Sailing boat inbuilt hull motor uses cover plate horizontalizing when extended and retracting at angle adapted to hull using lifting arm.

摘要

The cover plate (6) is fixed to a lifting arm (4) so that when the plate is fully extended the impinging water horizontalizes the plate so it retracts at the hull angle. The plate pivot point (7) is arranged so the larger surface of the plate lies astern. The arm slopes from the pivot (7) up at an angle to the rear edge to ensure that the retracting plate (6) fits the hull but only so the slope of the arm keeps the plate clear of the propeller. The arm presents a hollow tube containing a hollow cylinder (2) which is fixed to the bottom end of the arm and at the top the draw-in shaft (8), thus minimizing the height of the shaft.