Fish fin placement; Twin keel versus quad

One of my next projects is going to be a Fish with a 16" tail and twin keels. In regards to placement, i am confused. It seems that most of the post here utilize a standard quad setup and just put the keels in the rear boxes. Is this fine or is there a particular twin keel only setup? If so, how far should the trailing edge be off the rail? Forward edge off stringer?


I cant’ think of anyone putting there keels in the rear or front box on a quad set-up. I’ve looked at doing that with my fish with the Pavel quads and the keels were not anywhere near where I would like them. That being said, I put my keels with the rear edge in line with the top of the butt crack. Usually, 6 to 6 1/2 inches from the tips and rear edge 1 1/4 from the rail. Single foils I toe-in 1/8 inch with 2 degrees cant. Double foils no toe-in or cant. Check the archives, too. If you are using a box system you will need to adjust the placement of the box because the keels hang off the back of the boxes. Mike