A.the change in difference between the forward and aft drafts
B.the sum of free communication, free surface and pocketing
C.the moment of inertia of the ship's waterline plane about the athwartship axis
D.rolling and listing

A.any deck below the main deck and above the lowest deck
B.a member that gives fore-and-strength
C.made by placing two bulkhead a few feet apart
D.a heavy fore-and-aft beam under the deck