What are some metaphors in the cay?

The novel opens on a metaphorical image. The opening line is one single sentence and it is set apart as a self-contained paragraph. What follows next is descriptive prose that is mostly free of any figurative language and simply gets down to the brass tacks. It is easy to imagine an editor existing somewhere who advise cutting the opening line and starting out the book by diving right into the descriptive exposition. To do so would be literary crime:

“Like silent, hungry sharks that swim in the darkness of the sea, the German submarines arrived in the middle of the night.”