DETERMINE THE NEW CPA WHEN OWN SHIP CHANGES COURSE
1. Parallel own ship's new course line from the center of the plotting sheet to point (e) and draw a line from (e) in the same direction as the new course.
2. Transfer own ship's original distance run (e-r) to this line and label the head of this vector (r').
3. Draw the NRM from point (r') to point (m).
4. Parallel the NRM to (MX). From (MX) draw the NRML in the same direction as the NRM.
5. Drop a perpendicular from the center to the NRML for the new CPA.
DETERMINE THE NEW CPA, WHEN OWN SHIP CHANGES SPEED
1. Calculate own ship's new distance run using the new speed and the time interval between the contact's first and last positions.
2. Lay off this new distance run. from point (e) along our original true course vector (e-r) and label the head of this new distance run (r').
3. Follow the same procedures as in steps 3,4 and 5 above to find the new CPA.
