When a pushing vessel and a vessel being pushed are rigidly connected in a composite unit，they shall be regarded as（）.

单项选择题What determines if a vessel is restricted in her ability to maneuver?（）.

A.Whether or not all of the vessel's control equipment is in working order
B.The vessel's draft in relation to the available depth of water
C.Whether the nature of the vessel's work limits maneuverability required by the Rules
D.Whether or not the vessel is the give-way vessel in a meeting situation

单项选择题Vessels shall be deemed to be in sight of one another only when one（）from the other.

A.can be observed visually
B.can be observed by radar
C.can be located on the radar
D.can be heard

单项选择题Vessel underway means that a vessel is（）.

A.on the way
B.at anchor
C.made fast to a terminal
D.moving against water

单项选择题Vessel constrained by her draught is（）.

A.a non-power driven vessel
B.a sailing vessel
C.a power driven vessel
D.a power driven vessel or a non-power driven vessel

单项选择题Underway vessels shall at all time maintain a proper look-out（）.

A.by sight and hearing only
B.by all available means besides sight and hearing
C.by all available means except sight and hearing
D.by none of above means