self steering

[rayaldridge]

Gary-- thanks for the post and diagram--

What's the little hemispherical bump at the bottom of the skeg?

[garydierking]

I think it's a zinc anode to prevent electrolysis in the stainless fittings. Note the wire shown connecting the fittings.
I didn't have one fitted and after a few years I found that stainless eating worms had been busy on the bolts.

Gary

[bill broome]

gary d: thx for the pic. i had figured out the basic mechanics, but this gets me a better start on relative size of fin and vane. i also realized while looking at it, that the vane has to be well balanced on it's axle to prevent 'inertia' steering as the hull rolls over a wave.

farjoe, i will try to mount the device on the back of the rudder, with fin and vane on the same axis. this will eliminate most of the connecting link complexity. what remains is just the two selector disks that set the relative angle between tab and vane. it might not work due to the vane having a direct effect on the rudder through weight and windage. then, plan 'b'. and 'c'...

will need devices on both rudders, or at least a quick and easy way to move one to windward rudder. i'm going to try to put pivots above the waterline, initially. make it easier to mount and service at sea. but this might not be a good idea in a really fast boat. i'm going to be a slowish boat, for comfort.

[dialdan]

Hi Bill
How about you lock off the two main rudders and then use your homebuilt windvane with it,s own rudder centrally mounted on your rear beam? Hydrovane and Auto - Helm are two commercially available units that do this quite successfully I believe. Google Hydrovane and look in the photo section.
Al

[bill broome]

i've sketched a preliminary design on my boat blog:

www.sailtherapy.blogspot.com.au

[bill broome]

hmmm, link has been miswritten, no .au.

www. sailtherapy.blogspot.com

[bill broome]

www.sailtherapy.blogspot.com

bound to get it right soon...

[farjoe]

Bill

your sketch is a bit too small for us (or at least me) to understand principle. Can you post a bigger picture?

[dialdan]

Hi Bill
This could be worth a look . www.sailsarana.com/selfsteering.htm

Al

[Chris Bretter]

Wharram have a windvane system that is all wood and seems to work well
James Wharram Designs 40 pounds for the plans

[bill broome]

thx chris. i'll pay for plans as quick as i'll pay for sex: never that desperate. there's no hurry, i'm a hobbyist who enjoys mucking about in the shed as much as sailing. more when it rains.

[bill broome]

farjoe: i haven't figured out how to insert a large pic in this thread, but i have put the sketch in the 'gallery' under multihull self steerer,with some notes.

[Chris Bretter]

I think if you get a look at it you will be able to fabricate one its all wood and very adjustable and cheap

[farjoe]

Originally Posted by bill broome

farjoe: i haven't figured out how to insert a large pic in this thread, but i have put the sketch in the 'gallery' under multihull self steerer,with some notes.

thanks i will have a look

[sandy daugherty]

I don't understand why wind vanes are successful on a tri, and universally useless on catamarans.