Your vessel is participating in the Voluntary Observing Ship Program, you are preparing WS Form B-80 as seen in illustration D041NG below. One-half of the sky is covered with clouds, and the anemometer indicates that the apparent wind is from 340° relative at 14 knots. You are on course 307°T at 12.6 knots. How should you encode group Nddff?

Question

Accepted Answer

Option B: 42205. The Nddff group encodes cloud cover (N=5 for 4-5 oktas), wind direction (dd=22 for 220°), and wind speed (ff=05 knots). Using the vector triangle: True Wind = Apparent Wind + Ship's Motion. Calculating the resultant vector from 340° at 14kts and 307° at 12.6kts yields a true wind from 220° at 5 knots.