Ever been stuck in the middle of one of those fervent discussions about boards? You know the one; the chat that you lost track of five minutes previously and are now just nodding along hoping nobody asks your opinion. Words like ‘foil’, ‘double concave’ and ‘squash tail’ fly past your struggling cerebellum in a whirl and you really wish you actually understood a little bit about that artfully crafted chunk of foam, resin and love that you call your board.
Well, dear Slide reader, help is at hand. Come with us on a little voyage of discovery through the lexicon of board shape terminology, concepts and the like. In no time at all you’ll be able to hold your own, eloquently defending your choice of ‘reverse vee’.
No, not someone that likes AC/DC. Rocker is probably the most fundamental board design concept. A board’s rocker is simply described as ‘the boards bottom curve, from nose to tail as viewed side on’. The rocker affects the flow of water under your board, simple as that. Not considered how the rocker affects your board? Well, consider this: if a board has a flatter rocker it means less resistance, so the board will be fast, the downside is a flat rocker reduces manoeuvrability. Conversely, pronounced rocker will mean greater manoeuvrability but reduced speed. The balancing act between speed and manoeuvrability is one of the ongoing mysteries of board shaping. To illustrate this in real terms a flat-rockered board, like a fish, is good for weak waves as it planes easily across slow sections, but isn’t to happy doing big reo’s. A high-performance competition blade like Slater et al ride will bog in slow waves but is happy being forced though uber-tight arcs in the pocket. As a normal surfer you need to find a happy medium in between.
A board that has speed and glide but can still do turns is the Holy Grail. Your choice of bottom shape also affects the rocker, but we’ll come to that in a minute. Rocker used to be a nightmare for shapers to nail but with the advent of computer shaping the curves are getting consistent. Bottom Shape-
This is probably the most subtle design feature, being able to spot it in a board shows a depth of knowledge guaranteed to win you friends. So what’s it all about? What the heck are ‘concave’, ‘vee’ and the mysterious ‘reverse vee’? The bottom shape occurs in the rail-to-rail cross section, so it’s tied in closely with the rocker, to see it simply get a board and hold a straight object across the board. If you look down the board you will see the bottom is either concave (meaning the stringer is lower than the rails) or has vee (meaning the stringer will be slightly higher than the rails). They are not mutually exclusive and boards can use a combination of both. From a hydrodynamic point of view concave funnels water toward the tail giving a board more speed (due to sanding out the concave the rocker is in effect flattened slightly, whilst the rails retain the original rocker shape) but water doesn’t release from the rails too well. Vee is the opposite, water releases easily from the rails as the vee encourages the water flow in that direction, so the board goes on a rail easily.
Trends change but at the moment many boards feature a single to double concave, being a single concave thru the middle of the board splitting to double through the fins. Or reverse vee to double concave, reverse vee is confusingly named, the ‘reverse’ means the vee is reversed in position on the board so instead of being at the tail is between your feet, it does not mean the vee is indented as many people think.
Every top shaper has a different opinion on what works best and it’s probably best to let them get on with it when ordering a board. As it is, in fact, rocket science… Outline-
The outline or template is another one of the myriad variables in board design. The template curve was traditionally drawn on a blank before being roughly sawn out, then sanded to an approximation, both halves of the board were rarely exactly the same, these days with computer pre-shape blanks the outline is more standardised. It’s all about curves and flats again, a curvy outline will turn well straighter outlines will go faster. Three measurements are normally made the midpoint, one 12-inches from the nose and one 12-inches from the tail. Add or take an inch at to any of these measurements and the difference in shape and board volume is huge. As surfing has progressed the outlines have changed, earlier boards had more volume in the front, as surfing off the front foot was the done thing. As performance surfing and surfing off the back foot have evolved the volume has shifted backwards. Small wave boards, guns all have different outlines depending on the need for speed or manoeuvrability.
Of course the tail shape is the keystone in the outline, having a major effect on how a board works. Different variants either preserve tail volume (square/round/squash) giving a board planing area to turn off and allowing for easier take offs or reduce volume (pin tails) giving more functional rail length and a better fit in the tube. Swallow tails, or double pins as some describe them; combine both, giving the rail length and a wide planning area.
Different tails work on different boards for different waves. For the normal UK surfer the squash has become the standard, whilst swallowtails are popular on fishes and retro boards and the pin holds onto its favoured status for bigger wave boards.
So as you can see, it’s complicated. Read this, digest and go look at your board, figure out what it’s got and feel better next time ‘that’ conversation starts…
That’s your lot, next time we’ll look at foil, rails and fins the other components in the magical mystery that is surfboard design.