152 seamanship secrets
Find the time in minutes to the CPA:
3.4 miles at 10 knots = 20 minutes
1346 hours + 20 minutes = 1406
Label the time next to the CPA mark. Label the CPA mark 1406.- Track the target until it is past the CPA. Get a new relative bearing to the
target with your EBL (make sure to coordinate with the helm). Convert this
to a magnetic bearing and step back outside. Track the target by taking drift
bearings every minute until the target reaches the CPA bearing: 331 degrees
magnetic. Check the scope to make sure the target keeps tracking down the
DRM line.
Situation Analysis
Th e contact will cross your bow from right to left. You are the give-way vessel.
Unless he changes course and/or speed, he will clear your vessel by 1.5 miles.
Action to Avoid a Collision
To open the CPA farther, you must slow down, stop, or turn to the right by at
least 60 degrees. Make the course change decisive so the other vessel has no
doubt as to what you are doing.
Continue to track the vessel by radar and visual means. Use the handbear-
ing compass between plots to determine the bearing drift. As long as the target
keeps drift ing to the left , risk of collision does not exist.