The Right Coast

August 29, 2004
Surf Science
By Tom Smith

Shocking to me is that this seems to be almost the only, and apparently the leading, research paper on the hydrodynamics of surfing, at least as far as I can tell from Google. It's 30 years old! Have there really been no advances in the theory of surfing in all that time?

I tend to think many improvements could be made in surfboards to make it easier to learn how to surf. I'll let you guess why I would think so. In the last ten years, there have been enormous improvements in snow ski design, making skiing much easier and more fun. Ski design, it seems to me, stagnated for a long time before it really took off in the '90's. Is surfing due for a similar technological revolution?

I'm not really sure. I don't yet understand what's going on with surfing well enough to tell. It may be that surfing is just planing on water, and there's only so much that can be done with a plane. On the other hand, I wonder if more sophisticated designs, of the sort one sees in speedboats, kayaks, and sailboats, for instance, might be applicable to surfboards.

Here are some wild ideas. Surfbboards are flat, giving them high initial stability, but very low secondary stability (or whatever you call it), so that one tipped, they tend to keep tipping. A U shaped hull is much more stable. Less likely to plane, though and harder to turn. Maybe big fins would make it easier to turn. This would look like a kayak you stood on to surf.

Or, what about a big channel down the middle of the board, like a tunnel boat? (I know some boards now are concave on the bottom) Would the decreased drag increase the speed of the board? Would there be a lift effect? What would the effect on turning be?

How about a catamaran surfboard? Think long, slender sponsons with fins. Could such a barge be made to turn? What if the sponsons had significant rocker (that bannana shape) and even some side cut to their shape, like slalom skis? That would increase drag, but would it make them easier to turn? Could sponsons be designed so that they planed readily?

But this is all wrong. Maybe it's all just planing, so all you can do it make subtle variations to an essentially flat surface.