Chart Navigation & Plotting · Speed-Time-Distance
A vessel covers the distance between two buoys 1.5 NM apart in 6 minutes. Her speed is:
- A10 knots
- B12 knots
- C9 knots
- D15 knots✓ Correct
Explanation
The 'three-minute rule' and its 6-minute cousin: distance in 6 minutes × 10 = speed in knots. 1.5 × 10 = 15 knots. (60·D = S·T → S = 60 × 1.5 / 6 = 15.)
Authority: Bowditch, American Practical Navigator (Pub. 9)
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
- Speed-Time-Distance
A vessel makes good 18 nautical miles in 1 hour 12 minutes. What is her speed over the ground?
- Speed-Time-Distance
Steaming at 12 knots, how long does it take to run 30 nautical miles?
- Speed-Time-Distance
You run for 40 minutes at 9 knots. How far have you traveled?
- Speed-Time-Distance
Using the three-minute rule, a vessel travels 600 yards in 3 minutes. Her speed is approximately:
- Speed-Time-Distance
Required speed of advance: you must cover 96 NM and arrive in 8 hours. The SOA required is:
- Speed-Time-Distance
A vessel steams at 12 knots for 2 hours 30 minutes. The distance run is: