With all the focus on volume over the last few years, it’s important to remember that whilst volume offers some guidance as to sizing and dimensions, it is not the whole story, merely another factor to be taken into consideration. Too many times I see surfers focus more or less entirely on their volume, and in doing so ignoring many of the other critical factors that play a role in surfboard design (not limited to dimensions).
Which brings us to our topic for this Shaper’s DNA discussion – the area of a surfboard and the lift it generates. As always when discussing a singular factor in surfboard design, it’s worth remembering that all the factors work in unison with each other, so whilst you can isolate what a particular board attribute does, others may give similar effects, and you need to look at them all holistically.
So the statement that your surfboard area (think plan shape to a degree, but more importantly the wetted area when you surf) has a direct relationship to the lift it provides is entirely true. Sure, a well placed concave bottom will give you lift off the rail as well, but today we’re focussing on area. Area is something you’ll very rarely hear thrown around as an important factor, yet it’s a critical one when ordering boards for your conditions, and it’s one that any experienced shaper and designer will be considering when designing a board.
Area is far more important than volume in fact when we get down to the nitty gritty, particularly when designing small wave boards.
Whether in aerodynamics or hydrodynamics, lift is the force perpendicular to the movement of the fluid (air or water respectively). In its simplest terms, lift is directly related to surface area. Double the area you double the lift. Don’t believe me? Ask NASA.
That’s why shaping your usual shortboard a half inch thicker to grovel in is not going to be as effective as riding a board with yes, more volume, but far more importantly more surface area. Take our CabSav model for example, the ultimate groveller. You may see an experienced surfer surf a CabSav in tiny surf, at just slightly more volume than their standard shortboard, and yet get a noticeable amount of grovel pizzaz going in weak, small and mushy surf. The far greater wetted surface area is creating more lift (and of course the seamless blend of foil, rocker and rail line help too! see above…). But the area is a big factor.
Now when you get into the finer intricacies of lift, and take a detailed look at it, there are other factors that come into play. For example, the density of the fluid (water in our case, and yes, some ocean locations have denser water that others) and the relative velocity of the fluid across the surface. In the case of relative velocity, here’s where it gets tricky in surfing. Not only does the surf create and have his own speed across the water, but the wave shape will determine relative fluid velocity as well. It’s why a Hawaii semi gun will have a lower surface area on a rounded pin tail to cope with relative fluid velocity (think power and speed of wave, speed of surfer across the wave) and a small wave utility board will have a wider tail measurement and tail block width.
This variability is why at this stage I haven’t seen an “AREA & LIFT” calculator, (but area is something available on certain CAD programs mind you, and there are designers and manufacturers looking at this in detail). It’s a complex consideration where experience plays a big part. Saying that, I still don’t believe a simple volume calculator is in any way an intelligent, singular consideration.
Most experienced surfers will have a naturally developed intuition and understanding of lift and area, purely by riding many different conditions and boards over the years. And trust me, your shaper probably does too, far more than you know.
So please, consider your usual volume you ride as a guidepost, but open your mind to the realm of other far more important factors in making you the perfect board and increasing your wave count.