Mt. Maunganui, New Zealand:: Assault Boardriders has just finished buoyancy testing their store inventory of surfboards. SBT (http://www.surfboardbuoyancytesting.com/) is stoked to have Assault as their exclusive license at the Mount. Owner Glenn Bright and board buyer Cale Tolley quickly saw the value of having the buoyancy marked on their boards. The information makes it easy to compare boards of similar shape regardless of the construction and together with SBT’s Buoyancy Chart a surfer can select a board suited to their body weight and surfing ability. Successive board’s buoyancy can be adjusted + or – based on your preference and make it easier to dial in a board that works for you. Glenn: “I like to be innovative and try new things in my shop. I think given the variety of boards on the market today it is time for us to provide this sort of information to our customers.” Cale: “I’d come to a point with my own surfing where I was confused with all the board choices. Now I have a point of reference for my next board”
We did this floatation rating back in the 80’s on sailboards. I’m wondering if you are using the mathematical equation for figuring litres, or if you have a displacement tank to calculate floatation.
I think displacement would be far more accurate due to the inherent difference of EPS and PU cores. A 1.0 lb EPS should float about 62 lbs. per cubic foot whereas most PE boards of the same dimensions would be far less floaty, largely in part due to being a fixed cell foam relying on cell walls to resist crushing.
Still, credit to you for establishing a foundation to work from indicating that you are an energetic retailer that ultimately cares for the consumer.
You’re right about volume not being a accurate way to calculate buoyancy given the different blanks being used today. It is also very difficult to measure volume unless you do a displacement test. Unfortunately two board of exactly the same volume won’t necessarily have the same buoyancy. Computer pre-shapes give a volume number but that is before the board is sanded and finished. We use a testing tank to submerge the board and measure the buoyant force that the board produces. This method makes it possible to compare any board construction to another. If you look at our Surfboard Buoyancy Data on our website ( http://www.surfboardbuoyancytesting.com/surfboarddata.html ) you can see that boards of similar dimensions ( volume) can vary quite a lot (10% or more). From my experience that is significant and can be felt by the average surfer.
Yes. 10% is a large number when it comes to surfboards. Experienced surfers complain if a board is 1/16" to 1/8" too thick or thin in specific areas (or overall) on the board.
Although it would be very difficult to quantify, bouyancy can have a direct relationship with planing. The ability for a surfboard to pop up onto a plane, or to achieve a degree of pre-planing speed is significant partcularly in terms of catching the wave, and trying to position one’s self while jockeying into takeoff position in particular wave conditions.
Individual preference is also to be considered: an experienced surfer may actually desire a board that has less bouyancy for a particular kind of wave that is extreme whereas a beginner or intermediate (or expert riding a soft wave) would be keen on a ‘floater’ for low energy situations.
I’ll take a look at your table.
Props to you for undertaking such a task…could make for a lot of ‘happy chappies’!