Navigation General · Currents
A vessel is steering 180°T at 10 knots through the water. A current sets 090°T at 3 knots. Using the current triangle, the SMG is approximately:
- A10.0 knots
- B13.0 knots
- C10.4 knots✓ Correct
- D7.0 knots
Explanation
The vessel moves south at 10 kts; current pushes east at 3 kts. These vectors are perpendicular. SMG = √(10² + 3²) = √(100 + 9) = √109 ≈ 10.4 knots. The CMG will be slightly east of south.
Authority: Bowditch (Pub. 9), Ch. 7
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