How does C.S. Forester use imagery in Hornblower and the Hotspur?

Imagery:

He kissed her; down at the water's edge there was the familiar rattle of oars on thwarts, and the sound of male voices, as his boat's crew perceived the two shadowy figures on the Hard. Maria heard those sounds as clearly as Hornblower did, and she quickly snatched away from him the cold lips she had raised to his.
"Good-bye, my angel."
There was nothing else to say now, nothing else to do; this was the end of this brief experience. He turned his back on Maria; he turned his back on peace and on civilian married life, and walked down towards war.

"Cargill was a man of thirty, red-faced and corpulent.."

The marine stood stiffly at attention, feet at an angle of forty five degrees, musket close in at his side, forefinger of the left hand along the seam of his trousers, neck rigid in its stock—so that, as Hornblower was not directly in front of him, he stared over Hornblower's shoulder.