35
RADAR OPERATION
H
H
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d
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-
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S
S
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R
R
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r
r
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In the following screen captures from a SINS Radar display, we will show a vessel progression on the radar scope for determining a
head-on
situation. Your
position is the white cross in the middle of the screen. You are on a course of 000°T. You are underway but maintaining station (drifting). You are in a head-on
situation with the other vessel. The white arrow represents the relative motion line (RML) line for the vessels. The white arrow showing the RML will not be
indicated on the radar scope.
(4 images total)
3
4
Three minutes later, acquire the contact again and Mark as
"M3" and put time in minutes acquired. The first and second
mark can still be faintly seen. The first, second, and third
mark will give you a better idea of the RML of the contact.
This RML indicates a contact that is in a head-on situation
with your vessel.
Three minutes later, acquire the contact again and Mark as
"M4" and put time in minutes acquired. The first, second, and
third mark can still be faintly seen. The RML from M1 to M4
will give you a very good idea of the RML of the contact. This
RML indicates a contact that is meeting your vessel head-on.
This is also a constant bearing decreasing range (CBDR)
situation. Speed and course changes will have to be made to
avoid collision.
