They are trying to ________ the waste discharged by the factory for profit. A．expo

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

While underway and towing an unmanned tank barge you are required to ______.

A.maintain a strict watch on the barge from the towing vessel

B.fly a red flag from the towing vessel

C.open the tops of all empty tanks on the barge

D.take hourly soundings of any loaded tanks on the barge

A vessel aground would show the same dayshape as a ______.

A.vessel towing a submerged object

B.dredge underway and dredging

C.hydrographic survey vessel at anchor and surveying

D.None of the above

A.need not show the lights for a vessel engaged in towing，if it is impractical to do so

B.may show the lights for a vessel not under command

C.must show a yellow light above the stern light

D.must show the lights for a vessel towing

A. insure that the hawser leads directly aft as it passes over the stern of the towing vessel

B. increase the stability of the towing vessel by raising the hawser off the deck

C. reduce chafing of the towing hawser

D. prevent fouling of the hawser on deck gear located on the stern of the towing vessel

A.pushed ahead

B.towed alongside

C.towed astern

D.Any of the above

A.the masthead lights for a towing vessel

B.the lights for a vessel restricted in its ability to maneuver

C.sidelights，stern light and towing light

D.All of the above

You see a vessel carrying a black diamond which indicates a ().

A.vessel towing astern

B.barge pushed ahead

C.vessel towing astern only when the length of her tow exceeds 200 meters

D.this signal does not exist in international waters

A.directly astern and pushing the tow

B.towing on a hawser

C.towing alongside and parallel to the vessel it is towing

D.towing on the hip