TMQ Bosun-AP9, Operation And Installation Manual

Page: 24 / 63

TMQ Bosun - AP9 Rev1 (935) Page 24 16/06/2003
sensor is preferred for steel hull vessels provided a suitably compensated
compass is fitted to the vessel.
Installing a Magnetic Sensor Unit (Fluxgate)(COMMAG)
The compass unit should be treated carefully as the internal gimbals can be
broken if dropped. Remove any internal packing before use.
The position of this compass is the most important item in the installation
of the autopilot. Good course holding depends on the compass being free
from magnetic interference.
As this compass has no moving card, it is not necessary for the compass to
be mounted low in the vessel. This is usually a place of high magnetic
interference and should be avoided. However, a position of severe roll
such as the top of a mast should also be avoided.
The compass need not be mounted in a weatherproof position. The
compass can be mounted on top of a flat surface, on a bulkhead or from the
deck head. Check other side of bulkhead for materials, which may cause
magnetic interference.
Interference from any iron or steel can cause malfunction of the compass
unit. To prevent this occurring a minimum distance of 1 meter (3 feet)
should be kept from any steel or other ferromagnetic materials. This
includes speakers and radios with internal speakers.
Fasten the compass bracket with non-magnetic screws. The compass must
be mounted in a near vertical position. See also the diagram "Fluxgate
Compass Mounting Options".