I recently made a 6 10 x 20 x 2 1/2 bb thruster - from a 7 - 0 R clark blank i left the tail end quite thick, but really foiled out the front end. I pretty much left the rocker as it was. the board cathces waves fine - but seems to have little drive - very difficult to find the sweet spot. anyone got any ideas what i did wrong?
The first thing I’d look at are the rails. Too soft and water will wrap around causing drag. Then look at the bottom of the board from rail to rail. As a general rule, the closer to flat it is rail to rail, the more efficiently it will plane. Also, how thick are the rails? I made a longboard that had the same problem, so I skinned the bottom and reshaped the bottom only. I went from 50/50 rails to down rails, and really sharpened it up at the tail. The center went from slight belly to flat rail to rail. I increased to tail rocker a little, and now it’s much quicker and turns 100% better. I think thinning out the rails made a difference, by reducing surface area in the water, therefore reducing drag. I’m sure someone else at Swaylock’s will be able to chime in with good input for you. Doug Schuch
I’m with Doug on the bottom if it is slow… The sweet spot thing along with drive problems might be more to do with fin placement on a thick tail. If the fins were positioned based on the outline, they may not be compatible with the effects of the thicker tail (it moves the sweet spot along with the balance point). If you have plugs, try some bigger fins and see if that works.
Thanks for your input lads, really interested in lee’s observations about thicker tail, sweet spot, fin placement. How does thickness in the tail affect the balance of the board?
Thicker tail = more stability but less turning responsiveness, at least on the bopard you are describing. When you say thick, just how thick is the tail on the board in question? Drew
More weight forward increases drive. You took everything out of the front. Tape 6 ounces of lead to the nose and see the difference. I’m serious here. Try it… it works.
Just like taping a penny to the nose of a paper plane.
Exactly…
I’ll try it and feed back - sounds like an intelligent solution