USCG Exam PracticeDead reckoning — DR plot maintenance
In confined waters, piloting is preferred over dead reckoning alone primarily because:
- A. DR cannot account for changes in compass variation in restricted channels
- ✓ Piloting uses landmarks, aids to navigation, and soundings that provide external position references where DR alone is insufficientCorrect
- C. Electronic navigation is always obstructed by terrain in confined waters
- D. Running fixes are more accurate than simultaneous fixes in restricted waters
Why B is correct
Bowditch Ch. 1 §103 states piloting is the primary method in confined waters where dead reckoning alone is insufficient. It relies on landmarks, aids to navigation, and soundings as external references. The source does not state electronic navigation is always obstructed, only that it may be.
Cited:Bowditch Ch. 1 §103