Reading "A Company of Tanks", I found a reference to "swinging" the tank to adjust it's compass. Would I be right in assuming that this is the same or similar to the way boats adjust their compasses?
It would appear so, but I don't think it involves physically swinging the Tank - it seems to mean calibrating the compass, like synchronising watches.
The process of checking for magnetic deviation is known as "swinging" the compass and is fairly straightforward. To swing a compass, the compass is pointed in a direction known to be magnetic north. The difference between the compass reading and what it should read is then recorded, in degrees east or west.
Correcting for magnetic deviation is similar to correcting for magnetic variation. Once you have a magnetic course, you add or subtract the appropriate error to get a compass course. When going from magnetic course to a compass course, errors labeled west are added and east are subtracted. Usually these calculations are done on a chart with the magnetic course labeled "M," the deviation labeled "D," and the compass course labeled "C."
Does that make sense?
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It would appear so, but I don't think it involves physically swinging the Tank - it seems to mean calibrating the compass, like synchronising watches.
The process of checking for magnetic deviation is known as "swinging" the compass and is fairly straightforward. To swing a compass, the compass is pointed in a direction known to be magnetic north. The difference between the compass reading and what it should read is then recorded, in degrees east or west.
Correcting for magnetic deviation is similar to correcting for magnetic variation. Once you have a magnetic course, you add or subtract the appropriate error to get a compass course. When going from magnetic course to a compass course, errors labeled west are added and east are subtracted. Usually these calculations are done on a chart with the magnetic course labeled "M," the deviation labeled "D," and the compass course labeled "C."
Does that make sense?
Makes a lot of sense. I wasn't sure how swinging worked but I had a rough guess that it would be somewhat like the way you mentioned and I Googled it. Got a U.S.C.G. pdf which describes how it is done with a boat and figured the principle is the same, you just don't have to wait for calm waters with a tank(except in Ypres).
I would agree Mark - the process of swinging the compass on a tank to reduce the amount of compass deviation would likely be similar to that on a boat. Deviation is the difference between the actual direction to the magnetic north pole and the direction which the compass indicates as north, and occurs as a result of the interaction between the Earth's magnetic field and the magnetic field inherent to the tank (likely considerable due to its steel construction and electrical equipment). It would vary with the orientation of the tank, and between seemingly identical tanks. To eliminate as much deviation as possible from a compass, it would be necessary to mount it in its usual operating position within the tank, start the tank up, and then turn the tank in various known directions determined from a map. The amount and direction of deviation for each orientation could then be directly measured, and reduced as much as possible by the use of compensating magnets. Any residual deviation would be recorded in a table which would be unique to that tank.
