| 摘要 |
Keel or fin (1) for a watercraft such as a surfboard is conventional in shape but comprises major portion (2) fixed to the board by peg (10) and minor, flexible, trailing portion (3) fixed to major portion (2). Minor portion (3) has a more rigid leading edge (16) which slides dovetail fashion onto trailing edge (8, 9) of major portion (2) and is locked in place by grub screw (7). Minor portion (3) has core (11) of rubber allowing it to flex sideways under water pressure. Excessive movement of trailing edge (12) of minor portion (3) is prevented when edge (12) contacts stops (4) positioned on either side on the board. Minor portion (3) may be completely surrounded in an aperture in major portion (2) or may have apertures to which air is fed via ducting.
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