When you change your tires, your vehicle drives a little differently, albeit the shift is hard to notice. But when you change the fin on your longboard, there’s a startling difference in a board’s functionality — especially if the type of longboard fin is far different from its predecessor.
The right fin on the right longboard on the right wave could be the easy retrofit needed to make your board (and you) perform that much better. But to know which fin you need for a certain wave and longboard, you need to understand the longboard fin types and their purpose.
Fin Terminology
Before you’re able to understand the types of fins for longboarding, you need to understand a few basic terms.
- Rake is the curvature of the fin. The more rake, the more the fin bends over itself. Fins with more rake tend to have more flex, or bendiness.
- Flex is the bendiness of the fin. When driving through a turn with a flex fin, the more flex, the more potential energy is stored up when the fin is bent, and as it comes back to center, it helps drive you forward.
- Foil is the shape of the side of the fin. Foil accounts for the thickness of the sides and how they taper off.
Longboard Fin Types
D Fin
D fins, also called “rudder” fins, were the first type of fin, modeled after a rudder on a sailboat. D fins are no longer very functional — they were originally built out of necessity so that surfers could control massively heavy 50-pound surfboards.
In older eras, boards were so heavy that these types of fins were the only ones that could hold them from sliding out. But now, with advances and lighter boards, smaller fins can handle modern longboards — even our version of meatier ones — with ease. D fins are still used, but more-so for nostalgic traditionalists that prefer a time warp to 40s-era surfing.
Hatchet Fin
These odd-looking fins have more rake at the base for better turning that a pivot fin, but there’s a square end that helps hold the board in the wave, which helps for setting up noserides. The general consensus, however, is that these fins don’t work all that well, but they’re unique and showy, and some longboarders are attached to the way they make a board perform.
Pivot Fin
Pivot fins are more vertical, straight up and down fins without a lot of rake or flex. They’re a standard for noseriders, and they work well for meatier longboards slathered in volan. Pivot fins feel more traditional but carry a hint of performance, but on the wrong board, they’ll slow you down as there’s slightly more effort and difficulty with turns.
Cutaway Fin
A cutaway fin started as a fin with a small carved-out section near the base of the fin that allows water to flow through the notch easily, letting a surfboard turn easily. Cutaways were made specifically for a 2 + 1 longboard setup as the displaced base volume loses drive, so sidebites help with propulsion and hold the board from sliding out.
Now, fin makers are seeming to leave the old notched design behind for a fin that starts small at the base. Wingnut’s cutaway by RFC is one of the newer versions available.
Flex Fin
Flex fins are typically rakier types of single fins that offer more bendiness, or “flex,” than a traditional modern longboard fin. With the bendy tip comes a setback in stability, but longboarders turn to flex fins for the loose and springy feel that makes a big surfboard come to life on a wave. In flex fins, there is less foil at the tip to make it snappy.
Note: a flex fin more describes the characteristic of the fin than the fin type itself. You could have an all-around single fin, pivot fin, or other type of fin that has less foil near the tip, thereby also making it a flex fin.
All-Around Single Fin
The truth is, most modern longboard single fins don’t fit into a named category, so we’re going to put them into the all-around fins box. But though the range of general single fins is capacious, they fall between the not-quite-a-pivot-fin and not-quite-a-flex-fin territory.
The most popular, well-performing and endlessly copied all-around single fin is the Greenough 4A, developed by innovator and oddball George Greenough. Greenough’s fin legacy lives on in True Ames, which sells a number of his models after working directly with the tinkerer.
More all-around longboard fins can be found with nearly any large fin distributor, like Rainbow Fin Co’s Azul longboard fin or FCS and Kelia Moniz’s collaboration for her name-brand longboard fin (which looks oh so very much like a Greenough). Don’t miss Yater’s wood single fin, sold by FCS.
What Size Fin Do I Need For My Board?
Fin types come with personal preference, but in general, riding a single-fin, traditional longboard calls for an inch of fin for every foot of board, and most surfers like to round up slightly.
A 2+1 setup needs a smaller center or cutaway fin, typically in the 7-8.5″ range.
Where Should I Put My Fin?
Where your fin sits on your longboard will affect your drive and ability to turn or noseride.
The closer to the tail a fin is, the more hold it will give you. The further up in the fin box, the looser the board will feel, which could be better for turning on certain days or could mean a face full of sand. A lot of longboarders like to place their fins dead center and leave it up to chance — but, it certainly depends on if your shaper put the fin box in the right spot.