World War I reorganizes destroyers for fleet war

The Russo-Japanese War offered only a limited preview, while World War I made destroyers central to fleet, channel, and anti-submarine operations. Harwich Force supplied especially visible evidence through aggressive night fighting and demanding small-ship seamanship. Wartime growth also produced dedicated destroyer leaders able to fight opposing destroyers from an advantage. Early flotillas could contain more than twenty destroyers and several light cruisers, but experience favored smaller groups. A captain in a destroyer leader eventually commanded roughly eight destroyers with a small staff, giving more junior officers substantial command responsibilities. A three-division arrangement, with a commander's ship and two other destroyers in each division, was tried before the preference settled on two divisions of four. Groups of four suited operations and force generation while allowing the ships to work in pairs.