单项选择题
A.raised flange at the main deck edge
B.riveted crack arrester strap on all-welded ships
C.riveting pattern most commonly used in ship construction
D.row of plating nearest the keel
单项选择题 The function of the bilge keel is to（）.
单项选择题 The fore and aft run of deck plating which strengthens the connection between the beams and the frames and keeps the beams square to the shell is called the（）.
单项选择题 The floors in a vessel’s hull structure are kept from tripping，or folding over，by（）.