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˚.