Terminal Velocity: How big is too big?

We have all watched massive Jaws, in awe of the surfers who claw their way into cavernous walls of water. Whenever I see surfers pushing the limits of board surfing I am pulled back into the limits of our own persuasion.

What waves are bodysurfable?

 

When we are considering what waves are makeable we need to define some terms to guide our quest. One important distinction is to establish what it means to “make” a wave. While swimming with massive waves is a feat unto itself, for the purposes of our research we will say that “making a wave” involves a rider maintaining control of their body from the paddle, through the drop and on the wave face.

There are a whole host of factors involved in making large waves. Generating enough momentum to “get into” the wave is the first to come to mind. Fitness and swim training can only get a person to a certain point. Just as there are limits to the speed a surfer can paddle, so too are there limits on the maximum speed a bodysurfer can swim. There are several groups of bodysurfers experimenting with tow-in bodysurfing with mixed results. Getting dropped by the ski does not solve the entire problem. This problem with “speed” is most directly expressed through the terms of Terminal Velocity.

Terminal Velocity is the point at which an object is moving so fast that the drag (either of air or water) causes it to stop accelerating. If you imagine a skydiver jumping from an airplane, you can imagine as he or she jumps, they will immediately begin accelerating due to the force of gravity. As their falling speed increases the wind resistance also increases. There will be a moment during the freefall when the force of gravity is matched by the wind resistance reaching an equilibrium. At this moment, the skydiver’s velocity levels off and they will continue to travel at that speed with all other variables remaining equal. They have reached their Terminal Velocity.

Water is about 1000 times more resistant than air. This tells us that our maximum stable speed through water is much slower. There are many ways by which the best bodysurfers limit their resistance/drag in the water and therefore maximize their terminal velocity. The human body is not a surfboard. All the designs that make a surfboard fast in the water; smooth surface, tight rigid frame, sharp rails, are all missing from the human evolutionary design of the body. We do our best to mimic these designs, reaching with arms and legs, flexing our bodies, and some even wear slick speedsuits.

As our bodies move faster through the water, the buoyancy force pushes our bodies out of the water. Bodysurfers have been known to skip down the face of a large wave because the surface of their body was “grabbed” by the surface of the ocean. If you haven’t personally witnessed this you can imagine a bodysurfer being dragged behind a jetski. At a certain speed that rider will begin bouncing out of the water and the “pull” on the body becomes greater because it is matching the riders’ velocity through the water.

So, how big is too big? There are teams of guys pushing this envelope week after week. We hear whispers of Mavericks or Jaws from time to time. But in all this searching we know that the best way to navigate the tirade of obstacles is timing. Catching the right wave at the right time. The shape of the next big bodysurfing wave will be the true hero of the equation. The wave has to be steep enough for the bodysurfer to maintain speed without pushing beyond his or her terminal velocity in the process. As we watch bodysurfing evolve with the next generation of wave riders we’ll keep our eyes on the horizon and hope that you are a little more prepared for the challenge.