The Grand Fleet of the British Navy had taken substantial losses during the onset of the war. And as a result, the phrase "Britania Rules the Waves" had not exactly been repeated in some time. No, it was an era of German dominance, on the seas, on the lands, and in the skies.
And because of this, the British Navy had spent the last two years trying their darndest to come up with a solution to their current predicament. The mounting of QF 2 lb "Pom-Pom" maxims did little to help with this.
Sure, the torpedoes launched by the He-51 Seaplanes were a problem. But they could fly at high enough altitude to avoid 20mm rounds. And besides, that did not address the real problem with the damn near undetectable submarines which were lying in wait under the seas to attack British ships with Wolfpack tactics.