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alarms may be silenced for some targets but will still remain active for other targets.
When an alarm is sounded, the display immediately shows the target that has triggered the
alarm. Pressing the
Mute
button silences the alarm and all subsequent alarms for that target
only. Other targets may still trigger alarms. The idea is that you have acknowledged the
target and are now aware of its presence and/or collision potential. The
AIS
WatchMate
will
continue to monitor and update the display for that target, but
unless you turn the alarm
back on for that target it will not cause any other alarms
.
To turn the alarm back on for a target, use the
Enable Alarms
from the target menu. The
display briefly shows whether alarms are muted or enabled for each target whenever the
Enable
or
Disable Alarms
menu item is selected.
If more than one target is simultaneously triggering alarms, then the highest priority target is
shown first. Once you have pressed the
Mute
button for that target, the next highest priority
target is immediately shown and the alarm sounds again. When you press the
Mute
button
for the last (or only) target with an alarm triggered, the display remains showing that target.
When an alarm is triggered for a target, the target is automatically displayed and the reason
for the alarm is blinking (eg.
RNG
for a guard alarm and
CPA
for a CPA alarm). The blinking
stops when the alarm is muted or the target is no longer triggering an alarm.
Guard Alarm
The simplest type of target alarm is the guard alarm. It is triggered whenever a target is
within range of the alarm setting. It works similar to a radar guard alarm. You select the
range for the alarm and if any vessel is currently within that range, in any direction around
you, the alarm is triggered.
When a guard range is selected, a guard alarm is only triggered for a target when it is
currently within the guard range and is not based on whether the target will enter the guard
range at some time in the future.
You can also select to have all targets trigger an alarm regardless of their range by setting
the guard alarm to “ALL” rather than a specific range. When this setting is enabled the alarm
will sound when data is first received for each target. This alarm setting is most useful
offshore or anywhere targets are expected to be encountered infrequently. It is used to notify
the user that an AIS target exists “out there” even if the target poses no collision risk.
When a guard alarm is triggered the target is immediately displayed. Press the
Mute
button
to silence the alarm. No further alarms will be triggered for this target. However, if you still
wish to have a subsequent CPA alarm for this target, use the
Enable
Alarms
menu item to
re-enable alarms for the target. When you re-enable alarms, the guard alarm is not sounded
again. Only subsequent CPA alarms will be re-enabled. The reason is you have been alerted
to the target's presence and acknowledged it but have now indicated you also would like to
have an alarm triggered if a collision risk exists.
Important note: Guard alarms will not be triggered if GPS information is unavailable
for your vessel.
Guard alarms which specify a range require GPS data for your vessel.
These alarms will not be triggered if GPS data is not available. However, if you set the guard
alarm to “ALL”, then the alarm will sound regardless of whether GPS data is available or not.
You can use this feature if you have not connected the
AIS
WatchMate
to a GPS but wish to
be alerted when targets are present.
This is the only alarm setting that will work when
GPS data for your vessel is not available.
CPA Alarm
A CPA alarm is triggered when a target meets the criteria you have established. When a
CPA alarm occurs, the target that caused the alarm is displayed. Press the
Mute
button to
silence the alarm. No further alarms will be triggered for this target. However, if you wish to
