8"/55 caliber gun

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8"/55 caliber naval gun
Damages New Orleans Tassafaronga.jpg
No. 2 turret of USS New Orleans (CA-32) following a Japanese torpedo-initiated explosion of the forward magazine during the Battle of Tassafaronga on 30 November 1942.
Type Naval gun
Coastal defence
Service history
In service 1925–1975
Used by  United States
Wars World War II
Korean War
Vietnam War
Production history
Variants Mk 9, Mk 12, Mk 14, Mk 15, Mk 16
Specifications
Barrel length 440 inches (11 m) bore (55 caliber)

Shell

335 pounds (152 kg)[1]A.P.

260 pounds (118 kg)[2] H.E.
Caliber 8 inches (20 cm)
Muzzle velocity 2,500 feet per second (760 m/s)[1]
Maximum firing range 30,050 yards (27,480 m)[1]

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 11 meters).[3]

Compare the rounded roofs of early Mark 9 twin and triple turrets of USS Salt Lake City (CA-25) and USS Pensacola (CA-24) with the later turrets of USS New Orleans (CA-32) on the right.

Mark 9[edit]

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 45-pounds (20 kg) of smokeless powder gave a 260-pound (120 kg) projectile a velocity of 2800 feet per second (850 m/s).[1] Range was 31,860 yd (29,130 m) at the maximum elevation of 41 degrees.[1][4]

Mark 12[edit]

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).[1] Each gun could fire about four rounds per minute. Maximum range was 30,050 yd (27,480 m) at the maximum elevation of 41 degrees.[5]

Mark 14[edit]

These guns were similar to Mark 9, with the same shell weight and maximum range,[4] with a smaller chamber and rifling twist increased from 1 in 35 to 1 in 25 in a chromium-plated bore.

Mark 15[edit]

These guns were similar to Mark 12, with the same shell weight and maximum range, with the smaller chamber of the Mark 14 gun.[5] Useful life expectancy was 715 effective full charges (EFC) per liner.

Mark 16[edit]

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).[1] Each gun could fire about ten rounds per minute. Useful life expectancy was 780 EFC per liner. Range was 17 miles (27 kilometers) at the maximum elevation of 41 degrees.[1][6][7] This gun was modified for the experimental Major Caliber Lightweight Gun.

Coast defense use[edit]

The eight twin turrets of Lexington and Saratoga 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),[8] Wiliwilinui Ridge Military Reservation (Battery Wilridge, later Battery Kirkpatrick),[9] Opaeula Military Reservation (Battery Opaeula, later Battery Riggs),[10] and Brodie Camp Military Reservation (Battery Brodie, later Battery George Ricker).[11][12][13][14] After the war, all of the guns and turrets were scrapped in 1948, along with almost all other US coast artillery. One of USS Louisville CA 28 main gun turrets was removed and taken to the Nevada Test Site and converted into a rotating radiation detector, to collect data on nuclear tests: "Mystery in the Desert Is a Mystery No More".

Ships mounting 8"/55 caliber guns[edit]

