单项选择题
A.nozzle B.shroud C.strut D.hood
The bow thruster generally is ineffective at（）.A.over 3...
单项选择题The bow thruster generally is ineffective at（）.
A.over 3 knots headway B.at any speed astern C.at any speed ahead D.over 1 knot sternway
Structural bulkheads on a ship are usually（）.A.continuo...
单项选择题Structural bulkheads on a ship are usually（）.
A.continuous B.watertight C.transverse D.non-watertight
Signs of racking stresses generally appear at the（）.A.b...
单项选择题Signs of racking stresses generally appear at the（）.
A.bow and stern shell frames and plating B.junction of the frames with the beams and floors C.garboard strake，at each side of the keel D.thrust bearing of the main shaft
