| 摘要 |
<p>A keel comprising two mutually inclined fins (1, 2) which are movable relative to a hull on which the keel is mounted and means such as releasable ratchet devices (31, 32) for locking the fins in any of a plurality of positions relative to the hull. The keel may thus be selectively positioned asymmetrically with respect to the hull to give improved performance and to provide a stable base on inclined surfaces. </p> |
