About Vort-X Tunnel fins:
The vort-X tunnel fin is based on the principle of the annular wing, and is the lowest drag highest drive fin configuration possible, this is partly because
a) It has no drag inducing fin tips,
b) Because of the even distribution of water pressure inside the tunnel ( A geater volume of water is redirected with less drag between water layers ) , and
c) Because the fin organises flow by slightly twisting the water water flow into a vortex as it passes through the tunnel, this prevents random turbulence and reduces drag.
Also, the tunnel fin has a large amount of horizontal lift area, this provides lift at a better lift/drag ratio than planing hulls can achieve, the tunnel is set up to work in conjunction with the planing surface, the benefit being that the tail area has the equivalent of a wide surface with lots of area, while keeping a narrow tail for control.
The horizontal area in the tunnel fin also acts as a means of transferring rider energy into forwards thrust through board flex . . . basically it's like a dolphin tail. . . the board pumps up and down and drives the 'fluke' at the tail.. . . this happens even with subtle weighting and unweighting.
The ability of the tunnel to organise flow means that (in the case where a central fin is used in front of the tunnel) any turbulence coming off the triling edge and base of the front fin is organised into a lower drag flow pattern.
The tunnel has the advantage of ZERO rail to rail resistance
Riding a vortex tunnel equipped board is like entering another dimension.