The heavy cruiser USS Helena (CA-75) fires her 8"/55 caliber Mark 15 guns at enemy forces ashore on the Korean Peninsula in August 1950 during the Korean War.
The after turret of the heavy cruiser USS Toledo (CA-133) fires its 8"/55 caliber Mark 15 guns at enemy targets ashore around Incheon, South Korea, on 13 or 14 September 1950 during the bombardment preceding the invasion of Incheon during the Korean War.
The heavy cruiser USS Saint Paul (CA-73) 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 USS Saint Paul (CA-73)'s forward 8"/55-caliber guns fire at enemy targets ashore in North Vietnam in October 1966 during the Vietnam War.
Ship Gun Installation[1]
USS Lexington (CV-2) Mk 9 guns in four 190-ton twin turrets
USS Saratoga (CV-3) Mk 9 guns in four 190-ton twin turrets
USS Pensacola (CA-24) Mk 9 (later Mk 14) guns in two 190-ton twin turrets
and two 250-ton triple turrets
USS Salt Lake City (CA-25) Mk 9 (later Mk 14) guns in two 190-ton twin turrets
and two 250-ton triple turrets
USS Northampton (CA-26) Mk 9 (later Mk 14) guns in three 250-ton triple turrets
USS Chester (CA-27) Mk 9 (later Mk 14) guns in three 250-ton triple turrets
USS Louisville (CA-28) Mk 9 (later Mk 14) guns in three 250-ton triple turrets
USS Chicago (CA-29) Mk 9 guns in three 250-ton triple turrets
USS Houston (CA-30) Mk 9 guns in three 250-ton triple turrets
USS Augusta (CA-31) Mk 9 (later Mk 14) guns in three 250-ton triple turrets
USS New Orleans (CA-32) Mk 9 (later Mk 14) guns in three 294-ton triple turrets
USS Portland (CA-33) Mk 9 (later Mk 14) guns in three 250-ton triple turrets
USS Astoria (CA-34) Mk 9 guns in three 294-ton triple turrets
USS Indianapolis (CA-35) Mk 9 (later Mk 14) guns in three 250-ton triple turrets
USS Minneapolis (CA-36) Mk 9 (later Mk 15) guns in three 294-ton triple turrets
USS Tuscaloosa (CA-37) Mk 12 guns in three 250-ton triple turrets
USS San Francisco (CA-38) Mk 12 guns in three 250-ton triple turrets
USS Quincy (CA-39) Mk 12 guns in three 250-ton triple turrets
USS Vincennes (CA-44) Mk 12 guns in three 250-ton triple turrets
USS Wichita (CA-45) Mk 12 guns in three 314-ton triple turrets
USS Baltimore (CA-68) Mk 12 guns in three 300-ton triple turrets
USS Boston (CA-69) Mk 15 guns in three 300-ton triple turrets
USS Canberra (CA-70) Mk 15 guns in three 300-ton triple turrets
USS Quincy (CA-71) Mk 15 guns in three 300-ton triple turrets
USS Pittsburgh (CA-72) Mk 15 guns in three 300-ton triple turrets
USS Saint Paul (CA-73) Mk 15 guns in three 300-ton triple turrets
USS Columbus (CA-74) Mk 15 guns in three 300-ton triple turrets
USS Helena (CA-75) Mk 15 guns in three 300-ton triple turrets
USS Oregon City (CA-122) Mk 15 guns in three 300-ton triple turrets
USS Albany (CA-123) Mk 15 guns in three 300-ton triple turrets
USS Rochester (CA-124) Mk 15 guns in three 300-ton triple turrets
USS Bremerton (CA-130) Mk 15 guns in three 300-ton triple turrets
USS Fall River (CA-131) Mk 15 guns in three 300-ton triple turrets
USS Macon (CA-132) Mk 15 guns in three 300-ton triple turrets
USS Toledo (CA-133) Mk 15 guns in three 300-ton triple turrets
USS Des Moines (CA-134) Mk 16 guns in three 450-ton triple turrets
USS Los Angeles (CA-135) Mk 15 guns in three 300-ton triple turrets
USS Chicago (CA-136) Mk 15 guns in three 300-ton triple turrets
USS Salem (CA-139) Mk 16 guns in three 450-ton triple turrets
USS Newport News (CA-148) Mk 16 guns in three 450-ton triple turrets
USS Hull (DD-945) Mk 16 gun in one 86-ton single automatic mount
(8"/55 caliber Mark 71 gun installation)

NOTE to the above table: Turret Structures with two guns which elevated together as an assembly were known as "Twin Turrets." Structures with three guns which elevated together were "Triple Turrets," etc. Turrets where the guns elevated independently of one another were distinguished by different nomenclature. A turret which contained two guns that elevated independently is properly termed a "Two Gun Turret" not a "Twin Turret" and one with three guns a "Three Gun Turret," not a "Triple Turret," etc. All Heavy Cruiser 8"/55cal. gun turrets beginning with the San Francisco Class and there after (Baltimore; Oregon City; and, Des Moines Classes) were "Three Gun Turrets." The same is true of turrets on Light Cruisers and Battleships.[citation needed]

See also[edit]

Weapons of comparable role, performance and era[edit]

References[edit]

  1. ^ a b c d e f g h i Campbell 1985 pp.127-131
  2. ^ 8-inch shell info at San Francisco Maritime National Park website
  3. ^ Fairfield 1921 p.156
  4. ^ a b DiGiulian, Tony (27 April 2011). "United States of America 8"/55 (20.3 cm) Marks 9, 10, 11, 13 and 14". Navweaps.com. Archived from the original on 30 June 2011. Retrieved 2011-07-21. 
  5. ^ a b DiGiulian, Tony (7 February 2008). "United States of America 8"/55 (20.3 cm) Marks 12 and 15". Navweaps.com. Archived from the original on 30 June 2011. Retrieved 2011-07-21. 
  6. ^ "New Cruiser Packs 8 inch Automatics" , May 1949, Popular Science detailed illustrations of Mark 16
  7. ^ DiGiulian, Tony (27 January 2011). "United States of America 8"/55RF (20.3 cm) Mark 16". Navweaps.com. Retrieved 2016-04-10. 
  8. ^ FortWiki article on Battery Burgess
  9. ^ FortWiki article on Battery Kirkpatrick
  10. ^ ForWiki article on Battery Riggs
  11. ^ FortWiki article on Battery George Ricker
  12. ^ FortWiki article on Hawaii turret batteries
  13. ^ Berhow, Mark A., Ed. (2004). American Seacoast Defenses, A Reference Guide, Second Edition. CDSG Press. pp. 118–119, 217–219. ISBN 0-9748167-0-1. 
  14. ^ List of all US coastal forts and batteries at the Coast Defense Study Group, Inc. website