Surf Science: Tow Technology

Tow-in expert Mike Parsons shows off his weapon of choice for an upcoming Cortez Bank mission.

Tow Technology
Measuring Today’s Big-Wave Boards

Words: Mike Fish
Photos: Taras

Do you ever wonder what propels today’s tow-in chargers across mammoth mountains of water? Well, aside from an uncanny ability to spit in the face of fear and a hefty disregard for personal safety, it’s their boards. While advances in shortboard design have slowed mostly to slight refinements, today’s tow boards are among the most progressive of surf vehicles.

The first tow boards were basically big-wave guns with straps slapped on them. But riders soon realized that all that extra volume was limiting them on the open face and they didn’t need it for paddling. So boards shrank until some started to look more like wakeboards than surfboards. “At one point, we were going more towards the water-ski philosophy,” says JC Founder and Head Shaper John Carper. “But guys didn’t like it after a while. They wanted to go back to the surfboard philosophy. There should be a lot of similarities in feel to a normal board even though it’s far from it.”

These days the lengths usually vary from 5’8” to 6’2” while the dimensions hover around 16” wide by 2 1/4” thick, depending on the spot and conditions. “Somewhere like Teahupo‘o needs a lot less rail line because you’re riding on a tiny corner on the wave face,” tow aficionado Mike Parsons says. “So you might go a little wider, smaller, and lighter there. But somewhere like Cortez Bank or Jaws, you need a little more rail because you’re projecting big arching turns.”

Also crucial to a board’s performance is its weight, which is significantly heavier than regular boards. “Anything from about ten to twenty pounds is the range,” Parsons continues. “It just depends on the waves and the winds. At Jaws, you’re up around the twenty-pound mark because of all the wind coming up the face. But at Cortez Bank, around fifteen or sixteen works better because most of the time it’s on a smooth surface.”

In big waves, a board’s weight can determine whether or not you make a vertical drop or exit a mammoth tube, so most riders customize the poundage before each session. And they do so by attaching or detaching rows of tire and dive weights in increments of five, ten, and fifteen pounds. “Depending on the spot and conditions, you’re constantly changing the weight of your board,” says Parsons. “You’re trying to put the weight between your feet so your pivot point is distributed properly on a really big wave.”

The fin configuration and construction is also fundamental to the shape’s success. The angles of the fins are towed almost straightforward and completely vertical, unlike normal boards—you don’t want water to load up on the outside of the fins to slow you down. And from there, the question is three or four fins? “Four fins are fastest because they have the least amount of drag and can hold a single line longer and higher on the face,” he says. “They feel great off the bottom and in the barrel—and can make just about any section on them. But if you get into a tight spot where you have to adjust off the top or redirect quickly, that’s where I prefer three fins. We need to find that perfect combination that will pivot well off the top and still hold a long line.”

Originally published in April, 2007 issue of Transworld SURF.