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CANADIAN COAST GUARD AUXILIARY - PACIFIC RADAR PLOTTING 3 CANADIAN COAST GUARD AUXILIARY - PACIFIC 2008

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RADAR PLOTTING 3. 2008. CANADIAN COAST GUARD AUXILIARY - PACIFIC. End On Situation. Own vessel 050° at 10 knots 6 minute plot. (1) Find the course you are going, and draw a line for your course In the case of heads up , mark 000°. Own vessel 050° at 10 knots 6 minute plot. 12:00 O. - PowerPoint PPT Presentation

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No Slide TitleRADAR PLOTTING
2008
End On Situation
Own vessel 050° at 10 knots
6 minute plot
(1) Find the course you are going, and draw a line for your course
In the case of heads up , mark 000°
CANADIAN COAST GUARD AUXILIARY - PACIFIC
Own vessel 050° at 10 knots
6 minute plot
(2) Mark the first radar bearing and range of the target.
358º R x 2.5 nautical miles.
All bearings are R as they are relative to your vessel’s head.
Mark as "O“
Own vessel 050° at 10 knots
6 minute plot
(3) After 6 minutes mark the second radar bearing and range of the target.
359ºR x 0.77 nautical miles
Mark as “A”
Own vessel 050° at 10 knots
6 minute plot
(4) From "O" draw a line through "A" and carry the line well past the centre line on the screen
12:06 A
12:00 O
Own vessel 050° at 10 knots
6 minute plot
(5) Transfer your course line to "O" and pull the line down the sheet
12:06 A
12:00 O
Own vessel 050° at 10 knots
6 minute plot
(6a) Calculate own vessel distance in plot interval.
To use calculator scale, place right point of divider on 60 (right end of scale) and left point on own vessel speed (10 knots).
12:06 A
12:00 O
Own vessel 050° at 10 knots
6 minute plot
(6b) Move the dividers at this setting, and place right point on the plot interval (6 minutes)
The number under the left point of the dividers will indicate the distance gone in the plot interval. (1 nautical mile).
6 min @ 10 knots = 1.0nm.
12:06 A
12:00 O
Own vessel 050° at 10 knots
6 minute plot
(6c) Lay down 1 nautical mile on the plot, on own course vector from “O”.
Mark bottom end “W”
Own vessel 050° at 10 knots
6 minute plot
(7a) Connect “W” with “A”. “W” to “A” represents target course and distance travelled in the plot interval.
174°R @0.75 nautical miles
To convert this into speed, place right point of dividers on plot interval (6 minutes) and the left point on distance travelled in that time (0.75 nm)
12:06 A
Own vessel 050° at 10 knots
6 minute plot
(7b) Move dividers so that right point is on 60 (right hand end of scale).
The reading under the left point of the dividers will be the vessel’s speed in knots.
7.5 knots
12:06 A
Own vessel 050° at 10 knots
6 minute plot
(8) Where the line through “O” and “A” passes closest to the centre of the plot is the Closest Point of Approach (CPA)
In this case very close to starboard - scraping the tube.
12:06 A
Own vessel 050° at 10 knots
6 minute plot
(9) The Time to Closest Point of Approach (TCPA) is at the tangent point. OA is 6 minutes.
A to TCPA works out at 2.5 minutes = 12:08:30
12:06 A
Results
In this case, providing neither you nor the target vessel alter course or speed:
the target vessel is proceeding at 050° + 174° = 224°C at 7.5 knots
CPA is at 12:08:30 with a collision
CANADIAN COAST GUARD AUXILIARY - PACIFIC
Results – Clear Visibility
In clear visibility, you are to assume you in an end on situation and therefore must take action to avoid collision. Whilst the other could be taken as a crossing vessel, it is safer to assume an end on situation.
There is a risk of collision, and therefore you must make a bold alteration to starboard.
The other vessel should do likewise.
CANADIAN COAST GUARD AUXILIARY - PACIFIC
Results – Restricted Visibility
In restricted visibility, you are required to take action.
As in clear weather, a broad alteration of course to starboard is the best action, carefully monitoring the actions of the other vessel.
A 90 degree starboard alteration would be best in this case.
CANADIAN COAST GUARD AUXILIARY - PACIFIC
End On Situation
End On Situation
If however at 1206 you acknowledge the other vessel is on a steady bearing, you can stop and assess the situation.
The plot will then change to:
CANADIAN COAST GUARD AUXILIARY - PACIFIC
Own vessel 050° at 10 knots
6 minute plot
12:06 A
12:00 O
In this case stopping will only gain you thinking time, but does not prevent a close quarters situation.
You will need to make a 90° alteration of course to starboard and increase speed to comply with rule 14.