First fins to the finish: ‘Finologist’ Larry Allison paddles against the tide with fins designed to make paddleboards faster

Larry Allison at his LA Fins office in Torrance, he makes fins for surfboards, paddleboards, stand-up paddleboards and windsurfers. Photos by Kevin Cody

By Kevin Cody

Larry Allison is confident his newest fin concept will be validated at the Fifth Annual South Bay Paddle on Saturday, June 3. Approximately 100 prone paddleboarders will compete in the 15-mile race, which runs south from the Hermosa Beach pier to Torance Beach, then four miles out to sea to the R10 buoy, and back to the pier. 

The paddleboards will vary in length and shape. But all will rely on a large tail fin for stability, and direction. Except the two paddleboards Allison is preparing. Allison’s boards will not have tail fins. Instead, they will have two small fins along either rail, just forward of the traditional tail fin position.

The boards will be 14-foot Vesls, paddled by Vesl founder Mikey Roberts and a Vesl team paddler.

Surfers began experimenting with twin fins in the ‘60s. But surfboard twin fins weren’t widely accepted until the late ‘70s when Australian Mark Richards won four consecutive world titles riding twin fins.

Allison has experienced similar resistance to twin fins from paddleboarders, most of whom are surfers, and similarly tradition minded.

“They follow the pros,” Allison said during an interview at his LA Fins factory last week, in Torrance. 

“When Kelly Slater’s Channel Island ‘potato chips’ were introduced in the early ‘90s I’d ask why anyone would spend $5,000 for a surfboard. I said $5,000 because the average surfer would need a $4,000 Jet Ski to catch waves on those boards,” Allison said. Surfers struggled on the wafer-thin boards for a decade, he noted, before recognizing the importance of volume in board design.

Allison calls himself a “finologist.” Within his narrow niche, he has fought to put function ahead of fashion, and make function fashionable for five decades. His factory shelves are stacked with file boxes with over 1,000 fin templates. He estimates he has sold over one million fins.

The San Pedro native started making fins at 13, after landing a summer job at San Pedro Surf and Sport in the early ‘70s. 

“My job was sweeping up the shop and cutting out fins with a jigsaw. It was the summer job that never ended,” he said.

Hermosa Beach boardmakers Hap Jacob, Bing Copeland, and Dewey Weber were among his first customers. In the early ‘70s shaper Jeff Ho enlisted Allison to produce the flexible keel fin for Ho’s innovative Zephyr guns. Current customers include Tyler Hatzikian, Matt Calvani/Bing, Donald Takayama, and Almond Surfboards. In his early years, Allison water tested his designs by competing on the WSA tour. He still water tests his windsurfing, stand-up and prone board fins. When windsurfing became popular in the mid ‘80s, Allison’s Ninja fin commanded the market. 

“The design was based on the wings of a Canadian cargo plane I saw on a magazine cover. The wings looked like daggers. So, I called it the Ninja. It became windsurfing’s best selling fin,” Allison said.

When shaper Bill Stewart designed the Future Fins fin box system in 1992, he hired Allison to design the fins.

Stewart, Allison recalled, insisted his name not be on the fin system because he knew other surfboard shapers wouldn’t use a fin system named after a competitor.

When stand up paddling became popular around 2010, Allison tried it, and hated it.

“The boards performed horribly,” he said. ”Then I put one of my Dagger fins on my board, and fell in love with the sport,” he said.

Allison won his first SUP age group race, and the Dagger, which is similar to the Ninja, became stand-up paddling’s most copied fin.

Allison also made single fins for prone paddleboards during this period. But he was not enthusiastic about the sport until he met Mike Roberts, who founded Vesl Boards in Costa Mesa in 2018. Roberts was the rare board builder open to innovation.

In prone paddling, narrow boards are faster than wide boards. Knee paddling is faster than prone (lying down) paddling. But narrow boards roll more than wide boards, making knee paddling in bumpy water always challenging, and sometimes impossible.

Allison saw twin fins as a way to make narrow boards stable, facilitating knee paddling. He dismissed the argument that twin fins create more drag than single fins. 

“Drag is created by vertical length. My twin fins have less combined length than a traditional single fin,” he explained. He noted that twin fin surfboards are recognized as faster than single fin surfboards. 

“Why shouldn’t the same be true for paddleboards?” he asked. But he recognized a problem with the comparison.

On a surfboard, twin fins cant toward the rail to enable the board to turn quickly. But paddlers race point to point. Swerving, or yawing, adds distance. To eliminate swerving on a prone board, Allison knew his twin fins needed to be seated vertically. But unlike surfboards, whose bottoms are flat, prone board bottoms curve. So Allison designed the Pro Box, a fin box system that allows fins to be adjusted to a vertical position, regardless of the bottom curve.

When asked where he received his engineering degree, Allison answered, “The school of fish.”


Larry Allison with a Vesl paddleboard like the two he is equipping with twin fins for the Saturday (June 3) South Bay Paddle.


“Fin design is not a science. It’s more art and surprise,” he said.

Allison has countless stories about South Bay aerospace engineers asking him to build fins based on their tank tests, and computer simulations.

“They miss the fact that a fin is moving through a fluid that is subject to constant, 360 degree changes. The engineers can’t account for how many inches fore or aft of center fins needs to be, depending on the board length, and the paddler’s size and position. Or the fact the force on a surfboard fin comes from the wave, behind the fins; the force on a paddleboard fin comes from the paddler’s hands, in front of the fins,” Allison said.

Allison is confident his twin fin Vesl boards in Saturday’s South Bay Paddle will outperform  single fin boards with similarly competitive paddlers.

If not, on Monday he’ll take the boards to the world’s largest test tank, and record on video how the ocean bubbles and swirls past the two fins. If the bubbles cling to the fin, it means the fin isn’t providing sufficient resistance to reduce rolling. If that’s the case, he’ll increase the foil. If the water swirls past the fins to the tail, expect to see more twin fin paddleboards in the 2024 South Bay Paddleboard Race.

The South Bay Paddle is Saturday, June 3. The 15-mile race starts at the Hermosa Beach pier at 7:30 a.m. The three mile race starts at 8 a.m. The raffle will include a 12-foot Vesl paddleboard, a 12-foot hollow Mick Dibetta model, Nelo paddleboard, and LA Fin prone board fins.

Register at Race divisions include stock, 14-foot, and unlimited prone paddleboards (hands only). Age groups are Men (18-39), Almost Legends (40-49), Legends (50-59), Kapuna (60 and above). Women divisions are Stock, 14-foot and unlimited. The South Bay Paddle is a great training paddle for Rock 2 Rock (Sunday, July 16 from Two Harbors on Catalina Island to San Pedro). The South Bay Paddle is also a qualifying race for the Catalina Classic Paddleboard Race (Sunday, August 27, Two Harbors to the Manhattan Beach Pier). ER


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