Designer Curtis Hesselgrave develops new, better stabilizers on a wave of 'trial and error'

By Terry Rodgers
December 6, 2005

Fin makers historically have been among the most eccentric artisans in the surfing world.

The legendary Tom Blake, who in 1935 was the first to attach a fin to a surfboard, was a mystic loner. George Greenough, whose flexible, raked-back fins were inspired by the dorsal fins of dolphins, remains a stony recluse in the Australian outback. Fin box innovator Tom Morey, who renamed himself "Y", is a classic mad scientist.

One of the current masters of fin design, Carlsbad's Curtis Hesselgrave, has pursued this specialty with both passion and precision. If he has any loose screws, they are well hidden.

A self-taught mechanical engineer who also knows a thing or two about physics, Hesselgrave, 59, has approached fin making over the past 30 years as both an art and a science.

His favorite technique?

"Trial and error," he said. "It's a powerful sorting process to come up with a good design."

Fins are an integral part of any surfboard.

"You can't separate boards from fins," he said. "The board is a planing hull. It's skipping like a rock across a pond. Fins give you the character of how a board will ride." "My job is to provide a service to the board builders," he said. "I'm helping them with fins that allow their boards to work better."

He is a walking almanac of knowledge on how fins work.

"A surfer on a tri-fin board is using only two of the fins at any given time," he said. "When he's moving across the face of the wave, the outside fin is just along for the ride."

Raised in Nyack, N.Y., on the Hudson River, Hesselgrave briefly attended the Pratt Institute in Brooklyn before finding work as a lab assistant at Columbia University's Lamont-Doherty Earth Observatory. He spent seven months at sea with researchers who were documenting the theory of plate tectonics. By age 20, he'd been around the world.

A personal turning point came when he was befriended by Ray Hicks, a NASA aeronautical engineer, who trained Hesselgrave in the fundamentals of science. At age 22, he moved to Laguna Beach and quickly discovered surfing.

In 1971, he fell into a job working for Mike Hynson's Rainbow Surfboard Co. A year later, he was hired by Bill Bahne of Fins Unlimited, whose adjustable fin-box systems for longboards would become the industry standard.

While always hovering around the surfing industry, Hesselgrave explored some side roads, too. He spent years in the skateboarding industry as a magazine writer and promoter of the sport.

Designing the now-defunct Del Mar Skateboard Ranch helped him realize his talent for engineering.

By 1982, he was manufacturing surfboard fins at his own shop in Escondido.

At the end of the decade, he was swept up in the windsurfing craze. He designed fins that in 1990 helped sailboarder Pascal Maka set the world speed record for sail-powered craft at 43.6 knots (50.2 mph).

The fins Hesselgrave designed for windsurfing came in handy during the late 1990s, when tow-in surfers complained of having trouble turning their boards in waves over 30 feet.

Working with Hawaii's Laird Hamilton, he designed fins for a tow-in board that were slightly concave on the inside surface, a feature that increases stability at high speeds. It evolved into a four-fin board that became a breakthrough.

"This has enabled modern tow-in surfing (where surfers are towed into waves by partners on personal watercraft) to become what it has become," Hesselgrave said. "Fins were a huge part of building the bridge to that new frontier of surfing."

This fall he left Future Systems, a Huntington Beach-based fin company, to rejoin his longtime friends Bill and Bob Bahne at Fins Unlimited in Encinitas.

The company recently acquired a computer-driven milling machine that can make sophisticated fins at high volume. Hesselgrave adores it. He can design a three-dimensional fin on his laptop computer and the machine will make a precise copy.

His current experimentation is exploring how flex in fins stores and releases energy. Template, foil and flex are the three controlling factors that determine how a fin performs, he said.

"Flex is the least understood design component in all of this," he said.

Looking to the future, he envisions advanced designs that will speed up classic longboards by 20 to 30 percent.

"We're not done, not at all," he said. "Surfing is still a neolithic culture. We're still in the new stone age. We haven't reached the Bronze Age yet."