8-inch/55-caliber gun

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 45 lb of smokeless powder gave a 260 lb projectile a velocity of 2800 feet per second (853 m/s). Range was 18 miles 31860 yd 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 30050 yd 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

• 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
    • Northampton was sunk in November 1942
• 2 (c. 1930) heavy cruisers:
  • ,
    • Mk 9 (later Mk 14) guns in three 250-ton triple turrets
    • Indianapolis was sunk in July 1945
• 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
    • Astoria was sunk in August of 1942
  • 4 of 7: , , ,
    • Mk 12 guns in three 250-ton triple turrets
    • Quincy and Vincennes were sunk in August 1942
• • 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 installation

References

Bibliography

• "Mystery in the Desert Is a Mystery No More".

References

1. Campbell 1985 pp.127-131
2. [http://www.maritime.org/doc/ordnance/pg056.htm 8-inch shell info at San Francisco Maritime National Park website]
3. Fairfield 1921 p.156
4. DiGiulian, Tony. (27 April 2011). "United States of America 8"/55 (20.3 cm) Marks 9, 10, 11, 13 and 14". Navweaps.com.
5. DiGiulian, Tony. (7 February 2008). "United States of America 8"/55 (20.3 cm) Marks 12 and 15". Navweaps.com.
6. [https://books.google.com/books?id=ZiQDAAAAMBAJ&dq=popular+science+1949+%22earth+satellite+vehicle%22&pg=PA107 '' "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.
8. [http://www.fortwiki.com/Battery_Louis_R._Burgess FortWiki article on Battery Burgess]
9. [http://www.fortwiki.com/Battery_Lewis_S._Kirkpatrick FortWiki article on Battery Kirkpatrick]
10. [http://www.fortwiki.com/Battery_Carroll_G._Riggs ForWiki article on Battery Riggs]
11. [http://www.fortwiki.com/Battery_George_Ricker FortWiki article on Battery George Ricker]
12. [http://www.fortwiki.com/Category:Hawaii_Turret_Battery FortWiki article on Hawaii turret batteries]
13. (2004). "American Seacoast Defenses, A Reference Guide". CDSG Press.
14. [http://cdsg.org/fort-and-battery-list/ List of all US coastal forts and batteries] at the Coast Defense Study Group, Inc. website
15. (10 January 2024). "Mystery in the Desert Is a Mystery No More".