A surfboards overall shape is determined by the boards dimensions. It’s length, width and thickness will affect the boards buoyancy where rocker or the board curve will affect the way it paddles and reacts on the waves face.
A surfboards dimension uses the following 6 measurements:
- Length: the measurement from the nose to the tail of a surfboard;
- Width: the measurement from rail to rail of a surfboard;
- Thickness: the measurement of a surfboard from deck to bottom;
- Outline: the overall shape of a surfboard;
- Rocker: the amount of curve a surfboard has from the tail to the nose;
- Concave: a contour on the bottom of the board
Furthermore, a surfboards shape can be described by the following features:
- Nose: the front tip (first 12 inches) of the surfboard;
- Tail: the rear end of the surfboard, influencing speed and maneuverability;
- Rails: the sides of the surfboard;
- Stringer: the material strip that runs down the middle of the board, which increases strength and reduces unwanted flexibility;
- Fins: a surfboard accessory inserted into the tail of the surfboard to help control the surfboard..
Dimensions of a Surfboard
Length – This is the measurement of a surfboard from nose to tail. A longer surfboard will offer more paddling power and stability. The large surface area allows the surfer to paddle faster and get into larger waves.
Width – This is the measurement of a surfboard at its widest point. A wider shape will allow the surfer to eliminate a few inches of length without sacrificing paddling or planing speed. The location of the surfboard’s wide point deserves careful consideration as it will affect riding style and turning radius.
Thickness - Thickness is measured by the thickest part of the board which is typically located around the mid section. Most surfboards are between 2 1/4" - 3 1/4" thick. The heavier you are, the thicker your surfboard should be for extra float. If your board is too thin, you sink the board making it tough to paddle and catch waves. A thicker board is also stronger and more resistant to breaking.
The rocker is the curvature of the surfboard’s profile or the bottom curve of a surfboard from the tail to the nose. The foam blank comes with a particular rocker that the board shaper can alter a bit, but not drastically. A more dramatic rocker will make it easier to handle steep drops, facilitate tighter turns, but also slow the board down if it is heading in a straight line. You can also split the rocker into Nose & Tail.
A surfboard’s bottom contour or concave contributes to the speed, turning ability, and style of ride. Whatever the design, it will affect the board’s performance. Designs will vary however the main contours are Convex, Concave, Flat, Vee and Channel.
Single to Double Concave
The most common bottom contour is a single concave leading from the nose which fades into a double concave as it nears the tail. The single concave upfront provides a good plaining surface for drive and the double concave in the rear loosens up the board. The double concave will actually channel the water into two streams through the fins and out the tail.
The single to double concave is the bottom contour of choice for most modern shortboards. It utilizes the strengths of each design while muting their disadvantages. It reduces the tracking of a single concave while still allowing for a fast ride and a loose feel to the surfboard.
A single concave channels water from the front of the surfboard until it passes the fins and out the tail of the board. The design allows for faster surfing and works very well in large clean surf. It is not particularly versatile as it does not do well in choppy surf, but the speed makes it a very popular choice.
A Flat bottom will hit down on a wave rather than part the water, making it easy to plane.
A Vee bottom is easy to lean from rail to rail. The Vee design is in the back of the board, making the tail very responsive.
A Channel bottom has several grooves in the back part of the board, which makes the water flow turn into a forward thrust increasing the boards speed.
Components of a Surfboard
The nose is the front of the surfboard. This aspect of surfboard design plays a large role when dropping into waves. Noses will vary in width, curvature and thickness. There are two basic types of surfboard nose:
Most high performance boards, like thrusters, have a pointed nose. The pointed shape adds more rail curve to the plan shape when compared to a round nose longboard.
This shape allows for the front of the board to have more surface area, giving the board more stability. Longboards typically have a round nose for the purpose of allowing the surfer to nose-ride. Round nose boards make it easier to paddle, glide, and plane on the surface because it helps to keep more of the surfer out of the water.
The tail is the rear end of the surfboard. It has various shapes, performance characteristics and rockers.
Pin tails have narrow width at the end. Minimal width allows the rider to maintain direction (control). This design gives you maximum water flow without any abrupt release for better hold. They can be difficult to maneuver so they are not recommended for small waves. Guns are usually designed with this pin tail end.
Designed for: maximum traction and control
Round Tails allow water to wrap around its contour for better traction. It has more width than a pin tail and thus more versatile. The added width increases the surface area, which increases lift. More lift allows the board to become easier to turn. With the curve shape, you should expect more round, drawn out turns. The added surface area will also provide more speed (in slow spots).
Designed for: lift, traction and easy turns.
The squash tail is the most common type. The square end allows for quick release, which makes the board very responsive. Sharp and loose turns can be performed with this tail. Similar to the round tail, more surface area means more lift or easier to plane and maintain speed.
Designed for: control and tracking in high speeds.
Fish tails were designed similar to the pintail in that the two points will give the board more hold and traction. This type allows for a wider tail and larger surface area. This means it makes it easier to maintain speeds and offers better paddling power.
Designed for: maintaining speed, hold and traction
The square tail is wide and helps add stability. The extra width in the tail means the surfboard will have less curve in the rails. Because the square tail has corners, they dig in to a wave while you are turning, which helps increase the ability of a surfboard to make pivotal turns.
Designed for: maintaining stability and making pivotal turns
The diamond tail is a variant of the square tail. It is designed to soften up the square tail whilst keeping optimal speed. Like the square tail it is wide aiding in stability.
Designed for: maintaining stability and speed.
A Flyer can be introduced into the tail section of the board to reduce overall tail size whilst providing a pivot point for shorter and tighter turning arcs. The introduction of a flyer is a great addition for smaller surf.
Designed for: short and tighter turning arcs
These are the outer edges or sides of the surfboard. They impact tube riding, planning speed, and turning.
In general, there are two types of rail design: hard and soft. Soft rails are rounded and hard rails will have hard edges. Rails will usually be thicker in the middle of the deck and thinner at the nose and tail.
Performance wise, a hard rail will make it easier to turn quickly because the hard edge cuts into the water. However, they make pivotal turns very hard. You will normally see these on high performance boards.
Soft rails are suited to Longboards because they allow the rider to take advantage of a fin’s turning radius. They also help to paddle a lot easier and maintain speed. However, they do create more drag.
A rounded rail which looks almost like a complete semi-circle
A description of the point where the bottom of the rail meets the top. This indicates the meeting point is in the middle of the rail.
Again, this is a description telling us the rail's point is slightly lower than centre.