Bottom Shapes

Hi to all.

Just chasing some opinions on the best bottom shape configuration compromise for a given range of conditions and a particular surfer.

Waves: Nothing under 3’ (chest high). Nothing over 8’ (double overhead). Only clean and offshore conditions will be surfed. Waves to be surfed are always powerful to very powerful, but wave shape varies from hollow reef and beachbreaks, to long down the line “fatter” waves (Bells, etc).

Surfer: Larger than average (taller and heavier) and far from nimble - not unlike myself really. Boards are normally around 20" wide, between 6’8" to 7’0" long and 2 3/4" to 3" thick.

What sort of rocker and bottom shape (some sort of approximate dimensions for these variables would be nice too please) would anyone recommend for one board to best handle this range of conditions and surfer.

Many thanks in advance for your advice.

Cheers

Rohan

Traditional power surfer, the flat to V, disappearing out the tail.

For a quicker responce, a full single concave, flowed thru the tail.

Both smoother than flat across bottoms, first allows longer delay for more weight transfer on powerful turns, the other flickier, quicker, edgier, but just as smooth.

Hey RDM,

the best utility will be gained using the tried-and-tested single-to-double concave. This provides quickness to plane, great drive, and will hold in fairliy extreme conditions.

A couple of thoughts:

the “single concave” aspect actually runs the full length along the bottom (fairly constant) and extends rail-to-rail. The depth of the concave ranges but a good moderate bottom will be about 1/8 inch (3mm) on average and maxes out just ahead of the front fins (maybe an extra 1mm deeper) then (important) quickly evacuates out the back. That is, the maximum depth transitions quickly to flat in the last couple of inches in the tail.

the “double concave” aspect does not run full length, it is just around the fin area. Testing has shown this to be what dictates the “feel” of the board, how the doubles start, max out, and end. A good start is to just make subtle doubles (0.5mm each) and max them out about mid-fin on the front fins. You could look at these doubles as just a widening of the single as it passes through the fins.

“rocker” is so hard to describe without gauges/templates etc. Tip numbers are not enough. Generally, the smoother the better. With this said, accelerated curves are essential especially at the tail. Adding 4mm of tail kick in the last 8 or so inches (metric/imperial are both on my ruler!) will free up the effects of the stiffening concaves and should coincide with your effort to “evacuate” water flow out the back.

There are as many variations to this theme as there are people shaping. This is just something that I found to work quite well.

HTH

I like them smooth . So , obviously, did Bunker Spreckels…

So, Ben… The “rubber love” key guard workin’ out for ya then… Ha! Smooth… and round.

You sound like you are the same size as me. I ride 6’10 to 7’2 x20 x 2&3/4. as a hort board mals are a diferernt story. I like concaves for the livelyness. single to doubl in my 6’10 for beacheis and doubles in 7’0 for speed and drive on reefs and points. the 7’2 is all together different and I have prattled on about it for years, still a favorite in some juice. tail shape is a significant factor as I feel the single to double goes better with the wider tails ( swallow and squash / rounded square) and the double goes better with pins and round pins. rocker for vicco waves are a lot flatter . hope I have helped.

I thought you liked them big ben?

Rear rocker in the 2.375 to 2.6 range. Front rocker closer to 5-5.5 inches.

Bottom config and rail will depend a lot on what kind of surfer you are. If you go rail-to-rail and gouge and turn as hard as possible and want to turn harder, then a concave/hard rail combo will suit you well (max depth 1/8" to 3/16" under front foot, flattening fore and aft). If you want stability and draw turns out more, go with the flow instead of slashing across it, you may find Vee (up to 3/16", peaking in front of the fins) and down but not so hard rails more to your liking.

I’m assuming this is for thruster fins, too…that can change everything.

Thanks guys,

All great info and very much appreciated. Aforementioned surfer is a more of a “cruiser”/positional surfer than a “high performance”/power surfer. Fin setup (single,twin,quad or thruster) is also up for grabs I guess, but I fear that introducing that into the equation may lead to thread spiraling out of control with possibilities. I guess the whole package though should really be dealt with in one hit. Let me re-ask the question then.

What would anyone recommend as a board that comes close to being a “magic bullet” for the given conditions and surfer type.

Thanks again for all of your help.

Cheers

Rohan

Via KP I offer the following:7’4", 15 5/8 X 21 1/8 X 13 1/2, 3" thick single fin, round or rounded square. About 4" nose rocker and 1.5 to 2 inches of tail lift. Pinch the rails, maybe 1/2 inch hull just forward of center. 9.5 Liddle flex up about 12 3/4 inches up from the tail block.

High line driver or bank and carve. Won’t slash about but will buckle your knees with g’s…

what about a Grant Miller “waterskate” design…

clean and simple do it all kind of board…

I love that design a real stubb-vector mentality

low entry simple vee rounded rails and continous curve rounded pin

I thought you had one Rohan?

Quote:

THE WATERSKATE A BOARD SO CHUNKY…BUT YOU CAN STILL CARVE ON IT…

6’6" x 20 1/2" x 2 5/8"

Bottom: Roll-concave-Vee

Rail: Mid boxy

Quote:

Compared to other boards, Waterskates have a lot less rocker. Now, in isolation, this would create a very fast but stiff surfboard. However, when combined with continuous outline curve we get the speed/drive benefits plus looseness.

Hi Oneula,

I do indeed have a “Waterskate”. But it’s a bit “gunnier” than the standard one Grant makes. Thanks for your suggestion. I do have a friend who’s got a standard one that I could template and have a stab at making a copy of. I’m looking for my next project and I’m not really sure what i want to do. Something that is a little different from what I already have but is still suitable for the waves I want to surf.

Cheers

Rohan

Thanks Lee. Your suggestion is much appreciated and duly noted.

Cheers

Rohan

“…continuous outline curve…” This one has always confused me - what board doesn’t have a continuous outline curve?

I haven’t read much on chine and strake bottoms, but I rode one, and it was a good way to have a wide deck for paddle speed, yet w/the 18" bottom and strake-chine combo - it went rail to rail w/ease.

Thanks for the time - keep up the fine work, Taylor

Hi TaylorO,

I assume when they talk about a “continuous” outline curve they probably mean no “reversal” of curve - flyers, etc. Continuity of a curve in its truest sense is the next step up (derivative) from tangency. It is the rate of change of the tangency in other words - a constantly “accelerating” curve. This is probably what they are hinting at even if it isn’t strictly correct or true.

Cheers

Rohan