USCG Exam PracticeRunning fix from a single object
A navigator plots a running fix using two bearings to a single lighthouse taken 12 minutes apart at 8 knots. After plotting the running fix, the navigator should:
- A. Accept the running fix as equivalent in accuracy to a simultaneous two-LOP fix
- ✓ Check the running fix against subsequent fixes as soon as possible to account for cumulative navigational errorsCorrect
- C. Discard the running fix because a single object cannot produce a valid position
- D. Replace the running fix with the DR position because the DR is more reliable over short intervals
Why B is correct
Bowditch Ch. 23 §2301 states that cumulative errors must be checked against fixes whenever possible. Because the running fix is less accurate than a simultaneous fix (Bowditch Ch. 7 §702), the navigator must verify it against subsequent observations.