Speedboat hull with central groove - has longitudinal groove gradually increasing in depth, to full depth at central step, forming two lobes

摘要

The hull of a speedboat has a groove down the middle extending almost from the pointed tip. About half way along, there is a slot (18) for a retractable keel (22) and a stop (22) where the slot is almost the whole depth of the hull. At the front, the groove gradually increases in depth and also widens, until it reaches the stop. The underside (12c) of the remaining solid port is formed by a smooth convex curve. After the step, the groove is a more sharply sided V shape, and gradually decreases in depth, towards the rear, between two lobes (14t). Nearer the centre, the lower outside surfaces of the lobes, forming the load supporting surfaces are at an angle to the horizontal which gradually decreases until the surfaces are horizontal and flat.