Rule 19/Radar Plotting

Question 1

What MGN refers to Navigation in restricted Visibility?

Answer 1

MGN 369 (M+F)

Question 2

What determines the accuracy of the plot of a target on a RADAR display?

Answer 2

The accuracy and correct use of the feed inputs

Question 3

A RADAR in SEA stabilised mode will use what inputs?

Answer 3

STW and GYRO

Question 4

A RADAR in GROUND stabilised mode will use what inputs?

Answer 4

SOG and GYRO

Question 5

How do we determine whether the trails are true or relative?

Answer 5

True, Own vessel will have a trail (poo)
Relative, Own vessel will not

Question 6

How do we determine whether vectors are true or relative?

Answer 6

True, Own vessel will have a true vector from their heading marker
Relative, Own vessel will not

Question 7

In SEA stabilised mode, how do we determine the tidal set?

Answer 7

A-W will determine the tidal set, a the body of water we are floating on is moving PAST a fixed navigational mark

(In Ground stabilised, the mark will appear stationary, but our own ships vector will give an indication as to the tides affect on our course made good)

Question 8

Actions on encountering Restricted Visibility

Answer 8

Slow the vessel to a safe adapted speed, ME’s ready for manoeuvre, engage hand steering

Sound Fog Signal/Ensure NAV lights are on

Close WT/Fire Doors

Inform Master

Begin plotting/long range scanning

Post additional lookouts

Assess position on chart

Stop all noisy works on deck

Note in log

Question 9

What is ARPA?
What does it enable?

Answer 9

Automatic RADAR Plotting Aid

Plotting of at least 20 targets
Trial Manoeuvre

Question 10

What size vessels require ARPA?

Answer 10

Ships over 10000gt
Second radar must be fitted with ATA if not ARPA

Question 11

What is ATA, and what size vessels require it?

Answer 11

Automatic Tracking Aid
Ships over 500gt
Ships over 3000gt must have two radars with ATA

Question 12

What is EPA, and what size vessels require it?

Answer 12

Electronic Plotting Aid
Ships between 300gt and 500gt

Question 13

Is manual plotting still acceptable?

Answer 13

No, only for existing ships still complying with SOLAS V/74

Question 14

Speech given in exam when dealing with Plotting and RADAR

Answer 14

OA is a relative motion line, which when extended gives CPA and TCPA

If there is a ROC, or an unacceptable CPA, then I will require W, to complete the plot.

WO is Way of Own
WA is Way of Another (true course and speed)

I am required to take action, then if in restricted visibility under rule 19

Question 15

With regards to restricted visibility, which:
Convention outlines actions to be taken
MGN gives guidance
Procedures in board

Answer 15

ColRegs 1998
MGN369 / MGN 315 / MGN 379
SMS (ships nav policy) / BPG Checklist B giving guidance on Bridge Resource Management (BRM)