At 1239 your GPS indicates a position of LAT...

Question 1 of 31048fork_061fb68f9d0e4c89873

At 1239 your GPS indicates a position of LAT 36°55.2'N, LONG 75°33.1'W. You are on course 281° per standard magnetic compass at a speed of 9.2 knots. At 1318 your GPS indicates your position as LAT 36°54.8'N, LONG 75°39.8'W. What were the set and drift?

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Question 1 of 31048

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🔍 Key Concepts

• Set and drift: compare the vessel’s actual GPS displacement with the distance and direction it would make good through the water. • Compass-to-true conversion: use the deviation table at the magnetic heading corresponding to the stated compass course, then account for the stated 9°W variation. • Vector difference: resolve the actual movement and the estimated through-water run into north/east components, then find the current vector.

💭 Think About

• From 1239 to 1318, what is the elapsed time, and what distance would the vessel cover at 9.2 knots on its corrected true course? • Plot the two GPS positions to determine the actual course and distance made good; how does that ground-motion vector differ from the through-water vector? • For the resulting current vector, which direction is it flowing toward, and what is its speed in knots?

✅ Before You Answer

• Use the deviation appropriate to a magnetic heading near the stated 281° compass course; do not mistake the compass course for true course. • Keep variation and deviation signs consistent when converting compass course to true, and use the elapsed interval in hours for both distance calculations. • Report set as the direction the current flows toward and drift as speed; check the plotted/vector result against the choices.