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Closest point of
approach (CPA)
The CPA is the closest a target will come to your vessel if both your
vessel and the target maintain their existing course and speed. It is
displayed in nautical miles to the nearest tenth or hundredth. As
either your vessel or the target changes its course or speed, the
CPA (along with all other computed data) is automatically
recomputed and redisplayed.
Time until CPA (TCPA) This is the amount of time until the CPA will occur. It indicates how
much time is available before the two vessels will reach their nearest
distance to each other. It is displayed in minutes and seconds or just
minutes if the time exceeds one hour.
The
AIS
WatchMate
automatically updates these computed values whenever new information
is received from a target and also whenever your vessel's position, speed, or course
changes. The information displayed is always the most up-to-date available but because the
AIS and GPS systems do not guarantee the frequency of updates from each vessel it can be
inaccurate and can become further inaccurate as time progresses without continuous
updates from both vessels.
Always check to see how long it has been since an update was received from a vessel
when relying on this information, particularly in close situations.
You do this by
examining the “age” of the target. See the target display section for more details.
The AIS system also includes messages broadcast from other vessels and shore stations
which may be used to send navigation warnings, weather information, etc. The
AIS
WatchMate
displays this information on the
messages
page and by default is configured
to sound an alert when a message is received.
We are always interested in your suggestions, comments, ideas, and criticisms. We
continuously strive to improve our products and would greatly enjoy hearing from you.
Please contact us through our website
www.vespermarine.com
or
via e-mail to
.
Important Information
Before using the
AIS
WatchMate
, it is important that you read and fully understand this
owner's manual and installation instructions.
Although more vessels continue to install AIS transponders it is important to remember that
not all vessels carry AIS transponders.
The
AIS
WatchMate
can only display information
received from properly equipped and operated vessels. In addition, the
AIS
WatchMate
relies
on the accuracy of the GPS system. A failure or compromised operation of either of these
systems will reflect on the accuracy of the data displayed and alarms triggered by the
AIS
WatchMate
.
