Anyways, since nobody called me out for my rant last week I thought I'd take it to the hole one more time. This week I want to share with those of you who don't already know a few little factoids about volume in board construction.
My favorite non-work related computer application is the AKU Shaper CAD program for surfboards from APS3000.com. The professional version of the program was built to work with CNC machines, but they also offer a "free download" version that I've found to be invaluable to me as a garage hack. Be warned that a few users have reported compatibility problems on their computers, but that seems to be the minority exception to the rule. I've never had a problem with it.
AKU Shaper does several things for me, but what I like most about it is that it calculates volumes for every file. In conjunction with the weight of the finished board the volume largely determines how much float you have to work with. Float isn't the magic bullet for paddling into waves but it is a crucial element.
The freebie download version of AKU Shaper comes with 4 generic templates that - if desired - can be used as the starting point for a design. Each template shows up with the various measurements and graphical representations of what those measurements look like when combined. AKU also shows the volume for each iteration, meaning that if you change a dimension AKU recalculates the volume.
The generic templates include the following:
Performance shortboard, 6-2 x 18.5 x 2-3/8 (27.26 liters)
Performance shortboard, 6-8 x 19.5 x 2-1/2 (32.27 liters)
Round Tailed Funboard, 7-6 x 21.5 x 2-3/4 (47.57 liters)
Performance Longboard, 9-0 x 22.75 x 2-3/4 (66.43 liters)
All these shapes have retail-friendly foils and rockers such as you would find on the floor at any McSurf Superstore.
Using the above info you can see that in addition to the differences in length, the volumes of these different designs are profound.
Where this information comes in handy is in enabling surfers to manage their volumes as well as their lengths when choosing a surfboard, whether it's an off-the-rack purchase or in hashing out a custom with their local shaper. Once a surfer finds a volume that results in a comfortable amount of float they can largely gerrymander their shapes and foils and thicknesses and rockers to more closely match their board with their comfort level.
For instance, at my fat-ass weight (and age) I like a volume of between 37-40 liters for many of my boards. Now normally the kids at the local McSurf Superstore would be pointing me to a 7-0 x 19.5 x 2-3/4 "shortboard" like the Channel Islands Flyer, or maybe a short funboard. And that board would be very comfortable to me in terms of float.
But I have other options, too. Depending on foils and rockers and deck profiles I can get the same volume in a 6-0 x 21 x 2-3/4 "Modfish" type shape that features a wider nose and tail (@ 12") of 14" and 16", respectively. If I wanted to go with a Simmons-style fish that uses the 22+" width with the 18" nose and 19" semi-square tail I could go even shorter, to as short as 5-0.
Now these are obviously extremes, and I daresay most people have a different idea of how much float they feel comfortable with. Maybe your personal float index is 33-35, or maybe it's 47-50, or maybe you want to stick to 60+. It's all good. The only rule I advocate is that knowledge is power. The more you know about what you need and what you want the closer you can get to picking out that magic combo and the less outside interpretation (guesswork) you need from the kid at the McSurf Superstore.
The bottom line here is that - with the exception of those people who have prior injuries - many older surfers have a lot more options with respect to board design and sizes than they realize, and most of those elements are separately negotiable.