Catch a Crab
(To). In rowing, is to be struck with the handle of one's oar; to fall backwards. This occurs when the rower leaves his oar too long in the water before repeating the stroke. In Italian granchio is a crab, and pigliar il granchia is to “catch a crab,” or a Tartar.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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