Surfboard concaves: Single, double, V, flat... what they are and how they change the feel

What are Surfboard Concaves? I can hear you thinking to yourself. Turn your surfboard over, or the one in the surf shop, and you may notice a smooth subtle contour, or contours, carved into the bottom of the board. These contours will run from the nose (the front of the surfboard) down towards the back end of the surfboard. These contours are called concaves and can vary dramatically in length.

Concaves on surfboards are used to channel the direction of the water flow under the surfboard towards the fins. They also allow air to get under the surfboard when you are surfing on a wave. (A bit like an aquaplane.) Concaves on your surfboard will increase both its sensitivity and speed. Occasionally, this can be too much of a good thing, and we will talk about the solution to that problem further down the page.

These concaves can be just the one simple line to complex channels and contours in various shapes. On a contemporary shortboard design, the concaves can often start about 12 inches from the nose and run the full length of the bottom of the surfboard to finish in the middle of the tail. Different concaves can dramatically alter the feel and response of your surfboard. There are several different concave options available to surfers.

Single Concave. As you may have guessed from the name, this design features just the one concave running down the middle of the surfboard from the nose towards the tail. The single concave is best suited for big clean waves. This means that this design is not great if you are looking for an all-rounder type of surfboard. The single concave will enable tighter turns on the waves and is best suited to the surfer who isn't carrying any extra pounds.

Double Concave. (Also Known as Single to Double.) This design is possibly the most popular of the concave options at the moment. Again, the name is fairly self explanatory. Your surfboard will start with one contour up near the front and at some point on the surfboard, this will split into two. The double concave is better suited to the heavier surfer. The double concave near the tail allows for looser turns and freer maneuvers. The single concave at the front gives the surfboard superior drive on the wave.

V Concave. A V concave in the tail can work really well with longboards because it will loosen up the tail making your longboard more maneuverable. They also work great on the retro fish surfboard designs. The extra width of the fish tail gives you heaps more speed on the smaller waves. Placing a V concave on your board allows the surfer to turn the board from rail to rail. This makes the surfboard much looser. A win-win situation, speed and loose turns on small waves.

The Flat Bottom. The bottom of this surfboard has no contours. This design is typically a way for a surfboard company to save time and money. You will find no concaves on your cheaper surfboards and although there are a few exceptions, flat bottom boards perform and a much lower level. There are many combinations of concaves that a board can have from the above list. The concave setup that a board has will dramatically change the way it surfs.