We finally connected the trim tab to the windvane while we were hauled out. Yesterday we launched the boat and discovered that I should have installed a trim tab lock. The wash from the 18" propeller, turned the trim tab while motoring, which in turn affected the rudder. My number 1 priority is to build a trim tab lock this week.
I have thought about an adjustable lock that would enable one to finely adjust the trim tab depending on propeller rpm to create a nearly neutral helm. The other thought is to make a fixed trim tab lock.
Any thoughts on this subject is appreciated.
Thanks for the working solution.
Rod, If you go to Mike Anderson's website, freehandsteering.com Look under photos and you will see his locking device. I made one for my boat some years back. I think Mike Mallory had the first design. It is no more than a couple of flat bronze cheeks on each side of the rudder cheeks with a rotating threaded rod between. In the center of the threaded rod is a double nut brazed together with a stud brazed on top. The stud fits into the groove of the vane arm. By turning the threaded rod (knobs or wing nuts on the ends) the nuts move thus moving the trim tab arm to make it balance any way you want. When sailing, the side cheeks with the threaded arm pivots down so the stud falls out of the arm slot.