So far my attempts to make a self-steering tiller guide have failed. The problem is twofold. Firstly I don't want to attach cleats and things to the tiller and secondly I don't want to take off the decorative ropework on the tiller.

This is the mk2 tiller guide and it looked a little cumbersome but I thought that it would work.

It didn't and this photo shows why. The ropework on the end of the tiller is larger in diameter than the rest.

There is no way that this is going to fit so the mk2 version was abandoned for this reason.

Additionally, this version didn't allow for a good lead into the cleat. As you can see, from the pin to the cleat isn't inline with the cleat itself but at an angle and that could affect the holding power of the cleat adversely.

So, I started mk3. This time I'm confident enough to make it for real with some prototyping along the way to check the measurements. The body of the guide is to be made from some Walnut that I had left over from another project and this is the start.

This contraption will form a bridge over the rope at the end of the tiller.

Rounded and sanded a bit to make it look a bit better.

This is how the guide will sit on the tiller. As you can see it clears the ropework easily and is a lot less cumbersome than the previous versions.

I measured the guide and then laid out the the cleat and pins on a piece of scrap wood to check that my calculations were correct. 

The marking out only had to be done once as I seem to have everything correctly thought out.

The 4mm line leads from one side...

...or the other without problem.

This is the finished top half of the guide with both pin and cleat sets fitted.

The guide isn't too tall or cumbersome but does need to be fixed to the tiller in some fashion.

And the answer to that is another section of Walnut like the top but underneath the tiller.

The two halves of the guide will be bolted together with two bolts going through holes in the tiller. Well, drop nose pins to be correct, not bolts, but the effect will be the same. The pins will be fixed to the top half in a recess under the cleats. I'll also fit some shaping pieces to both top and bottom sections, either from Walnut or from epoxy to make the parts sit more tightly on the tiller.

I've ordered the drop nose pins and I'll carry on with this project when they arrive.

Time for a cup of tea.