i am at the fin placement stage of a eps/balsa semi gun project i am working on. 7’6, 19" wide, 12" wide @ 12" from pinny tail, basically for 10’ north shore, jacos, leftovers, alligators etc… going to go with future boxes (any suggestions on fins? i was thinking glass F5s) any how i came up with trailer up 3 3/4". fronts up 13" in 1 1/8 from rail (thats 5" from center) toed 3/16’s… first board have made in this size and don’t have any survivors at the moment to look at and since it is 11:00pm thought i should stop before i made a mistake…measure twice asks once
Go single, and switch to a FU box. Set it up so that the leading edge of the fin is 12" up from the tail when it is centered in the box. I’d use a 7.5" to 8" fin. You won’t be disappointed.
i have tried the slap a single fin on the thruster shape in the past and have always been bummed… don’t get me wrong, i love a good single fin from time to time but i have never had any luck with a thruster shape and a single fin. i like my singles to have more volume and vee… and also this board is replacing a workhorse that i had for many many years… it finally snapped and i had to ditch the tail section befor a nasty trip over some rocks after a long swim in… it was a Brian Bulkely from around 95’, gosh i miss that board…
Those placements are fine. You should consider red-x boxes. You will have a 3/4 " adjustment with that system and mega fin templet choices. I have all the stuff to do it also. On epoxy I place them after the second coat of epoxy, pre sanded board.
My favorite thruster guns have glass ons, with rail fins fully toed in, but slightly shorter in chord length than a shortboard thruster fin. And, a normal chord length rear fin. All fins same depth and rake. And make sure the fins mount very STIFFLY to the board. I’ve always preferred glass-on fins on guns, but would rather try Red-X than Futures or FCS.
Singles on big waves are alright, but I prefer rail fins…
Speaking of Glass on fins. If this is a wooden lam, I also have 4.5" glass on balsa thruster sets available. My standard set up is 1" off the rail, measure up 4" then 1/8" off set for the front fins. It’s totally personal preference. The other advantage about Red-X is that if you ever play around with asymetrical tails, you can adjust one side of the red-x to assist your tail performance.