Sailing vessels are stand-on over power-driven vessels except（）.

单项选择题Risk of collision is considered to exist if（）.

A.four vessels are nearby
B.a vessel has a steady bearing at a constant range
C.there is any doubt that a risk of collision exists
D.a special circumstance situation is apparent

单项选择题Power-driven vessels must keep out of the way of sailing vessels except（）.

A.in a crossing situation
B.when they are making more speed than the power-driven vessel
C.when the sailing vessel is overtaking
D.on the Inland Waters of the United States

单项选择题On open waters，a vessel fishing is in a crossing situation with a vessel sailing located on the fishing vessel’s starboard side. Which vessel is the stand-on vessel?（）.

A.The fishing vessel because it is to port of the sailing vessel
B.The fishing vessel because it is fishing
C.The sailing vessel because it is to starboard of the fishing vessel
D.The sailing vessel because it is sailing

单项选择题On open waters，a power-driven vessel shall keep out of the way of a（）.

A.vessel on her port side that is crossing her course
B.vessel that is overtaking her
C.seaplane on the water
D.sailing vessel

单项选择题It has often been stressed in the Courts that the look-out man should，preferably，be stationed forward，unless weather conditions make this（）.

A.possible
B.practicable
C.impossible
D.probably