Twinfin placement

Hi everybody, Could anyone help, I have shaped my first twinfin or at the moment no fin. With dimensions of L 5’11 W 203/4 N 15 T 161/2 but I have no reference for fin placement or size of fins. Look forward to hearing from you, thanks Dave.

About 10" up and bring them off the rail about 1 3/4"(back of fin) to give it a bit more hold in, toe them out about 2" off the tip of the stringer(at nose) this is a pretty safe starting point for the measurements that you described, once you ride it think of how it feels and what you could do too the fins to make it better IE: lay the template back - more drive less pivot or viceversa, toe in - sharper turns less drive or viceversa, these are just some of the variants of trying to work out what is right for the shape that you created, the search begins. KR

Should a true twin fin have the fins toed in or straight in line with the stringer ?

I have a 5’11 x 14 x 20 x 14 5/8 late 70’s style twin fin remake shaped by Glen Minami and the board is working unreal in 3 foot hawaiian size waves and under. The side fins has a base of 4 7/8 x 5 1/2 deep placed 10 1/4 up from the tips of the swallow with the trailing edge of the fins 1 1/8 from the rail. Don’t know the exact toe in or fin cant but it looks similar to a modern thruster. Aloha

I went to that Mandala Fish festival in Pacifica last sunday and rode a swallow tail with double stringers and parrell keeled fins; it worked. Still the tide was unfavorable at the time, mostly closeouts, but the bottom turns felt good. It could have just been a fluke. This board had a fairly narrow tail, maybe 16 or so inches and this left those two parrell fins around 6-9 inches apart.