Definition of relieving tackle in US English:

relieving tackle

noun

Nautical
historical
  • 1Tackles used on either side of a ship to prevent it overturning when being careened.

  • 2Purchases rigged on either side of a vessel's tiller to ease the strain, especially in heavy seas.

Origin

Early 18th century; earliest use found in William Sutherland (fl. 1711–1717).