单项选择题 If a vessel under tow starts jumping on its tow line，the most appropriate action to alleviate the condition is to（）.

单项选择题 If a towing vessel and her tow are severely restricted in their ability to change course，they may show lights in addition to their towing identification lights. These additional lights may be shown if the tow is（）.

单项选择题 How does the effect known as bank suction act on a single-screw vessel proceeding along a narrow channel?（）.