Depth charges and other anti-submarine systems appeared during World War I, but surface gunfire remained important because submarines often fought or were caught on the surface. A damaged submarine could lose the ability to dive, making the destroyer's ordinary guns part of its ASW toolkit. Destroyers also accumulated different operational lessons with the Harwich Force, the Grand Fleet, battlecruisers, and merchant convoys. Bringing those experiences together helped navies judge which escort capabilities worked and what interwar designs needed to improve.
Notable Point · 20:27-21:42
World War I gives destroyers several kinds of escort experience
Early anti-submarine work and service with striking forces, battle fleets, and merchant convoys gave navies different evidence about what destroyers needed to do.