单项选择题
A.The light is characterized as alternately flashing
B.The lighthouse has lost power and has switched to emergency lighting
C.It is the identifying light characteristic of the lighthouse
D.You have entered an area of shoal water or other hazard
单项选择题 You are docking a vessel starboard side to with the assistance of two tugs.You are attempting to hold the vessel off by operating both tugs at right angles to the vessel and at full power.You must ensure that（）.
单项选择题 Winds expected to（）Storm Force 10 in south-east semicircle later up to 300 miles from the center of the tropical cyclone.
单项选择题 While your vessel is docked port side to a wharf，a sudden gale force wind causes the vessel’s bow lines to part.The bow begins to fall away from the dock，and no tugs are immediately available.Which measure（s）should you take FIRST（）.