Prewar exercises assumed enemy aircraft would concentrate on capital ships and other major units, so destroyers were expected to fire their 4.7-inch mountings at relatively low angles. The scripted threat made the arrangement look adequate. In combat, aircraft attacked any reachable ship, exposing destroyers to direct attack in circumstances the exercises had discounted. The example shows how equipment can pass an exercise built around friendly assumptions and still fail against an enemy choosing its own targets.
Notable Point · 31:48-32:43
Destroyer anti-aircraft exercises conceal a wartime flaw
The Royal Navy's 4.7-inch destroyer mountings provide a second example of exercise assumptions masking the threats ships would meet in combat.