Convert the relative wind to apparent
wind by plotting rw 040˚ relative to ship’s head which results in a true
direction of 280˚T .
Plot the apparent wind vector (reciprocal of 280˚T, 30 knots)
from the end of the vector er.
Label the end of the vector w.
The resultant vector
ew is the true wind vector of 135˚, 20 knots (wind’s course and speed).
The true
wind, therefore, is from 315˚.