DIY Retro Twin Fin Surf Board, Part 1: Design

As I have taken to surfing one thing has remained the same, prices on boards never seem to drop. A showroom stick can set you back upwards of a grand now, and they seem be more and more temperamental, with pressure dings and fractures happening appearing under the slightest touch. So I decided to get in touch with my inner 1950s Hawaiian and make my own board.

After reading former Surfer magazine editor Matt Warsaw's magnum opus, The History of Surfing [Chronicle Books], which covered the sport from its humble Polynesian beginnings to the current mass market/sub-culture line it tightropes now, the urge to make my own board set like a hook. It is a practice every surfer should experience at least once. After taking a blank and shaping it into rocket to sling under the arm and sprint down the beach toward the tideline, there is a sense of accomplishment, especially when dropping in on that first wave and pulling it toward the lip; it will be one of the most memorable rides of your life. But first things first, design.

Design

Perhaps the most important step in the entire process, design will dictate what the board is suited for. So there are a few things to take into account: what you surf the most (and have readily available in the quiver—don't want to double up too much); what is your home break like; and what do you think you'll want to surf in the future? Design comes down to the individual, this is, after all, a custom surfboard, so some foresight and time is needed before tracing out the board's shape.

US Blank 6'8" P - Soon to be Retro Twin Fin Surf Board

If you do not take your time on this, no matter how much time and effort you expend on the construction, if the design is off, does not suit your break, or is contrary to your personal surf style and/or physical requirements (too big/small, too much/little foam—too much/not enough buoyancy),all that work is for naught; it doesn’t matter if it is pretty, this is about function.

Living in South Florida, in the shadow of the Bahamas, where a decent swell comes in the dead of our too short winter or with a hurricane, I am mostly surfing small, wind chopped, chunky close-outs. So something that can power through the chop without slowing down is a must, which means when tinkering with design there is only one way to go: only short shorts and floral shirts need apply, I tapped into my inner Magnum P.I. and went with a Retro Twin Fin Fish.

The fish is the perfect design for South Florida. Small and responsive with enough buoyancy to keep the nose above the chop, and quick enough to drop in before the wave closes out leaving you with nothing but class four rapids. Using an US Blanks (made in the USA baby!) measuring at 6'8”P, 21 1/2” wide, I chopped the board down to (preglass measurements) 6'1” tall, the width running 14 3/4” (one foot from nose)—20” (at widest)—14 1/8” (one foot up from tail), with a deep 6” swallow tail. Cutting a solid 6” off the nose, the rocker was reduced to 3 3/8” at the nose, with the tail kicking at 2 3/16”. The thickness, after all was planed and shaped, wound up being 2 1/2”—down from 2 3/4”.

For this board I wanted to experiment with a few design features. I am taking some design cues from surf legend Tom Wegener's Seaglass Project with the bottom of the board. The Seaglass is a revival of the Alaia, Hawaii's original surfboards, with some tweeks: they have no skegs (like the Alaia), but the rails are squared and the bottom has a concave groove running through the tail making them incredible riding boards for small waves. With no fins, the board is a little loose, but the concave groove gives the board some stability while the rails suck water under, propelling it like a rocket. You have to get low on the board, and position a lot of weight on the back, but the speed and surprising control are unique and the ride is like nothing else.

Tracing out the retro Twin Fin with deep swallow tail.

For the fish, I am sticking with fins (I am no Tom Wegener), but adding the concave tail, starting a third of the way down, though not as deep as the Seaglass (only about 3/4” deep—I am loosing buoyancy but the speed will make up for it), and I am hardening the rails at the tail, giving them a sharper, more squared shape. I want to see if I can gain some speed while keeping the classic feel, shape and rideability of the fish. I am also running the fins parallel to each other, versus the slight angle of fins found on boards today. The theory is that the concave shape will add to control, the reduced drag of the parallel twins will help with speed, and the deep swallow tail will keep it loose for agility.
 

For glass, I am going with 4oz. S-glass; single layer on the bottom and doubling it up on top. I am also going with Epoxy resin, adding strength and durability to the overall board, while reducing weight from the standard polyester resin of DIY projects. To help with the glassing and epoxy/composite work, I am calling on veteran Catamaran Designer and Master Boat Builder Michael Bell of Offshore Catamarans to help with ratios, technique and any sage advice he might have to offer on hydrodynamics, buoyancy and the chemistry behind the process .

We'll see how the design tweaks work; they may be a bust, but nonetheless, it should be a fun project and I'll keep you folks updated as I move along with the Retro Twin Fin Fish. Keep it classy and enjoy the Shore Life!