Well, I’ve heart about sanded finish bottoms, concaves,gloss and acrylics. Also some comparisons to golf balls. BUT has anyone tried to do a board with dimples all over the bottom like a golf ball ? Is this just crazy ? Or what. I don’t know what size dimples or spacing but it seems to me that it might work good for lift and speed … Pain to glass thou… Aloha…
the Willis brothers back in the 80s here on the north shore shaped dimples on the bottom of their boards. Johnny boy used to ride them. Dont know if or how they worked but I heard they were a bitch to glass.
The “dimple-effect” works best on non-streamlines objects (round) moving through air and perhaps water. Like a golfball. On surfboards it will disrupt laminar (smooth) flow of water early (=bad); increase surface area (=bad); and “be a bitch to glass.” Would a golfball move faster underwater than a smooth ball of equal size and mass? The speed most believe gained from sanded bottoms is probably due to surface tension rather than a “golfball effect” of energizing the laminar flow in order to prolong it. Sanded boards are faster to get to customers and faster to get dirty. In the 70’s some more inventive designers created riblet or micro-channeled bottoms. In the mid to late 80’s some Florida manufacturers added large dimples on the bottom of some boards. Looked like a cross between a large pressure ding and a channel to nowhere. Perhaps Greg Loehr know more about these experiments. -Rob Olliges ps. You could take a hammer to an old board and put in a lot of “dimples” and see how that works.
Don’t forget that the dimples also help to grab the passing fluid - with a golfball you want spin, it gives more lift. Surfboards don’t spin, note that you don’t see dimples on airplane wings. Some wings will use a tripline to induce turbulance, but that is a very specialized design - and lets not forget that water and air have very different affects on an immersed body.