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單項選擇題

The circular steel structure installed around the propeller of a towboat is the（）.

A.nozzle
B.shroud
C.strut
D.hood

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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

單項選擇題

Structural bulkheads on a ship are usually（）.

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