PARBUCKLE, a contrivance used by sailors to lower a cask or bale from any heighth [sic], as the top of a wharf or key, into a boat or lighter, which lies along-side, being chiefly employed where there is no crane or tackle.
It is formed by fastening the bight of a rope to a post, or ring, upon the wharf, and thence pulling the two parts of the rope under the two quarters of the cast, and bringing them back again over it; so that when the two lower parts remain firmly attached to the post, the two upper parts are gradually slackened together, and the barrel, or bale, suffered to roll easily downward to that place where it is received below. This method is also frequently used used by masons, in lifting up or letting down large stones, when they are employed in building; and from them it has probably been adopted by seamen.
– Wm. Falconer’s Dictionary of the Marine (1780).