heaving line
Nautical term for a light line thrown from a ship to shore or to another vessel, used to pull a heavier mooring line across.
The sailor threw the heaving line toward the shore.
Compound of 投げ (nage, 'throwing') + 綱 (tsuna, 'rope'), literally 'throwing rope'. The reading なげづな follows rendaku voicing of つな to づな.