| 摘要 |
An instrument for measuring rigger-spread of a boat has an elongate casing 1 for support athwartships of the boat with a shoulder 2 of the casing 1 abutting the outside of the gunwale 4 opposite the rigger 5 and a slidingly-adjustable shoulder 6 abutting the opposite gunwale 9. A measuring tape 10 is extendable longitudinally from the casing 1 to the oarlock 14 of the rigger 5 to give a reading of spread, the extendable length being limited in dependence upon the spacing between the shoulders 2,6 of the casing 1 such that this length is increased or decreased by half the amount of any increase or decrease, respectively, of that spacing. Limitation of the extendable length involves a mechanism in which the two ends 18,19 of a flexible strip 15 or wire are secured respectively to the sliding shoulder 6 and the casing 1 so as to define a loop that is caught by a hook 16 of the tape 10 in limiting tape-extension. A modified limiting mechanism involves a step-down 2:1 coupling via pinions 23,24 between a rack 22 fixed to a sliding shoulder 20 and a rack 25 that engages a stop pin 26 of the measuring tape 27.
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