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.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.main string B.push string C.power string D.face string