Futtock (frame)
In the construction of a wooden-hulled ship, the futtocks are the separate pieces of timber which compose the frame of the ship. There are four futtocks (component parts of the rib), and occasionally five, to a ship. Those next to the keel are called ground-futtocks, or navel-futtocks, and the rest are termed upper futtocks. The word itself is derived from a contraction of 'foot hook', indicating their role in providing a secure framework to a ship.
Read more about this topic: Futtock Shrouds