单项选择题
A.heavy-walled drill pipe B.tool joint C.down hole tool D.drill collar
A heavy steel curved arch constructed athwartships and ...
单项选择题A heavy steel curved arch constructed athwartships and above the after deck on a towing vessel is sometimes called a（）.
A.main brace B.tow span C.jockey bar D.None of the above
A head-on situation at night is one in which you see de...
单项选择题A head-on situation at night is one in which you see dead ahead a vessel showing（）.
A.one sidelight B.one sidelight and a masthead light C.one sidelight and two masthead lights D.both sidelights of a vessel and her masthead light(s)
A hand held instrument used to measure distances betwee...
单项选择题A hand held instrument used to measure distances between objects and the ship is a（）.
A.vernier B.psychrometer C.hygrometer D.stadimeter
