Thanks for all the great design info!..it just came a little late. First shortboard shaping experience. I have a 5’9" x 21 1/2 x 2 5/8 fish. Plan on using Rainbow Bamboo twin keel fins. With this setup the base of the fins will be 10 3/4" from tail, tip of fin to tail 8 1/8". Fins toed 2" off of nose. Tail width is 17 1/4 @ 12". Crack is about 5 1/2". Flat to slight V bottom. Now think (after discovering this forum) the fin boxes were placed too far forward. How will this effect the performance of the board? What should/can be done? …hopefully not just a killer piece of art for the wall. Need help.
Yes, too far forward. Line up the rear edge with the top of the crack and the tips of the pins. Usually, 1 1/8 to 1 1/4 inches off the rail. You can move them up to around 6 1/2,too. I would only toe them in about 1/8th inch. I don’t know where that puts them in relation to the nose. I’ve never used that method for fin toe in. Mike
If it were my board I’d consider mounting another pair of boxes to put the tips of the keel even with the buttcrack and using the existing box for a small bonzer runner or twinzer leader fin. The trick with those is to use leader fins with a lot of cant. That’s the fin setup Bing uses for their Synchronizer model (you can see it on their website). I’ve been using it on my fish (same bottom contour as yours) and it’s by far my favorite fin setup for that type of board. It’s quite loose for how much fin area is involved and it’s rock solid and drama free going backside.
You posted tumbnails instead of full size pics and from the angle I can’t quite tell what kinds of boxes you’re using. Getting a leaderfin with the right amount of cant may be tough. You’re probably looking at having them custom made.