Manually-powered planing hull - has pivoted arms projecting beyond stern and carrying transverse holder for flexible fins

摘要

The planning hull, partic. sailboard, propulsion system using muscle power has one or more substantially horizontal fins mounted by their leading edges. The fins are free to flex in a transverse holder between longitudinal arms on transverse pivots clamped to the board and projecting beyond the stern. The arms extend forwards from the pivots and have an upright stirrup linking them so that they are operable standing up facing forward. A central steadying bar from the pivot support fits into the keel board slot and carries the rudder shaft, running through the slot, and pedal.