With all the small surf we’ve been having this summer, a lot of LBers are switching out their 2+1 set-up for a nice single-fin…but now where does that fin go? Fin placement has a major impact on the performance of any surfboard. Many surfers don’t realize this and simply leave their fin wherever it was placed when they bought their board. Or, they just place the fin anywhere in the box, assuming that its location is unimportant. The location of the fin relative to the tail can impact both speed and turning. For single-fin surfboards, some shapers recommend that the trailing edge of the fin be placed 8-1/2” from the tail, and then adjusted forward or backward from there in ¼” increments until the desired performance is achieved. Bill Thrailkill is a master shaper who shaped for both Hansen Surfboards and Hobie Surfboards in the late-60s and the 70s. He teaches people to lay the fin flat on the bottom of the board at the tail, with the base of the fin on the stringer and the tip hanging over the rail. Then he instructs people to slowly slide the fin along the stringer until 20%-30% of the tip hangs over the rail. This is the spot to locate the fin, and if you have a center fin box, you can adjust from there to your liking. What I like about Bill’s approach is that it automatically accounts for different fin depths and tail widths.