Help…I have only ever made retro longboards with a single fin set up but now I have made a short board with a stuident and we are at the stage of placing the fins and I am clueless here. Is there any kind of formula for calculating the angle of the side fins?? Distance from the tail? What is the general angle of “cant” on the side fins??
regards
best to use a board you like as a reference, near the same size and shape. exact dimensions will help. i bet greenlight has some sort of chart…
Depending on length; 3-3 1/2" to the back of the fin base from the the tail for a center fin. 11-11 1/2" for side fins from the tail to the back of the fin base for an average shortboard in the six foot range. Cant can run 2, 4, 6 or even 8 degrees. Toe is usually somewhere in the 1/4"--1/8" OR 3/8" range. In other words: The front or leading edge of the fin is "toed in" 1/8" toward the center of the board as opposed to the rear or trailing edge. I mark my side fins by measuring off the center of the blank. If your shaped blank is symetrical both side fins will be the same distance from the rail. If not you may need to true up your outline. Whatever you do don't cross up your fins. Make sure they come out just to the rail side of the of the stringer at the nose. I make a pencil dot at the back or trailing edge of the fin base and then draw a straight four inch line thru to the front of the base. The pencil line makes sure there are no screw ups at the glass shop. For cant use an adjustable square on another board for referance. Lowel
Oh! It should go without saying; Always "Eye-ball" it before you start drilling or routing. If it doesn't look right; give it a second look. A "shaper's square" will make marking everything easy, but a carpenters square works as well.