Surfboard Bottom Contour
The Surfboard Bottom Contour is easily one of the more complex and misunderstood concepts pertaining to surfboard design, because we are dealing with some pretty heady concepts.
Basically the bottom contour purpose is to influence the way the water (wave) flows beneath it.
The contour will decide how fast or slow a surfboard goes and the abiltiy to control and turn it.
There are a few basic bottom shapes Flat, Concave (single and double) Convex or “V”
This was used on the first surfboards. It literally meas flat, no contour whatsoever.
Flat Bottoms are good for slow mushy waves and they respond well in these type of conditions, surf them in powerful or big waves and these will be difficult to control.
Concave bottoms can have a “single” and/or “double” concave.
A surfboard with a single concave will have 1 concave from rail to rail. The concept is that concave on the bottom of a surfboard will provide lift which facilitates water flow.
This bottom contour works well in large clean surfing conditions.
Double concave is just that, 2 sets of concave on a surfboard.The concept behind double concave is the double concave splits the water into two channels through the fins and creates a much looser ride—great for flowing maneuvers. Double concaves are one of the more popular bottom designs found on modern shortboards. Generally a surfboard will have a single concave at the nose and then turn into a double after the midpoint down towards the tail.
This is the opposite off concave. Vee is used to loosen up the tail at high speeds and increases the rocker at the rail line which makes boards turn more easily.
Overall Vee makes a surfboard easier to surf rail to rail. This bottom contour works well in LARGE surf.
The contour of the deck determines the rail-to-rail foil of a design, as the deck can be flat, domed, concaved, or anything in between.
In general, the flatter the deck, the further the deck volume is carried out to the rail, and the greater volume the overall board will have. This design is intended for stability and drive.
The more domed the deck, the more concentrated the volume will be along the stringer, and the less overall volume board will have. This design is intended for loose, rail-to-rail surfing.
Concave decks are generally variation of spoon designs, where volume is reduced along the stringer to lower the rider’s center of gravity and provide greater flex.
Its important to remember that the surfboard bottom contour and deck contour are very important to the overall design of the surfboard but must integrate well with every other aspect of the surfboard to create an aesthetically pleasing and functional board.