单项选择题 A mooring line is described as being 6x24，1-3/4 inch wire rope. What do the above numbersrefer to?（）

单项选择题 A Danforth lightweight anchor does NOT hold well in which type of bottom? （）

单项选择题 Your 15-meter tug is underway and crossing a deep and narrow channel. A large container vessel is off your port bow on a steady bearing. Which statement is TRUE concerning this situation? （）.