单项选择题
A.60 fathoms
B.the distance from the main deck to the light waterline
C.twice the distance from the main deck to the light waterline or 50 feet whichever is greater
D.two times the distance from the boat deck to the light waterline or 50 feet whichever is greater
单项选择题 The margin plate is the（）.
单项选择题 The main advantage and chief characteristic of a Steulchen boom is that it can be（）.
单项选择题 The lifeboats on your vessel are stowed on cradles on deck and are handled by sheath-screw boom davits. Which of the following statements about launching a boat is TRUE?（）