"Amain, at once, suddenly; as, let go amain! i.e. let it run at once. This phrase is generally applied to any thing that is hoisted or lowered by a tackle, or complication of pullies.
"To lower amain, to lower at once, or let go the fall of the tackle. To strike amain, to lower or let fall the topsail. To wave amain, to make a sign to another vessel by waving a bright sword, or something else as a demand for striking its topsails." —Falconer's New Universal Dictionary of the Marine (1816), 9
"Amain, at once, suddenly; as, let go amain! i.e. let it run at once. This phrase is generally applied to any thing that is hoisted or lowered by a tackle, or complication of pullies.
"To lower amain, to lower at once, or let go the fall of the tackle.
To strike amain, to lower or let fall the topsail.
To wave amain, to make a sign to another vessel by waving a bright sword, or something else as a demand for striking its topsails."
—Falconer's New Universal Dictionary of the Marine (1816), 9