We often read surfboard design articles which state that wide nosed surfboards, particularly those with low nose rocker, are prone to nose diving and/or having the nose rail 'catch 'What we don't hear about is that this is not due to nose shape but to tail shape. It is the shape of the tail which determines how the nose is presented to the water. . . and the problem is that parallel railed wide tailed boards drive the nose of the board in during turns.The cure is to narrow the surfboard tail, thus increasing rail convergence.Pulling the tail in means that when the board is rolled on to the rail even slightly ( which also gets easier to do with a narrower tail ) the nose is lifted out of the water. . . it actually works even better if the nose goes wider.Here's a balsa 9'1" with an extremely pulled in tail. . . no nosediving at all even though it has only an inch of rocker:
Once you get the idea it's really obvious but it's a bit hard to explain, I'll try to do it with a diagram:
The rail convergence lifts the nose partly because it rotates the board on the axis of the rail rather than the central axis, and partly because it drives the nose forward and upwards.With a pintailed board or any board with a drawn in tail, the rider can always avoid the nose digging in by starting a turn. . . . this lifts the nose. The rider of the wide tailed board does not have this luxury. . . attempting to turn only makes the problem worse by digging the nose rail in. Two added bonuses of the narrow tail are 1) that these nose lifting turns are made easier to initiate with a narrow tail due to lower rail to rail resistance, and 2) that the turns can be done in steep parts of the wave because the narrow tail holds in to the wave better.Once again we have a surfing problem which is cured entirely by avoiding the ice cream stick parallel railed wide tailed noseriding longboard shape. . . it really is the root of many surfboard evils.
Once you get the idea it's really obvious but it's a bit hard to explain, I'll try to do it with a diagram:
The rail convergence lifts the nose partly because it rotates the board on the axis of the rail rather than the central axis, and partly because it drives the nose forward and upwards.With a pintailed board or any board with a drawn in tail, the rider can always avoid the nose digging in by starting a turn. . . . this lifts the nose. The rider of the wide tailed board does not have this luxury. . . attempting to turn only makes the problem worse by digging the nose rail in. Two added bonuses of the narrow tail are 1) that these nose lifting turns are made easier to initiate with a narrow tail due to lower rail to rail resistance, and 2) that the turns can be done in steep parts of the wave because the narrow tail holds in to the wave better.Once again we have a surfing problem which is cured entirely by avoiding the ice cream stick parallel railed wide tailed noseriding longboard shape. . . it really is the root of many surfboard evils.
