单项选择题
A.my vessel is leaking
B.my vessel is producing fresh water
C.my vessel is producing sea water
D.sea water is de-salted on board my vessel
单项选择题 Land-based authority conducting and co-ordinating search and rescue operations in a designated area defines（）.
单项选择题 Moving of an anchor over the sea bottom involuntarily because it is no longer preventing the movement of the vessel defines（）.
单项选择题 Moving of an anchor over the sea bottom to control the movement of the vessel defines（）.