Hunter-killer helicopter pairs reveal the escort group's ASW arithmetic

ASW helicopters work best in hunter-killer pairs, with one aircraft fixing the submarine while the other attacks, much as paired corvettes divided the work during World War II. General-purpose destroyers should lead the hunt while the aviation ship and guided-missile destroyers coordinate from farther back. Providing one airborne pair for each of five general-purpose destroyers means ten helicopters flying, which could require twenty to thirty aircraft to sustain availability. Five destroyers carrying two helicopters each supply ten aircraft, while Hyuga adds as many as twenty-four, or about eighteen with larger helicopters. Helicopters aboard an accompanying Atago or Maya add further capacity, although Kongo lacks an embarked helicopter hangar. Regularly operating around half of that wartime strength would develop the experience needed to sustain the larger screen.