Traditional hauling and purchasing technique. If one end of a rope is made fast and the other is

passed around a log, say, then as you pull the free end the log rolls towards

you. In effect the log plays the part of a sheave in a block, and you get the

two-to-one purchase of a single whip. You may still see the occasional

drayman lowering a barrel into a cellar by parbuckling. A possible use for the

yachtsman is to get an inert body from the water to deck level, perhaps using a

sail in place of the rope.