Slieve McGalliard wrote:

... As planned, it should be easier for Edward to use as the blade will swing out of the water and cause no drag nor manoeuvring problems while berthing which an auxiliary rudder might. It should be more than powerful enough, even with a fairly small vane.

Perhaps I'm using the exercise to ward off Alzheimer's, if it's not too late.

Cheers, Slieve.

Slieve,
I can't help feeling that both you and David Tyler are spending lots of energy on reinventing something that already works  splendidly.  Btw, the short tiller of that aux. rudder could easily be linked to the main tiller when the windvane is disconnected, and then one would have super harbour manoeuvreability, even in astern. The fact that one locks the main rudder with the vane in use, solves any course stability issues without needing to be clever. Windvane designs tend to be clever enough as they are. 

Arne

PS: this reminds me a bit about aeroplane designers in the thirties who spent lots of ingenuity on designing flying wings. They made it, sort of, but getting the things stable , safe and CG-forgiving (before fly-by-wire) proved to be next to impossible, so the concept was dropped (until the B2-bomber).

Of course you're right Arne, but …...

Don't forget, back in the 60's or 70's I was one of the first group in the world to be cleared Cat III so, in theory, Cat II should be easy. (He says laughing, but with his fingers crossed). In practice I've had this simplified design in my head for over 20 years which works in a cardboard model but which I want to try on a real boat. As planned, it should be easier for Edward to use as the blade will swing out of the water and cause no drag nor manoeuvring problems while berthing which an auxiliary rudder might. It should be more than powerful enough, even with a fairly small vane.

Perhaps I'm using the exercise to ward off Alzheimer's, if it's not too late.

Cheers, Slieve.

It would be interesting to see your latest wind vane drawings, David.

I'm not planning anything special for Amiina, probably a basic pendulum gear, but the aim is to simplify it to the minimum number of parts and materials. Just some ply, string, glue, some cloth and one or two pieces of metal. Idea is cheap, light and easy construction and no metal fittings other than blocks for control lines.

Arne, a QME or Belcher OTG Mk.2 type would probably be fine on Amiina, but a proper pendulum gear is more of a design challenge, particularly with the o/board on the transom, and should give more positive results. Why make life easy when you can also make it difficult?

Cheers, Slieve.

David Tyler wrote:
Can I remind you about the one that I've made for weaverbird? Based on the Hebridean principle, but improved, simplified and made suitable for sub-25ft boats with dinghy-style rudders. It's been working very well, since I added the tweak of an inclined vane axis, so when I get home, I'll make some detailed construction drawings.

Jami Jokinen wrote:

Please, please share this with the rest of us, will you? DIY vane is one of my big worries, as I can't afford a commercial one.

Just checking that you know about the Hebridean. I've written about the construction of mine and made some videos on my blog https://tammynorie.wordpress.com/category/repairs-and-modifications/constructing-the-hebridean

You needn't make the full size one that I have if your boat is small. Chris Boxer on Emmelēne is thinking of a 75% one.

There are some free info online about constructing self-steering, but from my experience I'd say that getting one correct that works in a wide varhttps://tammynorie.wordpress.com/2017/09/04/tammy-emmelene-and-amiina/iety of conditions, and stays working, is a long road.

I believe Edward and Slieve are thinking of a design that is specialised to the split junk rig and takes advantage of the fact that the helm is very close to balanced on all points of sail. I spoke to Edward about this briefly when I met him in Poole and I'm very interested too.

Edit: sorry for the formatting mess. The JRA forums are an utter nightmare to edit from a mobile phone and I can't fix it.