Chart Navigation & Plotting · Set & Drift — Estimated Position
Why is an estimated position (EP) generally considered more reliable than a dead-reckoning (DR) position?
- AThe EP applies the best estimate of set and drift to the DR, accounting for current and leeway✓ Correct
- BThe EP is plotted from celestial observations only
- CThe EP ignores current to avoid compounding errors
- DThe EP is always taken from GPS
Explanation
A DR position accounts only for ordered course and speed. An EP improves on it by applying the best available estimate of current set/drift (and leeway), so it better reflects the vessel's probable true position.
Authority: Bowditch (Pub. No. 9), dead reckoning and the estimated position
Practice the full Chart Navigation & Plotting bank
Free spaced-repetition quizzing across 2190 USCG exam questions — it schedules your reviews so the ones you miss come back until they stick.
Related Chart Navigation & Plotting questions
- Set & Drift — Estimated Position
An estimated position (EP) differs from a dead-reckoning (DR) position in that the EP also accounts for:
- Set & Drift — Estimated Position
From your 1200 DR, a current is known to set 180°T at 2.0 knots. Where is the 1400 estimated position relative to the 1400 DR?
- Chart Basics
On a Mercator chart, one nautical mile is measured using the:
- Chart Basics
The principal advantage of the Mercator projection for navigation is that:
- Chart Basics
Charted depths (soundings) on a U.S. chart are referenced to which tidal datum?
- Chart Basics
Vertical clearances of bridges and overhead cables on a U.S. chart are normally referenced to: