Jacket and case manufacture. 1  3 The jackets of the 8-inch and 5 1/4-inch disks are cut out of polyvinyl chloride (PVC) stock to appropriate size, and the fabric liners laminated to them. 2  4 The case or shell of 3 1/2-inch disks is molded out of hard plastic.
Aft: generally anything astern of the z-axis mid-line of a vessel; diminutive of the word after. Bow: the forward section (or fore) of a ship. Stern: the rear section (or aft) of a ship. Port (side): the left side of a ship from the perspective of a person standing on board and facing the bow of the ship on the bridge. Starboard: the right side of a ship from the perspective of a person standing on board and facing the bow of the ship on the bridge.
The head aboard a Navy ship is the bathroom. The term comes from the days of sailing ships when the place for the crew to relieve themselves was all the way forward on either side of the bowsprit, the integral part of the hull to which the figurehead was fastened.