Pom-Pom barrage doctrine and the Swedish Bofors requirement

The Pom-Pom was developed around a visually aimed wall of fire: crews led the target and filled the air ahead of it with projectiles. Airships were among its original targets, presenting a large, relatively slow object to hit. Sweden wanted an ambush weapon for ships concealed during daylight, able to engage individual aircraft that approached their hiding places. That requirement differed from preparing a large fleet to meet mass raids. The Mediterranean comparison emphasizes larger German and Italian land-based aircraft, including Italian trimotors. Pacific attacks more often involved smaller single-engine aircraft, demanding greater precision in the area covered by the gunfire, although Japanese land-based bombers also attacked ships.