I reacently saw a board with golf ball like dimples on the planing area these apparently give an effect (similar to a golf ball) of traping water for speed and lift…Does anyone know of this and perhapes the dynamics.
from what i understand, those dimples have a similar effect to concaves but concaves are better and more efficient
they must be a blast to sand…
Check the archives, there have been some discussions on the topic in the past. regards, Håvard
DIMPLES!!!Man, they bring back memories.I rode nothing but “dimple bottoms” for like 2-3 years back in like 89-90. I saw one at surf expo and thought it was the hottest thing…Mickey McCarthy used to shape 'em and I helped with the dimple-cutting. I made this cheesey rig from a round bedknob with 40 grit glued on the end of it,stuck it in a drill…Looking back, it was definately too much work glassing and sanding those things, and they were inherently weak and prone to leaks around the dimples.Every now and then though,when you got a driving speed section and were speed-pumping down the line,the tail would hover or float like a hydro-foil. It was the freakiest feeling. Our version sucked compared to the elongated egg-shaped dimples the Willis Bros. were doing.They had this cool router-jig to cut them in with, and they looked easier to laminate,cause the dimples went more linear with the shape,allowing the glass to lay down better. I think they called them Phasers or spiral bottoms or something.Anyway,I guess the whole idea is the theory about water turbulence causing water molecules to glide over each other or something;who knows. I’m just glad I ain’t glassing those things anymore,although with a fin system they might be a little bit easier now.
Dimples on aircraft wings are used to reduce parasitic drag (fricton). They increase the air flow over the wing. Air/water…same difference. Less friction means more speed for the same amount of energy.
dimples are used to induce turbulence and affect separation. You DO NOT want separation in surfing except at a few specific locations: your trailing rails and the back edge of your fin. If flow separates from the fin, the rest of that side of the fin isn’t doing any work - can you say spin out? Know too that any time you want water to change direction, it costs energy… be it flow across dimples, around a fin, entry rocker… I don’t believe in 'em myself.
Yeah, I pretty much agree , they’re not really worth having on a surfboard. But on golfballs…To tell you the truth, some of my favorite shortboards ever were totally flat bottoms-no vee, no concaves. In fact,I’ve never been a big believer in all the concave hoopla. Most guys couldn’t tell ya what they’re bottom was doing…it’s all marketing hype!
My longboards noseride the same without concaves. In fact one that i made with belly on the nose worked the best. Just my .02 cents. Austin S.
Yea, I’ve had longboards with double concave bottoms,and longboards with rolled vee and you know what? I can do the same crap on both of 'em. I don’t even specify which I want anymore from my shaper, I just say whatever you feel like. I do want my nose concave though, it’s a mental thing.