Blank

Rough molded foam core that comes in different basic designs and rockers depending on the length and type of surfboard being shaped. Usually made from polyurethane foam.

Bottom Contour

The lateral curve of the bottom of the board as it runs from rail to rail. Can be concave or convex.

Carbon Fiber

A type of super-strong fiber, soakable in resin, which is occasionally laid in strips along the length of a board during glassing to help prevent creasing.

Channels

The channel surfboard bottom consists of flat planes that are designed in a concave configuration. They typically number from four-to-eight channels and direct water flow down the length of the channel. Since the channels sit side by side to each other the water is not being compressed as it is in a full concave. These concave configurations of each channel propel water down the back underbelly of the surfboard and convert this into forward thrust. Longer and deeper channels give a more pronounced effect.

Concave

The main purpose of concave is to channel the water flow down the length of the surfboard. This channeling of the water through the center and squeezed out the tail add more lift and responsiveness to the surfboard. Concaves are a very important design feature and can cause a board to track swiftly and improve tail responsiveness for critical turns.

Drag

The effect that causes water flow to be slowed or disrupted as it passes along a surfboard’s surfaces. Controlled drag is an essential requirement of surfboard design.

Epoxy

Type of plastic resin used by some manufacturers in place of polyester resin. Usually an epoxy-user also uses a polystyrene blank, which can be badly affected by polyester resins. Known for its durability.

EPS Expanded Polystyrene

A type of foam also known as styrofoam or bead foam. Polystyrene beads are expanded by steam in a mold with desired density determined by quantity of beads expanded within that mold.

Foil

The distribution of foam from nose to tail on a surfboard. Obviously for the board to flow correctly it must be evenly balanced thru the shape. If there is excessive foam left in the nose center or tail or dips and bumps it will create uneven flow and cause the surfboard to be unbalanced.

1. The rate of change of thickness from nose to tail of a surfboard.
2. The rate of change of thickness of a surfboard fin from its front to its back edge.

Polyurethane

A type of plastic foam; the most common type used in surfboard manufacturing, usually employed together with polyester resin.

Rails

The perimeter of the board. There are several different main types of rails which all produce a different effect:

• Round Rail - a round rail that is almost a complete semi-circle
• Down Rails - (Down Turned Rails) a rail coming to an edge at the bottom of the board
• Rolled Rails - Down Rails that are rolled under the board
• 50/50 - A proportional description of a rail shape 50/50 as in he widest point of the rail
is at the mid point of the rail i.e. a of rail
• 60/40 - A proportional description of a rail w here the widest point is towards the bottom

Release

The effect that allows water flow to be accelerated as it passes along a surfboard’s surfaces. Causes of release are usually available in the second (tail) half of the board, through tail rocker, outline curves and trailing fin edges, and through bottom features which open up opportunities for water to move, such as concaves and channels. Controlled release (along with its opposite, drag) is essential to successful surfboard design.

Rocker

Rocker is the curve of your surfboard from nose to tail. It can be broken down into different sections such as nose rocker, tail rocker, and center.

Vee

The opposite of concave, vee is used to loosen up the tail at high speeds by increasing the rocker at the rail line, making it easier to lean on edge and turn.