Large shortboard fins in a thruster setup
Sunset Cliffs, San Diego, CA
Sunset Cliffs, San Diego, CA
Large shortboard fins in a thruster setup Sunset Cliffs, San Diego, CA
Quad SUP with large and small FSI fins
2 + 1 SUP setup using two smalls and a WG2
The beginning of a vortex that creates drag.
Water flow around a typical fin tip The beginning of a vortex that creates drag.
Winglets smooth the flow and reduce drag.
Water flow around FSI’s fin tip Winglets smooth the flow and reduce drag.
2 + 1 Setup Using FSI’s WG2 in a SUP Board
FSI small fins used as sidebites in a 2 + 1 SUP setup
FSI shortboard fins in a thruster setup
FSI smalls as sidebites in a 2 + 1 setup with the WG2
Yeah, maybe everybody says that.
But we explain on this site the hows and whys of it all—the underlying science. We hope to remove the hard-to-understand mystery, folklore, and tradition behind surfboard fins so that surfers and paddlers can judge for themselves. We don’t try to be the last word on all this—we want to be part of the discussion. We encourage folks to try our fins against their favorite fins, and to join the conversation.
Fin Sciences’ fins are different. Our fins are based on solid, modern science. These aren’t your granddaddy’s fins designed in the 1960s. Our surfboard fins and SUP fins are so unique, they’re patented.
You might have seen some of the features we use in our fins, like winglets, being used elsewhere these days. If you’ve ridden an airplane recently, probably you’ve noticed winglets on the end of airplane wings. Winglets are on wings because they reduce drag—and they reduce it a lot. NASA and Boeing scientists found that winglets reduce wing drag by 20 to 30 percent. Read article. Sailors will recognize winglets as something that appear on boat keels, help wing races, and help boats perform better.
Because our fins produce a lot of hold and drive with less surface area, this means you can use a smaller fin than you usually use—smaller by about 20 to 30 percent. A smaller fin means less skin-friction drag, because every square inch you drag around creates drag, especially important when paddling—less drag means easier paddling, more speed, and longer sessions. Read more about how to pick the right size SUP fin. These features help make surfing more fun too—more drive through marginal wave sections or in marginal conditions, less stalling during cutbacks and bottom turns, easier acceleration means better wave-catching ability, and easier paddling means longer sessions.
We use other design features too. For example, we use a high-aspect ratio fin to reduce drag, and to increase lift—hold and drive. (Read more about lift, drag, hold and drive.) Some might say that a high-aspect shape will promote stalling. But we use a foil section that inhibits stalling. And we use a bulbous forefoot and a cutaway to reduce interference drag too.
The science of all this is proven. We just put the features together in fins. Winglets and the other features we use help fins turn better using less surface area for more speed and less drag. Sure, you can surf with drag. We used to fly kites way back when with rags attached to their tails to keep the other end up and into the wind. They flew. But grandpa’s kites of the 1960s aren’t anywhere near as maneuverable as modern-day kites.
Many dolphin dorsal fins look just the way they did a generation or two ago. FSI fins sure don’t look like those dolphin fins that were hand shaped by a dude in the back of his VW bus in some remote surf spot! And why did they take the center fin off a dolphin’s back and stick it on the tail of a surfboard anyway? And why do we typically use two dolphin fins—like in a thruster setup, where one dolphin fin is a double foil (symmetrical) and the other is chopped in half, with one asymmetrical fin on each side?
We didn’t just adapt an existing design, or paint graphics or a name on on existing designs. We started with a blank slate. We studied and researched advanced foil, fin, and wing design, aerodynamics, hydrodynamics, fluid dynamics, physics, and then we tested some of the most advanced foil sections available. Then we combined a bunch of other features designed to make these fins go fast and turn well.
SUP racers and SUP race-board companies are increasingly looking to naval architects to design low-drag race paddleboards—to squeeze out a couple or a few percent. In a half-hour SUP race, even a one-percent difference is 18 seconds. Fins are part of the equation of paddling fast, winning SUP races, and having fun.
First we created the Wavegrinder fin for longboards and SUPs. We’ve since designed shortboard fins too. We are working on other new SUP fins for downwind and straight-line speed too. And we have more ideas also.
You don’t have to know much about surfing, surfboard fins and standup paddleboard fins to know that most fins look like dolphin fins, and that most fins have been pretty much the same for 50 years—or at least for decades. But during that time, hydrodynamics science has evolved. Why haven’t fins?
We hope you’ll give our fins a try—even though they don’t look like your granddaddy’s fins!
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