单项选择题
In towing，heaving lines are used for（）.
A.passing a tow bridle to the tug B.passing a messenger line C.heaving in the tow bridle D.service lines with rocket line throwers
单项选择题 In towing it is desirable for the tug and the vessel to ride wave crests simultaneously because（）.
单项选择题 In order to back a right-handed，single-screw vessel in a straight line，you will probably need to use（）.
单项选择题 In order for a vessel to be engaged in fishing she must be（）.
