单项选择题
Which device is designed to automatically hold the load if power should fail to an electric winch?（）
A.Pneumatic brake B.Electromagnetic brake C.Hand brake D.Motor controller
单项选择题 When the pilot is embarked he or she（）.
单项选择题 When must the Master or person in charge of a ship log the position of load line marks in relation to the surface of the water in the logbook?（）
单项选择题 What is the purpose of the limit switch on gravity davits?（）
