8-inch/55-caliber gun
Introduction The rounded roofs of early Mark 9 twin and triple turrets of  and  with the later turrets of  on the right.The '''8"/55 caliber gun''' (spoken "eight-inch-fifty-five-caliber") formed the main battery of United States Navy heavy cruisers and two early aircraft carriers. United States naval gun terminology indicates the gun barrel had an internal diameter of 8 inches (203 mm), and the barrel was 55 calibers long (barrel length is 8 inch × 55 = 440 inches or 36.6 feet or 11 meters).
Mark 9 These built-up guns weighed about 30 tons including a liner, tube, jacket, and five hoops. A down-swing Welin breech block was closed by compressed air from the gas ejector system. Loading with two silk bags each containing   of smokeless powder gave a  projectile a velocity of 2800 feet per second (853 m/s). Range was 18 miles  at the maximum elevation of 41 degrees.
Mark 12 These simplified built-up guns eliminated hoops to reduce weight to 17 tons. The breech mechanism was similar and loading two silk bags each containing 43 pounds (20 kg) of smokeless powder gave a 335-pound (152 kg) projectile a velocity of 2500 feet per second (760 m/s). Each gun could fire about four rounds per minute. Maximum range was  at the maximum elevation of 41 degrees.
Mark 14 These guns were similar to Mark 9, with the same shell weight and maximum range, with a smaller chamber and rifling twist increased from 1 in 35 to 1 in 25 in a chromium-plated bore.
Mark 15 These guns were similar to Mark 12, with the same shell weight and maximum range, with the smaller chamber of the Mark 14 gun. Useful life expectancy was 715 effective full charges (EFC) per liner.
Mark 16 These self-loading guns with lined monobloc construction and vertical sliding breech blocks weighed about 20 tons. Semi-fixed ammunition (projectile and powder case handled separately) with 78 pounds (35 kg) of smokeless powder gave a 335-pound (152 kg) projectile a velocity of 2500 feet per second (760 m/s). Each gun could fire about ten rounds per minute. Useful life expectancy was 780 Effective Full Charges per liner. Range was 17 miles (27 kilometers) at the maximum elevation of 41 degrees. This gun was modified for the experimental Major Caliber Lightweight Gun.
Coast defense use The eight twin turrets of  and  were removed in early 1942 during refits at Pearl Harbor. The turrets were turned over to the United States Army Coast Artillery Corps and remounted as coastal artillery on Oahu. Four two-turret batteries were established at Salt Lake near Aliamanu Crater (Battery Salt Lake, later Battery Burgess), Wiliwilinui Ridge Military Reservation (Battery Wilridge, later Battery Kirkpatrick), Opaeula Military Reservation (Battery Opaeula, later Battery Riggs), and Brodie Camp Military Reservation (Battery Brodie, later Battery George Ricker). After the war, all of the guns and turrets were scrapped in 1948, along with almost all other US coast artillery.One of s main battery 8 inch 55 caliber gun turrets (Turret No. 2) damaged in a kamikaze attack on January 5, 1945, was removed and taken to the Nevada Test Site and converted into a rotating radiation detector, to collect data on nuclear tests.
