a purchase in which two or more blocks are used in order to multiply the power exerted on a rope. The gain in power is equivalent to the number of parts which enter and leave the moving block of the tackle, depending on whether it is rigged to advantage or disadvantage. Before the introduction of auxiliary power, tackles were employed for most lifting and or moving jobs in a vessel. There were many types, depending on their purpose and also on the number and nature of the blocks used.
Subjects: Maritime History — Warfare and Defence.