Tackle

A tackle (pronounced tay-kl at sea) is a purchase of rope rove through two or more blocks to gain mechanical advantage for hauling or lifting. The ideal advantage equals the number of rope parts at the moving block, ignoring friction: a single whip gives one, a gun tackle two, a luff tackle three, and a two-fold purchase four. Friction in the sheaves reduces real advantage and adds to the haul. Tackles work mainsheets, vangs, halyards, cargo derricks, and boat falls, the fall being the hauling part.