Surfboard Fins – Common Questions
Do I need FCS II or Futures fins?
It depends on the boxes in your board, not the fin brand. FCS II boxes have two short slots per fin and the fin clicks in with no screws. Futures boxes are one long slot and the fin is held by a single grub screw with a fin key. The two systems are not interchangeable. Older FCS boards with two separate plugs and screws take dual-tab fins, and FCS II boxes can also take those older dual-tab fins with FCS's compatibility kit. Every board listing on our site shows which boxes it has.
Which fin system do …Lost, Firewire and Quiet Flight boards come with?
…Lost boards come through in both FCS II and Futures, so check the listing for the board you are looking at. The Firewire boards we have stocked since 2023 are Futures; 2020–22 Firewires came in FCS II or Futures. Quiet Flight boards are almost all FCS II.
What size fins should I ride?
Size by your weight. FCS: XS under 55 kg (about 120 lb), S 55–70 kg (120–155 lb), M 65–80 kg (145–175 lb), L 75–90 kg (165–200 lb), XL over 85 kg (190 lb+). Futures: XS/Grom 75–115 lb, S 105–155 lb, M 145–195 lb, L 180 lb and up. If you sit between sizes, go bigger for hold in powerful waves or on a bigger board, and smaller for a looser feel in small waves.
Thruster, quad or twin – what is the difference?
A thruster (three fins) is the all-round setup most shortboards are designed around: balanced drive, control and pivot. A quad (four fins, no center fin) is faster and holds well in hollow or bigger waves, and feels looser off the top in small surf. A twin (two fins) is the fastest and loosest, with the skatey feel fish and small-wave boards are built for; a twin + small trailer adds a little control. Boards with five boxes let you switch between thruster and quad.
What do rake and upright (pivot) fin templates mean?
Rake is how far the fin tip sweeps back. More rake gives longer, drawn-out turns with more drive and hold, which suits down-the-line speed and bigger waves. An upright or pivot template has less sweep, so it turns in a tighter radius, changes direction quicker and releases more, which suits small waves and surfing in the pocket. Futures puts this on its 1–10 Ride Number: 1–4 are Speed Control fins that feel solid and engaged in powerful waves, 7–10 are Speed Generating fins that feel springy and lively in weaker waves.
What fins do I need for a longboard or mid-length (2+1)?
Most longboards and many mid-lengths have a center fin box that takes a single fin on its own or with side bites. A common rule for a single fin is about an inch of fin per foot of board, so a 9'0 longboard rides around a 9" fin. When you add side bites for a 2+1 setup, drop the center fin to roughly 6–8". Side bites come in FCS II or Futures to match the board's side boxes.
How do I find the right fin on this page?
Use the filters at the left: Brand (FCS or Futures), SIZE for center-fin heights and SETUP for thruster, quad, twin and 2+1 sets. Every product lists the fin system it fits, and we ship nationwide with pickup at our California and Florida surf shops.
