| NAVAL ORDNANCE AND GUNNERY, VOLUME 1 CHAPTER 8 SEMIAUTOMATIC WEAPONS |
| HOME INDEX Chapter 8 Semiautomatic Weapons A. General B. Five-inch 38-caliber assemblies C. Five-inch 54-caliber assembly |
| 8C1. General The 5”/54 mount Mark 39 is an enclosed, dual-purpose, semiautomatic, rapid-fire, tray-loading, base-ring type single gun mount. It is a mount resembling the 5”/38 caliber single enclosed mount. It differs, however, from that basic type in its elevation and train power drives, and its ammunition service. And its sights are like those of 5”/38 twin mounts. |
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| 8C2. Design development The 5”/54 caliber mount, shown in figure 8C1, is a design developed primarily for the USS Midway class carriers. It will also be installed on certain other new construction vessels. Installations on each Midway class ship consist of 9 port and 9 starboard mounts, placed outboard below the level of the flight deck. The mounts are supported on cylindrical foundation bulkheads similar to turret foundations. These foundations are structurally supported on sponsons extending from the ship’s hull, with sponson platforms mounted flush with the main deck. The foundation bulkhead forms the upper ammunition-handling room enclosure. |
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| 8C3. Mount arrangement The general design (see figs. 8C2 and 8C3) and functional arrangement of the 5”/54 caliber gun and mount are patterned after the 5”/38 caliber single and twin enclosed mounts. This mount has an enclosed gun room arrangement with shield, gun, slide, and hoists mounted on a base-ring type carriage above an ammunition-handling room. The carriage is supported and rotates on bearings on a conventional stand. Carriage and gun are arranged for empty-case ejection from the gun through chute and doors in the carriage overhang to the main deck level of the sponson. Gun room and handling room are weather-sealed and power-ventilated. 8C4. Elevating and training gears The power drives for elevating the gun and training the mount are separate high-speed all-electric amplidyne units (chapter 10 discusses the operation of amplidyne units) controlled by electric signals either from a remote computer (when in automatic) or from the local handwheel stations. The elevating and training gears are equipped for auxiliary manual drive. The elevating and training power-drive generating equipment is remotely located in the ship at the second platform. The limits of gun laying motion are from 10° depression to 85° elevation, with a maximum train of 190°. 8C5. Ammunition This gun uses semifixed ammunition consisting of a 70-pound projectile and a case assembly weighing 32 pounds. The powder charge itself weighs 18 pounds. The gun and its crew are capable of a sustained firing rate of about 15 to 18 rounds per minute. 8C6. Ballistic data The mount is designed for use against surface and airborne targets. The gun has a horizontal range of about 26,000 yards and a maximum vertical range of 49,000 feet. Initial velocity of service rounds is 2,650 feet per second. 8C7. Personnel A minimum crew of 16 men, 10 for the gun room and 6 for the handling room, is required for ammunition service, gun loading, gun laying, and sight operations. |