Crossword clue: the notch, fork, or other device on the gunwale of a boat, in which the oar rests in rowing. see rowlock.
1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).
Possible answers
a holder attached to the gunwale of a boat that holds the oar in place and acts as a fulcrum for rowing