USCG Exam PracticeDead reckoning — DR plot maintenance
Which of the following is NOT listed in Bowditch as a source of navigational error that can affect DR plot accuracy?
- A. Plotting error
- B. Instrument error
- C. Computation error
- ✓ Magnetic variation errorCorrect
Why D is correct
Bowditch Ch. 23 §2301 lists instrument error, observation error, plotting error, computation error, and the assumption that the vessel has held the planned course as sources of navigational error. Magnetic variation error is not enumerated in the supplied source chunk.
Cited:Bowditch Ch. 23 §2301