Thoughts on this Vane Design for Self Steering

[Tom Stormcrowe]

I tried to use the KISS principle. It's a simplified Hassler influenced idea. The sketch is sloppy, sorry, but then again, I'm not a draftsman. I'm interested if you think it'll work well enough for a 19' boat. It's a simple tiller puller with a vane and uses the rudder itself rather than a secondary rudder.

[Sven]

The drawings are a bit small but if they show a vertical axis windvane that pulls on the main tiller via steering lines it will not work. The forces a vertical windvane can provide are way too small to move an normal boat rudder.

This is why vertical vanes usually are big and only operate servo pendulums or fully balanced auxiliary rudders.

[Tom Stormcrowe]

OK, thanks, Sven. Allrighty, then, refinement time. Looks like I need to read more on the subject. It looked good in theory, but so do a lot of other things, which was why I asked for extra eyes.

[Jim Cate]

G'Day Tom,

Unfortunately, unless your rudder has lots of balance area, the above comment is correct.

I recommend highly that you find a copy of "Self Steering for small sailboats" (approximate title) by John Letcher. It does a good job of explaining the theory and practice of all sorts of self steering, including sheet-to-tiller (which might well do everything you need).

Cheers,

Jim

[bruce smith]

19 footer? lets check out the boat. full keel/fin /cb?
outboard rudder?
For kiss, think trim tab.

[Tom Stormcrowe]

Originally Posted by bruce smith

19 footer? lets check out the boat. full keel/fin /cb?
outboard rudder?
For kiss, think trim tab.

Fixed shoals draft keel. Here's my boat. She's got a transom pintled rudder, by the way.

The last image isn't my boat, but it shows the rudder, etc.

[bruce smith]

I think your simplest form of mechanipickle steering will involve a wee trim tab.
A trim tab works like a tiller , only on backwards . The vane moves the tab, the tab moves the rudder.
Hassler servo is much more power , but not simple and probably overkill for the boat , which, looking at the longish keel , may just take a steerer nicely.

[Jim Cate]

Nice looking little boat, Tom!

Unfortunately, none of the pix really show the shape of the rudder nor if it is at all balanced. If it is unbalanced, then a trim tab alone is unlikely to develop enough torque to steer her. One solution is to add balance area to the blade. Another is to put the trim tab on long extensions aft of the trailing edge of the rudder (this multiplies the torque developed at the expense of an awkward construction and added drag).

But really, having now seen the nature of your boat, I would suggest playing with sheet-to-tiller steering. For the cost of a few feet of surgical rubber tubing, a small block or two and some light cordage you can undoubtedly achieve at least some degree of self steering and possibly quite a useful degree. Years ago I did so on a Catalina 22 which has a much less seakindly hull shape than your boat. That system is not as good as a proper vane, but costs almost nothing and can be rigged in a few minutes.

Good luck and enjoy your experimentation.

Cheers,

Jim

[gjordan]

See if you can find a FOLKBOAT forum. Many of them ( and Contessa 26s) use a Quartermaster wind vane that is great for a transome hung rudder. You would have to make adjustments to the design to accomidate the reverse transome, but the principal would work. It simply clamps on the rudder head and had a paddle behind the rudder. For your reverse transome you could rig a U-joint to a trim tab on your rudder. It was simple and reliable. Much less complicated than a Hasler. __Good Luck._____Grant.

[SVTatia]

You can get all the information you need here (page 33 onwards):

http://windpilot.com/n/pdf/bookeng.pdf

[Tom Stormcrowe]

Originally Posted by SVTatia

You can get all the information you need here (page 33 onwards):

http://windpilot.com/n/pdf/bookeng.pdf

Thanks very much! Outstanding info.

[gjordan]

Lots of good information on the link givin, but nothing on the much simpler Quartermaster type vane. The OP is not asking about a 40 foot boat. He is asking about a 19 foot boat that the self steering needs are very differant than a large boat. Dont over complicate the problem._____Grant.

[Tom Stormcrowe]

I'm now thinking a scaled down version of this:

Self-Steering Gear -- Build a trim-tab based wind vane or autopilot self-steering system for your boat

There's a free PDF in there that details the design process and necessary calculations. It looks like I may be able to build a very simple, lightweight and effective system.

[Adelie]

If you want a cheap DIY windvane look here:
Walt Murray's website | Mister Vee wind vane self steering
Model 20-20B

Walt died but his website has been mirrored.

Alternatively try sheet to tiller self-steering. It's not as convenient as a windvane since different points of sail require different setups but it's cheaper than anything else other than getting the boat to balance for long periods of time.

FoolishMuseSelfSteering.wmv - YouTube

http://sfbaysss.org/tipsbook/SinglehandedTips.pdf?id=1
Sheet-to-Tiller Self Steering
A Pearson Ariel Page

There are several books that touch on sheet to tiller arrangements including JSLetchers book. But the bible of sheet to tiller is Lee Woas's book that is just about sheet to tiller methods. If you try one method and it doesn't work for your boat on a specific point of sail, he has 2 or 3 more to try. Pricey book though, should set you back a significant part of $100.

The Woas heirs are in FL and one of these days when I get motivated I am going to drop them a line and see if they are interested in doing a re-issue of his book.

[SkiprJohn]

The two books I have on self steering are Self Steering for Sailing Craft by John S. Letcher, Jr. and Wind-Vane Self-Steering How to plan and make your own by Bill Belcher. They cover a lot of ground.
I agree with the trim tab for your particular application.
kind regards,