Snub, to

To jerk on a rope or a chain sharply. The boat may do
it herself, snubbing at her anchor cable in heavy weather – that’s to say
coming up short on the cable with a jerk. A Snubbing winch is a small winch
consisting of a drum with no lever but with a ratchet mechanism so that when
you shorten a rope turned around the drum it acts as a brake. A snubbing line has a hook on the end that goes through a link in the anchor chain to take the strain off the windlass.