Long ropes extending from all mast-heads above a lower-mast to both sides of the ship or chain-wales; they are extended and set up with dead eyes and laniards to the backstay-plates. Their use is to second the shrouds in supporting the mast when strained by a weight of sail in a fresh wind. They are usually distinguished into breast and after backstays; the first being intended to sustain the mast when the ship sails upon a wind; or, in other terms, when the wind acts upon a ship obliquely from forwards; the second is to enable her to carry sail when the wind is abaft the beam; a third, or shifting backstay, is temporary, and used where great strain is demanded when chasing, chased, or carrying on a heavy pressure of canvas: they are fitted either with lashing eyes, or hook and thimble with selvagee strop, so as to be instantly removed.