TM 55-1905-223-24-14
o Magnetic compasses are important because they do not require power.
(2) Capabilities and Features.
o 0on the compass card, attached to the magnets, always points to
magnetic north.
o The vessel's heading is indicated by the alignment of the compass card
and the lubber's line.
b. Location and Description of Major Components. The Magnetic Compass System equipment (FIGURE 1-2)
consists of a binnacle containing a 7-1/2 inch Navy standard type reflector compass. The-binnacle is located on top of
the wheel house (FIGURE 1-3) with the reflector tube assembly extending down through the pilot house overhead for
viewing by the soldier at the helm.
(1) Binnacle. The binnacle (FIGURE 1-16, Sheet 1) consists of a pedestal mounted to the pilothouse
top by eight bolts through a bottom ring. Also included in the binnacle are the hood, quadrantal spheres and brackets,
rheostat, toggle switch, and access door. Located in the pilot house is the reflector tube assembly secured to the
overhead by a ceiling flange. Also in the pilot house is the reflector mirror housing containing the reflector mirror and
mirror adjusting knobs. FIGURE 1-16, Sheet 2 shows the flinders bar tube attached to the pedestal by two brackets and
with a cap. The pedestal houses the heeling magnet assembly and lens assembly. The hood houses the hood lamp and
covers the magnetic compass.
(2) Magnetic Compass. The magnetic compass (FIGURE 1-17) is a 7-1/2 inch reduced diameter dead
beat card in Navy standard type, silvered bowl graduated 0-360 degrees, under lighted. The compass is suspended by
bronze bearings in a gimbal ring mounted on spring suspension to reduce vibration.
c. Magnetic Compass Equipment Data. The following reference data applies to the magnetic compass
system:
Binnacle Power Input: 24 Vdc, single phase, 60 Hz.
d. Safety, Care and Handling. Safety precautions must be observed at all times while performing maintenance.
General WARNINGS and first-aid data appear in front of this manual. Review all safety information before
starting any task. Carefully read through an entire maintenance procedure before performing any j maintenance function.
Make sure the task can be done safely. All WARNINGS, CAUTIONS, and NOTES are of great importance to your safety
and the safety of the equipment.
(1) Keep Away From Live Circuits. Soldiers must at all times observe all safety regulations. Do not
replace components inside the equipment with power turned on. Under certain conditions, dangerous potentials may exist
when power is turned off. Always remove power at the source, and discharge or ground a circuit before touching it.
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