Chart Navigation & Plotting · Set & Drift — Fair Current
To make good a speed of advance of 12 knots with a 3-knot following (fair) current, the required speed through the water is:
- A15 knots
- B9 knots✓ Correct
- C12 knots
- D3 knots
Explanation
A fair current adds to speed over ground: STW + 3 = 12, so STW = 9 knots.
Authority: Bowditch (Pub. No. 9), Current Sailing
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