单项选择题
A.than B.then C.when the line pull reaches the breaking strengh of the fall D.while
The center of volume of the immersed portion of the hul...
单项选择题The center of volume of the immersed portion of the hull is called the（）.
A.center of buoyancy B.center of floatation C.center of gravity D.tipping center
The collision bulkhead shall be of（）.A.water-tightB.air...
单项选择题The collision bulkhead shall be of（）.
A.water-tight B.air-tight C.fire-tight D.oil-tight
The deck control valve to be（）after being repaired.A.mo...
单项选择题The deck control valve to be（）after being repaired.
A.moved and fitting again B.removed and refitted C.reproduced and put on again D.return and attached again
