Quad Fins

Four fins — two larger fronts, two smaller rears — sit near the rails with an open channel down the center. Water flows freely through the middle, generating speed like a twin, while the rear fins add the hold and control that twins lack. Unlike twins, quads let you push harder into critical sections without sliding out.

The relationship between front and rear fins matters. Larger rears add drive and stability (more thruster-like feel). Smaller rears keep the board loose and fast (more twin-like feel). Fin placement is extremely sensitive — wider placement adds stability; tighter placement increases responsiveness. As Swaylocks debates endlessly: "if you carve you appreciate a thruster and if you skate around you probably prefer a quad."

Modern quad design uses staggered fin sizes (larger fronts, smaller rears) rather than four identical fins. Quads require less pumping to generate speed, making them ideal for hollow waves, bowly beach breaks, and bigger surf where the wave provides the energy. Many pro big-wave surfers ride quads at Pipeline and Teahupo'o.