Tunnel fin

The weight and length of these boards make it easier to control the fore and aft angle of the tunnel.

Tunnel fins were first used by Richard Deese and Bob Bolen (also known as the Greek) in California during the late sixties and continue to be developed by shapers today.

The tunnel fin has a large amount of horizontal lift utilizing the hydrofoil principle providing better lift-to-drag ratio.

The horizontal area in the tunnel fin also acts as a means of transferring rider energy into forward thrust through board flex (similar to a dolphin tail).

The ability of the tunnel to organize volumetric flow rate means that (in the case where a central fin is used in front of the tunnel) any turbulence coming off the trailing edge and base of the front fin is organized into a lower drag flow pattern.