单项选择题
A.relieves the officer of the watch
B.relieves the Master of his duties
C.is solely responsible for the safe navigation of the vessel
D.is a specialist hired for his or her local navigational knowledge
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?（）
单项选择题 What is the most important difference between the bow type anchor shackle and the D-type anchor shackle? （）