单项选择题
（）is used to prevent the entry of sea water to the machinery space.
A.A special sealing gland B.Propeller C.Tailshaft D.Sterntube bearing
单项选择题 The thrust from the propeller to the hull of the ship is transferred by（）
单项选择题 The transmission system transmitting power from the engine to the propeller is composed of shafts, bearings, and（）
单项选择题 Which of the followings will affect the spray of fuel oil?（）
