How sea state limited a fast MTB

At what sea state could Vospers operate at maximum speed?

Full speed was intended for relatively calm water, around sea states two or three, though crews sometimes pushed boats hard in rougher conditions at considerable strain.

The expected full-speed sea state differed from the conditions in which crews actually pushed a boat. A planing hull relies on skimming over the water, so larger seas increasingly prevent it from holding its optimum speed. A fast boat might continue operating in sea states six or seven without being able to make maximum speed. Crews could bypass safeguards and accept severe vibration, but that did not remove the physical penalty of rough water.