Webster's 1828 Dictionary
SWIFTER
n.In a ship, a rope used to confine the bars of the capstan in their sockets, while men are turning it; also, a rope used to encircle a boat longitudinally, to strengthen and defend her sides from the impulse of other boats. Swifters also are two shrouds fixed on the starboard and larboard sides of the lower masts, above all the other shrouds, to give the masts additional security.
SWIFTER
v.t.To stretch, as shrouds by tackles.
Webster's 1913 Dictionary
SWIFTER
Swift "er, n. Etym: [Cf. Swivel. ] (Naut. )(a ) A rope used to retain the bars of the capstan in their sockets while men are turning it. (b ) A rope used to encircle a boat longitudinally, to strengthen and defend her sides.(c ) The forward shroud of a lower mast.
SWIFTER
SWIFTER Swift "er, v. t. (Naut. )
Defn: To tighten, as slack standing rigging, by bringing the opposite shrouds nearer.