SandS said..
Ive been sniffing around for something second hand as well .
But may be the best way would be to fabricate something ? but are there any good shop drawings around for something suitable for wheel steering ?
First vane I built was a Walt Murray design. These are Z crank units and will do the job fine but if you have access to a lathe I would recommend using bevel gears. Walt has passed away but you can find all his drawings on this site. These designs are built using pvc pipes but can also be plywood or SS steel.
https://windvaneselfsteering.com/walt-murrays-website. All the major manufactures use the same dimensions, ratios and lever ratios so you can too. The differences are how the oar rotate and pivots. Once you understand how it works then it is just a matter of what suits your manufacturing skills.
Wheel steering is a problem and not as easy or effective as a tiller. The drum and clutch set up is the usual method but if you have an emergency tiller head then a short tiller pointing aft would be my choice.
This is my earlier unit from 7 years ago. Made mostly from plumbing parts. The Z crank is visible but the quality of the video is poor.
This is my current unit but even this one has been modified since I made the video 4 years ago! The gears are now brass instead of Delrin and the "tiller is now SS tube.