单项选择题
A chart position enclosed by a square is a(n)（）.
A.fix B.estimated position C.dead reckoning position D.running fix
单项选择题 A change of a documented vessel’s name can only be made by the（）.
单项选择题 A chain bridle is used when towing astern because it（）.
单项选择题 A chain bridle is preferable to a wire rope towing bridle on a long ocean tow because chain（）.
