Small I/O bowriders without power steering and some outboards without power steering that I have seen have small adjustable fins above the prop that keep the boat from pulling one direction from the prop rotation. I was wondering why these aren't on boats with power steering? I believe I can put one on my Bravo I outdrive? Since my boat will run in the 60's I'm worried about the power steering belt breaking or the steering cable breaking and snapping the drive to one side and rolling the boat over or at least throwing us out. I don't want to spend the money for hydraulic steering or steering stabilizers I thought maybe this was a dirt cheap alternative? Would this work and why aren't they on all boats? I can't imagine speed being effected? Thanks.

Those are just trim tabs, used to prevent single engine boats from leaning opposite direction from prop rotation while at speed. Nothing to do with steering or steering control. Prop wash hits the tab and puts force on side of tab to stand boat back up. Hull design may require one or not. My Formula with SBC did not need one so I had the flat plate version.

From my limited experience; if my tab is not adjusted properly it will almost pull the wheel out of my hands at top speed. If I just let go of the wheel it would spin it to full lock almost instantly and probably flip the boat. When its properly adjusted I can steer with two fingers at WOT. This is in a small bowrider with a 4-cylinder and no power steering. Hard to believe that little fin will make such a difference but it does in my boat...