fin placement and mounting?

I have an inland chubby 4'0" (old board) It currnetly has two fins placed 12" from the tail. I am looking to add a third fin and looking for advise for the location, how far from the tail.

I have a large collection of old wakeboard fins and so i plan to go that route. What kind of reinforcement would be needed to spread the load to keep from damaging the board. My ideas ranged from just washers to a metal plate, to routering a channel in the top and inserting a plastic block for the screw holes.

I had one of those long long ago. It has o'fish'l fin boxes? There is no set screw - just a tab at the front of the box that holds the rail fins in? If my memory serves me correctly - and that is a HUGE risk! That board was made somewhere other than the Cobra factory and it doesn't have the wood veneer, nor the core of low density foam. I swear I can still see the foam as about 8 pound density PolyU. If that is the case, you can probably get away with sleeves through the board that the 1/4 - 20 would pass through (I've used 1/4" id brass tube, glue that in place) and a washer on the top. You don't need to cinch that down tight, just enough to hold it in place. The alignment studs on the fin - drill holes oversize and then fill in with a dab of epoxy. But don't STAND on that fin!

My 2 cents.

Oh...tail of the fin between 2 and 4 inches up from the tail.

thanks i hadn't though of sleeves, is there dis/advantages of placing the center fin forward of back.

WAlove,

I'm not sure I understand your question - the middle fin in front of the rails fins?

sorry, forward or back. You gave a range of 2 to 4 in. I was wondering what difference it would make?

Thanks for clarifying for me. Everything else remaining the same - The further back the middle or trailer fin is, the more "tracky" or less loose the tail will feel. Conversely, the further forward that fin is, the LESS tracky or more loose the tail will feel. It's purely a subjective thing. If you aren't quite sure where you want the fin to be, before making it permanent, try tacking it on with some 5 min epoxy or even the thick supermarket grade superglue (also the debonder works well). Just a dab on the fin, enough to hold it in place without preventing it from being removed with a good twist of the wrist, or the use of the debonder. You can play with placement out on the boat and when you have it wired, mark it for permanent placement later.

good idea, i'll try that the next time im on the water