单项选择题
Structural stress on a ship can be reduced by（）.
A.lessening the effect of environmental forces B.even and symmetrical variable loading C.local concentration of heavy consumables D.increasing the metacentric height
单项选择题 Structural stress levels in a ship are the sum of loading stresses and stresses due to（）.
单项选择题 Keel scantlings of any vessel are greatest amidships because（）.
单项选择题 It is possible，and sometimes necessary，to strengthen the deck of a vessel for carriage of deck cargo by（）.
