单项选择题
A.a vessel towing by pushing ahead B.a power-driven vessel，not towing C.a barge being pushed ahead D.either answer A or answer B
A towboat is pushing barges ahead at a dangerously fast...
单项选择题A towboat is pushing barges ahead at a dangerously fast speed when（）.
A.the towboat vibrates when backing down B.the roostertail exceeds the height of the main deck C.a strain is placed on the face wires D.water comes over the foredeck of the lead barges
A tow of 9 barges is made up three abreast and three lo...
单项选择题A tow of 9 barges is made up three abreast and three long. The towboat is faced up to the center string which is known as the（）.
A.main string B.push string C.power string D.face string
A spreader bar is used to（）.A.increase the lifting capa...
单项选择题A spreader bar is used to（）.
A.increase the lifting capacity B.increase the lifting radius C.protect the slings D.protect the upper part of a load
