Chart Navigation & Plotting · Set & Drift — From DR and Fix
Your 1000 DR position and your simultaneous 1000 fix do not coincide: the fix lies 270°T, 2.0 NM from the DR. The last fix was at 0600. What is the set and drift?
- ASet 090°T, drift 0.5 knots
- BSet 270°T, drift 0.5 knots✓ Correct
- CSet 270°T, drift 2.0 knots
- DSet 090°T, drift 2.0 knots
Explanation
Set is the direction FROM the DR TO the fix (the current has carried the vessel to the fix), here 270°T. Drift is the displacement divided by elapsed time: 2.0 NM over 4 hours (0600 to 1000) = 0.5 knots.
Authority: Bowditch (Pub. No. 9), Current Sailing
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
- 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:
- Distance, Speed & Time
A vessel makes good 12 knots. How far does it travel in 20 minutes?
- Distance, Speed & Time
A vessel covers 9 nautical miles in 45 minutes. What is its speed?