USCG Exam PracticeDead reckoning — DR plot maintenance
Which of the following is a source of navigational error that accumulates and must be checked against fixes whenever possible?
- A. Compass deviation and variation only
- B. Set and drift only
- ✓ Instrument error, observation error, plotting error, computation error, and the assumption of steady courseCorrect
- D. The difference between course steered and course made good
Why C is correct
Bowditch Ch. 23 §2301 identifies instrument error, observation error, plotting error, computation error, and the assumption that the vessel held the planned course as sources of cumulative navigational error. Set and drift (option A) and course error (option D) are effects, not the enumerated error sources in §2301.
Cited:Bowditch Ch. 23 §2301