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.

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

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