A.implementedB.impliedC.impossibleD.improperIt is an（）c……

单项选择题In stopping distances of vessels，head reach can best be described as the（）.

A.difference between the vessel's speed through the water at any instant and the new speed ordered on the telegraph
B.distance the vessel has actually run through the water since a change of speed was ordered
C.distance the vessel will run between taking action to stop her and being stationary in the water
D.speed at which a vessel should proceed to ensure that she will run a predetermined distance，once her engines have been stopped

单项选择题If you do NOT understand the course or intention of an approaching vessel you should sound （）.

A.one short blast
B.one prolonged blast
C.not less than five short blasts
D.not less than five prolonged blasts

单项选择题If the PSCO from general impressions or observations on board has（）for believing that the ship，its equipment or its crew do not substantially meet the requirements，the PSCO should proceed to a more detailed inspection.

A.clean report
B.serious deficiencies
C.clear ground
D.detention report

单项选择题If a ship is proceeding towards the magnetic equator，the uncorrected deviation due to permanent magnetism（）.

A.increases
B.remains the same
C.decreases
D.is unimportant and may be neglected

单项选择题How does an icebreaker normally free a ship which has become beset while navigating independently?（）

A.By backing down the track and cutting out ice on either bow
B.By approaching from the stern and crossing ahead at an angle of 20°to 30°to the beset ship's course
C.By overtaking the beset ship，running ahead and then backing down the track to the beset vessel
D.By approaching the vessel from astern and towing the beset vessel stern first