Magnetic Compass Flashcards
What is the basic principle of the magnetic compass?
Magnetic materials of the same polarity repel each other and those of opposites attract
The permeant magnetism of a vessel may change in strength due to?
Major structural repair
How many degrees on a magnetic compass card?
360
What is the lubber’s line?
Indicates the vessels heading
What is the most important feature of the material used for making the binnacle of a standard magnetic compass?
that it is nonmagnetic
What should you do when a magnetic compass is not used for a prolonged period of time?
shielded from direct sunlight
The magnetic compass error which changes with the geographical location of your vessel is?
variation
Variation in a compass is caused by?
Magnetism from the earth’s magnetic field
Deviation changes with?
change in heading
The error in a magnetic compass caused by the vessel’s magnetism is called?
deviation
What is used to reduce the effect of deviation?
magnets in the binnacles of magnetic compasses
When changing a compass course to true course you should apply?
Variation and deviation
Compass error is equal to?
the combined variation and deviation
If the magnetic heading is greater than the compass heading then the deviation is?
east
Difference between magnetic heading and compass heading is called?
deviation
