To: tom@daumtooling.com

What do you think of the new (or so they say) vector fins by future. I read about them in one of the new rags out there. They are foiled on both sides with it looked like a curve in them that kind of matched the curve of the planeshape in the tail (in other words, if you looked at the fin from above, the base is not straight but is curved or arched, with the apex of the curve facing the rail). They claim greater control and drive, and that current fin designs are stone age technology. Is RedX doing anything like this? Any validity in this new design, from your perspective?

Here is a link to the article (in the mag itself, they have a diagram of the principle). http://www.surfermag.com/currentissue/sling/

Here is a link to the article (in the mag itself, they have a diagram of > the principle). Mike, I have not seen these fins first hand. But, according to their discription and flow diagrams, I have my reservations. The diagram that was presented showed the flow of water running parallel to the fin foil. When in reality there are numerous angles of attack that a fin foil is affected by. However, on average the angle of attack is actually going to be parallel to the stringer and askew to the foiled side of the fin. If you consider their diagram with the flow indicated in that direction you will find that the concavity of the inside surface would just provide more area of turbulence. When producing an injection molded fin, it is actually easier to produce a fin with concavity on the inside surface. In the trade we call it sink & twist. As far as having a foiled intertior leading edge, we have produced our tow in board fins with a 20/80 leading edge foil. The way a wing works is water or air flows faster long the flat surface and slower around the curved surface. The curved surface affects the direction of lift. On side fins the curved surface is toward the rail. So, the direction of lift will pull more rail into the water. At the velocities tow boards are traveling 100% foiled leading edges pull the rail into the water to the point that they are hard to turn. By breaking the edge it allows some of the water that would normally flow over the foiled, outside surface and redirect it towards the flat inside surface. Thus nulifying a percentage of the lift. So, if you feel your fins are engaging too much you may want to sand an inside radius on the leading edge of your fins. But, from the experimenting I’ve done I have not noticed a measurable difference in paddle in conditions.

Thanks, I thought it sounded too good to be true.

Thanks, I thought it sounded too good to be true. …I have to agree with Tom on this one,I’ve done some experimenting with cupped concaves,and twist in fins ,and found that there is more deficits than gains to the designs. …Also by eliminating flat insides(double foiling side fins) you reduce the vaccume needed to reduce inboard turbulence.Herb

I’ve been tempted to post this but fear of ridicule, torment and abuse prevented me from doing so. The asymmetrical concept has been applied to templates (See Channel Islands website for a recent version) and Peter Drouyn had a weird two fin concept that actually made sense to me - with a traditional looking almost longboard style fin near the stringer and a smaller more modern fin on the other side of the stringer but placed closer to the rail. For a definite special purpose board (say Rincon) how about an asymmetrical forward fin setup (say the inboard fin farther up than the outboard fin) and combine that with a flat outboard/curved inboard foil on the trailing fin. I’m thinking this would give a lot of drive on the bottom turns and some snappy off the tops and cutbacks???