[单选题]Depths in the routes (Malacca and Singapore Straits) vary between 20 m and about 23 m but there are many areas of sandwaves and depths are liable to change. The statement infers that ______.
[单选题]When a feature whose characteristics or descriptions remain unchanged is to be shifted to small distance(s), ______ command is used on a chart.
[单选题]When action to avoid a close quarters situation is taken，a course change alone may be the most effective action provided that ______.
[单选题]Which is a weekly publication advising mariners of important matters affecting navigational safety?
[单选题]From ________ the information concerning the tons per inch or centimeter immersion of a vessel shall be usually found．
[单选题]The fire and boat drills for a cargo ship should be ______ once a month under normal conditions．
[单选题]If the rotation for this vessel is Felixstowe, Antwerp, Le Havre, Hamburg and Rotterdam. The container for Rotterdam is right at the ____________of the heap.