Raymarine LIGHTHOUSE 3 Advanced Operation Instructions page 354

• rate-of-turn too slow or too fast
Compass lock
Once you are satisfied with the compass accuracy, you can lock the setting to prevent the system
from completing a further automatic linearization in the future.
This feature is particularly useful for vessels in environments that are exposed to strong magnetic
disturbances on a regular basis (such as offshore wind farms or very busy rivers, for example). In
these situations it may be desirable to use the Compass lock feature to disable the continuous
linearization process, as the magnetic interference may build a heading error over time.
Note: The compass lock may be released at any time, to allow the compass continual monitoring
and adaptation to re-commence. This is particularly useful if planning a long voyage. The earth's
magnetic field will change significantly from one geographical location to another, and the
compass can continually compensate for the changes, ensuring you maintain accurate heading
data throughout the voyage.
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