Ships mounting 8"/55 caliber guns The heavy cruiser  fires her 8"/55 caliber Mark 15 guns at Chinese troops threatening the evacuation of United Nations troops from Hungnam, North Korea, in December 1950 during the Korean War.The heavy cruiser s forward 8"/55-caliber guns fire at enemy targets ashore in North Vietnam in October 1966 during the Vietnam War. * 2  (c. 1921 – 1925) aircraft carriers:** , *** Mk 9 guns in four 190-ton twin turrets*** removed in 1942 and added to Oahu coast defenses* 2  (c. 1927) heavy cruisers:** , *** Mk 9 (later Mk 14) guns in two 190-ton twin turrets and two 250-ton triple turrets* 6  (c. 1928) heavy cruisers:** 2 of 6: , *** Mk 9 guns in three 250-ton triple turrets*** ''Houston'' was sunk in March 1942, ''Chicago'' was sunk in January 1943** 4 of 6: , , , *** Mk 9 (later Mk 14) guns in three 250-ton triple turrets* 2  (c. 1930) heavy cruisers:** , *** Mk 9 (later Mk 14) guns in three 250-ton triple turrets* 7  (c. 1931) heavy cruisers:** 3 of 7: 294 ton triple turrets*** : Mk 9 guns (sunk in 08/1942)*** : Mk 9 (later Mk 14) guns*** : Mk 9 (later Mk 15) guns** 4 of 7: , , , *** Mk 12 guns in three 250-ton triple turrets* ** Mk 12 guns in three 314-ton triple turrets* 14  (c. 1941) heavy cruisers:** 1 of 14: *** Mk 12 guns in three 300-ton triple turrets** 13 of 14: , , , , , , , , , , , , *** Mk 15 guns in three 300-ton triple turrets* 3  (c. 1944) heavy cruisers:** , ,  *** Mk 15 guns in three 300-ton triple turrets* 3  (c. 1945) heavy cruisers:** , , *** Mk 16 guns in three 450-ton triple turrets* 1 ex-: ** Mk 16 gun in one 86-ton single automatic mount 8"/55 caliber Mark 71 gun installationShipGun InstallationMk 9 guns in four 190-ton twin turretsMk 9 guns in four 190-ton twin turretsMk 9 (later Mk 14) guns in two 190-ton twin turrets and two 250-ton triple turretsMk 9 (later Mk 14) guns in two 190-ton twin turrets and two 250-ton triple turretsMk 9 (later Mk 14) guns in three 250-ton triple turretsMk 9 (later Mk 14) guns in three 250-ton triple turretsMk 9 (later Mk 14) guns in three 250-ton triple turretsMk 9 guns in three 250-ton triple turretsMk 9 guns in three 250-ton triple turretsMk 9 (later Mk 14) guns in three 250-ton triple turretsMk 9 (later Mk 14) guns in three 294-ton triple turretsMk 9 (later Mk 14) guns in three 250-ton triple turretsMk 9 guns in three 294-ton triple turretsMk 9 (later Mk 14) guns in three 250-ton triple turretsMk 9 (later Mk 15) guns in three 294-ton triple turretsMk 12 guns in three 250-ton triple turretsMk 12 guns in three 250-ton triple turretsMk 12 guns in three 250-ton triple turretsMk 12 guns in three 250-ton triple turretsMk 12 guns in three 314-ton triple turretsMk 12 guns in three 300-ton triple turrets CAG-1Mk 15 guns in three 300-ton triple turrets  CAG-2Mk 15 guns in three 300-ton triple turrets Mk 15 guns in three 300-ton triple turretsMk 15 guns in three 300-ton triple turrets Mk 15 guns in three 300-ton triple turrets Mk 15 guns in three 300-ton triple turretsMk 15 guns in three 300-ton triple turretsMk 15 guns in three 300-ton triple turretsMk 15 guns in three 300-ton triple turrets Mk 15 guns in three 300-ton triple turrets Mk 15 guns in three 300-ton triple turrets Mk 15 guns in three 300-ton triple turrets Mk 15 guns in three 300-ton triple turretsMk 15 guns in three 300-ton triple turretsMk 16 guns in three 450-ton triple turrets Mk 15 guns in three 300-ton triple turretsMk 15 guns in three 300-ton triple turretsMk 16 guns in three 450-ton triple turretsMk 16 guns in three 450-ton triple turretsMk 16 gun in one 86-ton single automatic mount (8"/55 caliber Mark 71 gun installation)
See also *8"/55 caliber Mark 71 gun 1970s US experimental program===Weapons of comparable role, performance and era===*203mm/50 Modèle 1924 gun French equivalent*20.3 cm SK C/34 Naval gun German equivalent*203 mm /53 Italian naval gun Italian equivalent*20 cm/50 3rd Year Type naval gun Japanese equivalent*BL 8 inch Mk VIII naval gun UK equivalent
References
Bibliography * * *** "Mystery in the Desert Is a Mystery No More".
External links