The bottom contours of your surfboard and how they are blended together, play a big role in how that board is going to perform. The idea of using different bottom contours is to produce somewhat of a controlled lift and drag effect, playing into how and why a board will interact with the wave.
Our friends at Boardcave often get asked what type of surfboard bottom works best. To keep it simple, the three main categories that your bottom contours will fall into are: Flats, Concaves and Convex’s.
All boards incorporate at least one of these, more than likely blending them with the others to help dictate how your board is intended to perform. Once you establish what kind of bottom you are looking for, you can use the Board Engine to then compare similar surfboards to find the one that suits you best.
Simply put, flats are just the flat sections of the bottom of your board. Generally, flats are fast but they do not offer much in terms of adding to performance except speed. They plain on the water, but they do not provide added lift, and they don’t contribute to directing water flow or providing leverage when performing maneuvers.
They are often blending with concaves and convexes and are placed strategically along the bottom of your board, giving you a section of your board that you can use for pure planing speed down the line.
Concaves are the areas on the bottom that rise above the rail line. Concave’s produce lift as well as laminar flow of the water under your board. They also slightly increase the overall surface area compared to a flat section, and can help get your rail to “bite” on the waves face.
The direct front to back flow of water in an Album Surfboards single concave model the Destroyer increases your speed. Next to the controlled release of water flow out the sides you get in a Polyphonic with single to double concave.
There are a number of different concaves. Single concave, double concave, tear-drop or spoon like concave (found on many nose rider longboards) to name a few. They all produce lift and direct the flow of water under your board, allowing you to sit more on top of the wave. With a nice down rail, you can have lots of control on good days, helping to keep the rail in the water.
Convex contours, on the other hand, are any part of the bottom of your board that sits lower into the water than your rail. Found on a lot of longboards, displacement hulls and sometimes hybrids, these help the the transition from rail to rail, and can provide some forgiving stability depending on the board.
Depending on the board, you may see convexes as: a smooth, rolled “belly”; hard angled Vee; or in various degrees of the two.
The rolled “belly” can be seen on a lot of longboards, and blending into some hybrid style shapes. It’s generally found around the nose and running down the length of the board until it is blended into another contour. This can help keep the rails of your nose above the water line, preventing you from pearling…which is especially handy when doing out of some turns.
Vees are usually found around the tail of any style of board, and help with control off your back foot, as well as assisting your rail to rail transition from the tail.
By understanding more about surfboard design, you can make a more informed decision about your next board.