Nav Computer: Centre dot on TAS (155 kts), rotate to put wind direction (160šT) on HEADING index and mark wind on centre line 18kts below centre dot (over 137 kts).

Rotate to put track 305šT next to HEADING index; read drift (3š right (Stbd)) and rotate to put track (305š) under drift (3šStbd).   Drift has now changed to 4šStbd so put track 305š under 4šStbd.   On heading 301šT the drift 4šStbd will give the required track, 305šT and the groundspeed is under wind mark: 169 kts.