单项选择题
A ship under construction or major repair will acquire permanent magnetism due to（）while sitting stationary in the earth’s magnetic field.
A.hammering and jarring
B.vibration and pounding
C.varying magnetic fields
D.stable or permanent magnetism of the ship
相关考题
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单项选择题
When changing from a compass course to a true course you should apply（）.
A.variation
B.deviation
C.variation and deviation
D.a correction for the direction of current set -
单项选择题
When adjusting a magnetic compass using the fore-and-aft permanent magnets，you should（）.
A.use the magnets one at a time，putting one in one side and then one on the opposite side，one step higher
B.use the magnets in pairs，starting at the top，with trays at the highest point of travel
C.use the magnets in pairs，from the bottom up，with the trays at the lowest point of travel
D.fill all the trays with magnets，then remove them one-by-one until the deviation is removed -
单项选择题
When adjusting a magnetic compass for error，a deviation table should be made（）.
A.before correcting for any deviation
B.after correcting for variation
C.after adjusting the fore-and-aft and athwartships permanent magnets
D.before the quadrantal correctors are placed on the compass
