How does C. S. Forester use imagery in Lieutenant Hornblower?

Imagery:

"Lieutenant William Bush came on board H.M.S. Renown as she lay at the anchor in the Hamoaze and reported himself to the officer of the watch, who was a tall and rather gangling individual with hollow cheeks and a melancholy cast of countenance, whose uniform looked as if it had been put on in the dark and not readjusted since.

The young volunteer faced aft and screamed into the wind to make himself heard. From his station aft Bush saw the captain advance to the poop rail; Bush could see he was shaking with rage, the big nose pointing forward as though seeking a victim.