What is a heavy casting of metal, usually fixed near the gunwale. It has two short horn-shaped arms curving inward, between which ropes or hawsers may pass for towing, mooring, etc called?

chock — (Naut.) A heavy casting of metal, usually fixed near the gunwale. It has two short horn-shaped arms curving inward, between which ropes or hawsers may pass for towing, mooring, etc. (Webster's 1913.)

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