this was an idea i'll share that come up when my boat porpoised. why dont u fabricate a trim tab with a hinge and angled/loaded by a spring or rubber. i have read that most people here had an angle bar tab which is bent and rebent after a while due to ground running. if it was spring loaded just enough not to retract from the force of the water stream on water running and will flex enough against the ground then you'll have a nice working trim tab.
one very possible advantage to this scheme is that you may be able to make the tab self adjusting in the water i.e. the tab retracts in respect to speed. this is a very fact that you'll only need a fraction of the tab angle at high speed compared to that at lower speed.
therefore, the tab is steep angled at low speed and self adjusts with speed in the water while totally retracts upon ground running and resets upon return to water running.
i could have made this type of tab but my mini VW airboat that porpoised had a fiberglass laminated tab that do the function. it flexes as needed but it wont last even if i just run dry ocassionally.
by the way, i think stainless would be best.... if it works, just send me a case of beer!
