Boston Whaler 25 Guardian Series, Operation & Maintenance Manual

Page: 75 / 134

4-7
Boat Systems Section 4
Compass
Deviation
Your magnetic compass is located in line with the
helm station, below the operator’s line of sight so it can
be easily read during normal boat operation.
The location of your compass has been selected to
minimize deviation caused by other equipment
installed on the boat.
Magnets, ferrous metals, and
current-carrying devices are common causes of devia-
tion.
Periodically check the alignment of the compass to
verify that it is installed properly and compensated.
Compensation is the act of correcting for deviation.
Refer to the compass manufacturer’s literature for
detailed information about the compensation proce-
dure.
Variation
It is important to understand that magnetic compasses
point toward
magnetic north . There is a difference
between magnetic north and true north. That differ-
ence is called variation. Variation differs depending on
your geographical location and can be determined by
referring to a local chart.
Night Lighting
The internal red night operation light is connected to
the lighting circuit of the engine gauges. The compass
night light, like the engine gauge lights, is dimmed
using the dimmer switch on the helm station switch
panel.
!
WARNING
All magnetic compasses are subject to
magnetic interference, which can produce
errors called deviation. Compass deviation can
contribute to inaccurate course plotting and
position fixes, placing your crew, your boat,
and others at risk.