By Aaron Checkwood
When considering the overall design of a board, the tail's crucial because it gives you the right amount of speed and control you need (control meaning basic stability). When surfing, at any given time approximately two-thirds of the surfboard is actually in the water, with the last third, or the tail, being the most crucial to the ride. There's a simple question you need to ask yourself when figuring out what works best for you: how much speed and control do I need?
Think of it this way–your tail is your speed pedal. A thin, narrow tail pushed down will slow a board down, but it'll also stabilize it. In larger waves, a narrow tail is necessary because speed is created by the power of a wave. If you look at big-wave boards, especially guns, you'll notice that they're thin pintails with less volume in back. Less area makes planting an edge easier. You're sinking, but the speed of bigger surf keeps you on the wave.
For smaller surf, a wider, thicker tail creates a larger area–therefore it planes more. What's planing? Planing is the phenomena of floating more above the water than through it, and therefore going faster. It's like extra horsepower with less control and more turning ability. Pumping, or repeatedly pushing down the larger area of the tail creates the acceleration of speeding down the line.
The following are three of the most commonly used types of tails:
The Rounded Pin–This design's basic function is to grip a wave. Pins hold power whether in larger waves or a powerful surfer in small waves. Wide or narrow, the pintail's gonna give you the most hold in a turn–it's the stiffest in terms of turning.
The Squash Tail–The added area (or rounded corner at the end) of a squash provides both volume for speed and less grip (sinking) to the wave for turning. The most commonly used tail in small to medium waves, the squash is great for turns.
The Swallowtail–The swallowtail is a combination of the control of a pintail and width of a squash tail–it's the best of both worlds. With a swallowtail, you can have the volume for speed, however, the “V” at the end of a wide tail means the wide planing surface will loosen up, making the board easier to turn.