Bat, you make good points. As for me, I’m mostly parroting what Greg Loehr taught me (fish need vee, he shaped 40,000 plus boards) And what works for me in east coast gutless waves without the speed of the pacific.
I will also point to Greg Griffin in his preference for flat bottoms.
All the best
Personally I'm always ready to learn, although I do not always like being taught. - Winston Churchill
...Hi Greg; not to disrespect but (also I told him at some point here) never ever he really 100% completely handshaped all those boards.
Anyway; a fish is way better to not have a V and not have a thruster set up; only some rocket fish would. Longest fish at 6 or 6 1 and those are for the bigger guys so for mid sized and small guys larger is 5 7 hence you do not need V cause is a very small board (mine is 5 2 )
The Fish is so skatey that if you put a V finish too slide (y) and lose hold and speed.
There are other parts you would tweak to shape a modern fish; but seems that all are very busy building old fishes with wrong rails and keel fins...
-The bottom depends deeply on the surfer s skill. If you are "plastic" flow good surfer that use a HPSB; a concave between the fins would not interfere could be good for some maneouvers.
Waves are not subtle so no subtle changes, when you put a concave should be deep if not is like not putting anything, Like a V etc.
Double concaves are in reality one of the V bottoms. There are three V bottoms (flat, convex and concave) if not are channels actually.
I use a Bonzer style and the shape is faster intrinsically.
Most of the boards that I shape have flat bottoms and in some ranges; a V bottom in some part of the last 1/3 but I use plenty of tail rocker and in some range; a kick in the tail.
I like to put thickness onto the middle of the board (all along) so the surfer can crank it up with the rear foot to carve down and go to the pocket with a powerful turn.
Lastly I have been having some trouble, due to lack of good surfers showing here so plenty of orders to the surf shop or to beginners.
I think it very much depends on the style of the surfer and the fin setup. Front footed on a thruster needs something different than rear footed on a thruster. Singles where you're letting a longer rail line do all the driving needs something different the HPSBs where you don't have the length or the straight lines in the template to drive off of.
TO ME, straights for speed and curves for control still seems like an applicable rule of thumb.
So what I have here is a basic flat bottom in the forward 2/3’d and then—-/
V in the Tailblock.
Modern “Chine” Rail. Tucked Edge below the Apex.
^^ That's how I do my bottoms on shortboards
Directed at nobody in particular.
Structurally -- concave should make the board thinner while helping to preserve stiffness.
A venturi channel (concave?) increases pressure before and after the narrow section. Water is moving faster and at lower pressure while traveling through the narrow section.
Swaylocks Surfboard Design Forum: thoughts & theories ... practical & theoretical
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