单项选择题
A.The testing of the internal combustion engine driven emergency generator at least once each month the vessel is navigated
B.The testing of storage betteries for emergency lighting and systems once each 6 months the vessels is navigated
C.The actual draft when the vessel arrives in salt water after department a port
D.The testing of the line-throwing appliance once every 3 months
单项选择题 （）of the following statements is incorrect regarding a fire and boat drill ao board your cargo vessel.
单项选择题 （）refers to the angle between true North and heading line of the vessel.
单项选择题 （）the incomplete nature of the survey ,heavy draught vessels warned not to navigate within the 10 fathom line.