"NOT THINKING OF DEATH" is centered largely around the prewar experiences of a retired Royal Navy submariner, Rufus Chalk. The novel is largely told in "flashbacks." Rufus and his friend, Dymock, ex-naval classmates, are in training for command slots in one of the submarine flotillas. Dymock has a reputation as a playboy and ladies' man. So when he "steals" Chalk's brother's girlfriend away, Rufus' friendship with Dymock becomes strained.
There is also an incident in the novel related to an actual submarine accident which had taken place during service acceptance trials in 1939. Rufus and Dymock are both involved in this incident, and the results are tragic.
"NOT THINKING OF DEATH" was a good novel, notwithstanding the occasional thickness of naval jargon. The jargon shouldn't deter the reader from enjoying this novel. The jargon gives credibility to the novel. There is also wartime action, which lends added drama to the narrative.
On the whole, "NOT THINKING OF DEATH," while not on the scale of "THE CRUEL SEA," is a good novel. Read it at your leisure.