單項選擇題

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

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單項選擇題

Structural bulkheads on a ship are usually（）.

A.continuous
B.watertight
C.transverse
D.non-watertight

單項選擇題

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