Chapter I

In July 1945, a scant three weeks before the end of World War II, the ships of the United States Fleet bristled with 87,919 gun assemblies, ranging in size from the light weight caliber .50 AA Machine Gun to the massive 16"/50 armored 3 gun turret which weighed as much as a single destroyer. The merchant fleet, in addition, mounted 48,446 antiaircraft and double purpose guns. The total firepower of the combined fleets aggregated 4,500 tons per 15-second period--35% on Navy combatant ships, 37% on other Navy vessels, and 28% on merchant ships. This represented an 11-fold increase over the mid-1940 firepower of our "one ocean Navy" which approximated 411 tons of projectiles for the 15-second period. In building up the Navy's terrific firing power during these five years there were involved infinite tasks of design, manufacture, procurement, and maintenance.[1]

During the early years of the war primary emphasis was placed upon the rapid production of existing types of anti-aircraft and antisubmarine guns. For this reason most of the design changes effected no improvement in performance



but were solely for the purpose of speeding production. Once a satisfactory rate was attained investigations were shifted to performance problems.[2] Projects for increasing the rate of fire also had high priority. Improved ammunition handling equipment for new 16"/50's, 16"/45's, and 12"/50's did much to increase the fire of these guns over their original counterparts. High hopes for the future were held for the 5"/54's, 6"/47 DP, and 8"/55 rapid fire guns, although at the end of the war they had not been in service. Because of the high priority of the above projects it was not until shortly before the end of the war that serious efforts were made to increase projectile velocity. These investigations were just getting under way in August 1945 but were to be continued as a postwar project.[3]

The most significant trend was the rapid increase in the antiaircraft batteries on combatant ships. At the beginning of the emergency 1.1", .50, and .30 caliber machine guns were the Navy's only protection against close flying aircraft and dive bombers.[4] The realization that these batteries were



obsolescent in quality and wholly inadequate in quantity gave added impetus to the Bureau's program for modernizing the antiaircraft armament of the Fleet, a program which was well under way at the time of Pearl Harbor. The small caliber guns were replaced rapidly by 20mm and 40mm batteries. The rates of production were stepped up on the excellent 5"/38 dual purpose gun, first issued to the service in January 1955, and an improved version of the 3"/50. Rapid production together with continuing improvements on these guns and their associated equipment gave the U.S. Navy qualitative and quantity superiority in antiaircraft defense over foreign navies, and particularly those of our enemies.

The antiaircraft guns were mounted aboard combatant ships in such quantities that ultimately only weight and space considerations became limiting factors. When those limits were reached, certain materials already mounted on the topsides were removed to make more top-weight carrying capacity available for more antiaircraft guns. The larger fighting ships--battleships, aircraft carriers, and cruisers which were already bristling with antiaircraft armament by the beginning of 1943, had by the end of that year



increased even further the number of guns carried. One of the newer battleships was capable of hurling into the sky from its antiaircraft battery alone a weight of explosive projectiles amounting to over 10,000 pounds in fifteen seconds of fire. And the battleships existing in December 1941 had by the end of 1943 increased the weight-throwing capacity of their close-in antiaircraft batteries by ratios varying between 600 and 1200 per cent.



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Transcribed and formatted by Thomas Wildenberg, HyperWar Foundation