My granfather served as an officer in the British Navy during WWI. He
spent much of the war aboard a class of ships called "Destroyer
Escorts" and protected convoys in the English Channel. According to his
journal he kept during those years, there were always mixed emotions
when they would sight a periscope
betraying the presence a German U-boat in the area. Grandpa's boat has
equipped with depth charges, and it would steam over to the sighting
and try to destroy or at least drive off the submarine.

The crew were always a bit apprehensive about the combat situation, of
course, but the bright side was that the ship's mess crew would appear
on deck with long handled nets and scoop up the fish that were killed
or stunned by the depth charges. Everyone could look forward to fresh
fish for dinner.