The theory behind asymmetrical surfboards

December 22, 2010 | Surfing

Asymmetrical surfboards: do they really work?

Kelly Slater has been testing asymmetrical surfboards, shaped by Channel Islands. Some say it works, some say it is another way of marketing surfboards. In the last days, Roy Stewart, from Olo Surfer, has strongly criticized the theory behind Channel Islands' new revolutionary product.

"The claim is that moving the stringer will change the axis of rotation of the surfboard. This is incorrect, as the axis of rotation is determined by the surfboard's area distribution and the position of the rider's feet, not by the stringer position", says Roy Stewart in his website.

The avant-garde wooden surfboard shaper says the above diagram explains the surfboard will rotate around the stringer position. "It will not. Leverage cannot be increased by moving the stringer position".

Stewart believes the CI idea do not reflect the true knowledge of surfboard flex and hydrodynamics and calls it a "Myth Making Marketing Machine". Have your say. Send your ideas and opinions to editor[at] We'll add it here below.

Adam Weller:

Definitely not an expert on physics or hydrodynamics but:
Although you might not be able to increase leverage by moving the stringer it would seem to me that moving the stringer would increase the stiffness of the new (lower volume) side of the board. Further that this new stiffness could translate into increased responsiveness and power on that new lower volume side (which I'm assuming is intended to be the rider's heel-side).

Am I being too gullible or optimistic?

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