Retractable centre-board for boat - has linkage to control rotation about vertical axis which alters heading

摘要

The centre plate (a) fitted to the boat's hull (b) is capable of rotation about the horizontal axis at (c) so that the plate may be raised or lowered from its position in the centre plate casing. The plate is also capable of rotation about the two bearing points mounted on the same axis (2). The rotation is limited in this plane by the width of the centre plate casing. The rotational movement may be controlled by an outside link mechanism which causes the plate to rotate about a vertical axis thus affecting the relative head of the vessel to the sea.