unreeve

verb

1. (transitive)To withdraw or take out, as for example a rope from a block.

   “He could not only splice a broken "fall," and repair the sheaves and friction-rollers in a hoisting-block, but whenever the rigging got tangled aloft he could spring up the derrick like a cat and unreeve the rope in an instant.”

   “But he carried all sail till the rotten main-sheet parted at the boom, and when he came up in the wind to lower the sail the main throat halyard refused to unreeve.”