Iv'e already made up my mind through doing alot of listening and reading  to try a set of hydrofoil fins on my 35 hp mariner.  On the anti cavitation plate where they mount is what I believe is an anodizer.??  Can I move it more forward on the anti cavitation plate, or should I notch out the hydro foil fin so it fits around it.  

Can someone please educate me as to what that little gizzywhopper is actually all about.  I'm under the assumption that it somehow prevents corrosion, but locally the answers I get are conflicting.  

My thanks to anyone that can help me out.

If the anodize has a small offset fin then it serves 2 proposes.  The material it is made out of causes it to be a sacrificial anode thereby helping to prevent rust elsewhere on the motor.  The fin portion is to help straighten out and tendency your motor hat to turning on its own because of prop rotation and torque.

The ones I have seen have a large bolt running through the center and don't look easy to move.  Probably better to cut the hydrofoil around it.

The one piece fins goes on top of the cavitation plate. Or the two piece ones the cavitation plate fits inside of the fin. I have never seen one the hits the anode.

Thanks for the help guys.  I have 1 peice fins that are grooved so as to fit over and under the cavitaton plate for thru bolt mounting.

as for the "anodizer", it's about 1 1/4" x 2" and has 2 1/4" thru bolts.