Longboard single fins come in many shapes and sizes. Understanding the three main elements of fin design—base width, rake, and uprightness—is crucial for choosing the right fin for your board and surfing style.
Key Takeaways & Tips
Fin Anatomy
The base width gives you drive and speed. The uprightness (less rake) gives you better pivot. The sweep or rake (more swept back) gives you more control and helps hold carves and turns longer.
Fin Sizing Rule
A simple rule of thumb for single-fin longboards is to use approximately one inch per foot of board (e.g., a 9-foot board uses a 9-inch fin). For a 2+1 setup, you can typically go 2–3 inches smaller on the center fin.
Fin Box Position
The US fin box allows you to adjust the fin position. Moving the fin to the front of the box loosens the board, making it more pivoty. Moving it to the back of the box gives you more control and grip, which is ideal for bigger waves.
Pivot Fin
The pivot fin is upright and wide-based. It caters to traditional logging, noseriding, and trimming, as it’s designed to set a strong edge and provide a strong pivot as opposed to long, carving arcs.
Flex Fin
A flex fin has a very thin tip and a swept-back outline. It is used for carving off the rail and loads up when turning, giving a “squirt” of extra drive. Ideal for mid-length boards and boards with V-bottom contours (hulls).
Common Mistakes to Avoid
Not Experimenting
Failing to experiment with the fin position in the US box. You can easily adjust the fin halfway through a session to find the “happy ground” spot that offers the best balance of looseness and control for you.