Worm and wormwheel latch gear that could be used for a pendulum servo or trim tab self steering gear. The worm carriage slides fore and aft, with spring detents. The visible cord is pulled to disengage, and both sides of the course adjusting line are pulled to engage. The vaneshaft is ⅝" diameter x 2ft 6in long, similar to the Hasler SP gear. I designed and made it many years ago, but never used it.

Anonymous wrote:

Worm and wormwheel latch gear that could be used for a pendulum servo or trim tab self steering gear. The worm carriage slides fore and aft, with spring detents. The visible cord is pulled to disengage, and both sides of the course adjusting line are pulled to engage. The vaneshaft is ⅝" diameter x 2ft 6in long, similar to the Hasler SP gear. I designed and made it many years ago, but never used it.

Hello David, is there any reason why, with modification, it can't be adapted to work with a horizontal axis vane?

Anonymous wrote:

I can't see any possible, let alone desirable, way of doing that, Asmat. Can you?

No, David. Looking at your mechanism again more carefully, nor can I. I'm thinking of designing a replacement for the Hebridean vane gear aboard my 20ft Coromandel which works well enough, but occupies the whole of the Cook's berth, dismantled and stowed away.

Anonymous wrote:

But why reinvent the wheel?!

Yes, that is an improvement over Emmelène's somewhat crudely engineered Hebridean. I admired Weaverbird's most elegant gear at the Brixham regatta a few years ago.

Emmelène will probably be limited to coastwise sailing in future, so I don't expect to leave the self - steering in charge while off watch. With her split junk rig, she is so well balanced I think a version of Arne's "Otto" windvane acting directly on "Malena's" rudder may be sufficient for my needs. It would certainly need a much bigger vane than your servo pendulum gear, which I don't see as a disadvantage.

Anonymous wrote:

What size windvane do you have in mind Asmat?

Best regards,

Antoine

Arne's "Otto" windvane was 1.2m (4ft) tall. I will use this as a starting point, leaving scope for reduction if this is found desirable. I envisage being able to lock it vertically to act as a riding sail, helping to prevent the sheering about at anchor which junks tend to exhibit.