USCG Exam PracticeCourse to steer to compensate for current
A navigator plots a DR position and an EP for the same time. The EP is displaced 1.5 miles at 270°T from the DR position. The vessel then obtains a fix at that time and finds the actual position coincides with the EP. What does this confirm about the current during that run?
- A. The current had no effect because the fix agrees with the DR position
- ✓ The current set was 270°T and its drift, over the elapsed time, produced 1.5 miles of displacementCorrect
- C. The current set was 090°T and its drift produced 1.5 miles of displacement
- D. The DR plot was in error because a fix should always agree with the DR position, not the EP
Why B is correct
Bowditch Ch. 8 §803 defines the EP as the DR position corrected by laying off the current's set and drift for the elapsed time. If the fix coincides with the EP, the estimated current was accurate: set 270°T with a total displacement of 1.5 miles over the elapsed time confirms the current was flowing toward 270°T. Option C reverses the set; options A and D misstate the relationship between fixes, DR positions, and EPs.