend of Walt’s, has had really good results with his concept for an Upside Down Vane. Suggest you search internet for anything relating to these two people?
If all else fails I have some details and photos on my computer somewhere, which I may be able to dig out of the Walt Murray 20/20 Wind Vane. Also check out Sheet- to- Tiller S/S , but it does have loads of string in the cockpit some may not suit? You don’t say what size boat it would be use on. So my not be suitable? I have thought of altering my already 2/3rds finished project to suit the new boat, but need time to do so?
Best of luck with it.
Click to expand...

Walt Murray's designs are still available online. Hunt down the threads on the Cruisenews forum and you will find the link. I'm Ramona on that forum and pictures of my latest bit of kit are in the 3rd thread down. My first windvane was a SS version of a Walt Murray design with the 45 degree crank. Steered well but wandered a bit in light winds downwind. The latest unit has bevelled gears and these give good feedback and the yacht will steer downwind, dead straight in less than 5 knots of wind. Much more comforting when flying a spinnaker singlehanded. Up wind it steers far better than any helmsman. Download the free book by Peter Christian Forthmann, Self Steering under Sail. It has comparison charts of all the major builders with all the dimensions of shafts, blades etc, bearing types. Ratios and dimensions are pretty much all the same now. Delrin bevel gears, stainless ball bearings and pretty much anything required to build these units is freely available online and cheap. I doubt I spent more than $200 on my unit and that's going crazy buying the best materials.
Study a few Youtube videos and get some ideas. This is my old unit. https://www.youtube.com/watch?v=U66-R0i2c20*feature=plcp

Interestingly the final version of that unit looked nothing like the video. I should get off my butt and put a new one up of my latest creation.
 
Blueboatman said:
'Selfsteering for Yachts', by Gerard Dijkstra is well out of print but everything you need to understand on linkages is in it. Try secondhand searches.
Some of the older amateurish books ( and this one dates from 1979) are ( or were:D) IMO plain wrong, misleading, indicativd of their authors limited comprehension of the subtleties involved. IMO of course
Click to expand...


A well illustrated book.... lots of pictures and diagrams expaling how various systems work.

Second hand copies are available ... Title may actually be 'Self Steering for Sailboats' ... maybe that was the American edition but search Amazon and eBay for Gerard Dijkstra and you will find it
 
Look at the The Amateur Yacht Research Society The Amateur Yacht Research Society. Publication 127 is on self steering. They also have numerous publications on self-steering in Catalyst - their journal. I couldn't find the one I was looking for on the upside-down gear. Horizontal pivot vane with the pivot at the top. It was quite convincing and simple. Claim is that power increases with angle of heel whereas with the bottom pivot it decreases. Think it was a Dutchman called Alkema or something like that who invented it.
 
35mm said:
I'm thinking of building a self steering wind vane system. I prefer the servo pendulum system and plan to build it based on that. Anyone tried that or have any ideas? I'm not sure on the mechanism to make the vane turn the servo?
Click to expand...

have a top half of an hydrovane unit if you want it,can pick it up or arange pick up
has rudder part missing
 
. . . I shall first of all check out the self steering tiller systems using blocks, elastic, ropes, etc shown on Youtube.
Click to expand...

You're free to do that, but make sure you appreciate the difference.

A good self steering gear is like having the best helmsman with you at all times, someone who is incredibly strong and constantly alert, who never gets seasick, or hungry, or tired and can probably do a better job than most 'good' human helmsman.

Alternatively, the sheet to tiller systems can be made to work at times, but . . .
it's like have a disinterested teenager helming
who's got weak puny arms
and is drunk
and suffers from Narcolepsy
 
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