Gear Garage: Fin Friendly
Making Sense Of SUP Fin Placement and Technology
When it comes to getting into standup paddling, so much emphasis is put on the board and paddle that it's easy to overlook one of the sport's most essential elements: the fin. Picking the right fin setup--and understanding why--is one of the keys to efficient paddling and surfing. It's also the only thing you can change about your board and the way it moves through the water.
The most basic setup is the single fin. Forget its 'old school' look, the single fin actually offers many advantages that multi-fin setups lack. First and foremost is speed. With its vertical cant (the degree that the fin leans toward the rail from center) the single fin creates very little turbulence, which translates to very little drag. This is why race, touring and downwind boards feature a single fin. The fin's rake (the degree with which it sweeps back from its base) greatly alters its performance. A fin with a narrow base and more vertical rake facilitates pivoting (example: around a race buoy).
Meanwhile, a broad base with a swept-back template improves tracking in a straight line, as when downwinding. The rule of thumb for single fin placement both in and out of the surf: the further up from the tail, the looser the board will be when turning.
The most popular SUP surfing fin set up is the tri-fin, two-plus-one setup, usually defined by a deeper, double-foiled center fin, with two smaller, asymmetrically foiled fins (flat on one side) positioned on each rail. This set-up offers a mix of single and multi-fin performance: speed and neutral handling of a single with bite to hold the rail in during turns. The angle of the toe-in (the degree in which the leading edge points in toward the stringer) of the side fins, combined with the cant, causes drag and holds the board closer to the wave face, allowing for tighter, more vertical turning. All three fins are designed to work as a unit and the tried and true configuration is to line up the leading edge of the center fin with the trailing base edge of the side fins.
Fin choice is just as important when running a thruster (a triad of similarly shaped and sized fins) or four-fin (quad) set up. The main difference is defined by drag: the thruster's center trailing fin provides more stability through turns, while unimpeded water flow means the quad has greater straight-line speed and reduced pivoting capabilities.
As in every fin setup, it's all a balancing act between speed and stability, maneuverability and control. And that is what's so great about fin boxes: they offer the opportunity to experiment without buying a new board.