7"/44 caliber gun
| 7"/44 caliber Mark 1 and 7"/45 caliber Mark 2 Naval Gun | |
|---|---|
|
USS Minnesota (BB-22), cropped photo showing close up of port side 7"/45 caliber guns. | |
| Type | |
| Place of origin |
 United States |
| Service history | |
| In service | 1906 |
| Used by |
 United States Navy |
| Wars | |
| Production history | |
| Designer | Bureau of Ordnance |
| Designed | 1900 |
| Manufacturer | Naval Gun Factory |
| Number built |
|
| Variants | Mark 1 and Mark 2 |
| Specifications | |
| Weight |
|
| Length |
|
| Barrel length |
|
|
| |
| Shell |
|
| Caliber | 7 in (178 mm) |
| Breech | Mark 1: Welin breech block |
| Recoil |
|
| Elevation | -7° to +15° |
| Traverse | −150° to +150° |
| Rate of fire | 4 rounds per minute |
| Muzzle velocity | 2,700 ft/s (820 m/s) |
| Effective firing range | 16,500 yd (15,100 m) at 15° elevation |
_cropped_port_side_view.jpg)
The 7"/44 caliber gun Mark 1 (spoken "seven-inch-forty-four--caliber") and 7"/45 caliber gun Mark 2 (spoken "seven-inch-forty-five--caliber") were used for the secondary batteries of the United States Navy's last generation of pre-dreadnought battleships, the Connecticut-class and Mississippi-class. The 7-inch (178 mm) caliber was considered, at the time, to be the largest caliber weapon sutiable as a rapid-fire secondary gun because its shells were the heaviest that one man could handle alone.[1][2]
Design
The 7-inch Mark 1 was built in a length of 44 calibers, had a nickel-steel liner, with a tube, jacket and three hoops with a locking ring, all made of gun steel, a screw box liner, and Welin breech block. The Mark 1 was hooped from the breech to 47.5 in (1,210 mm) from the muzzle. Only one Mark 1 was built, the prototype. The Mark 2 was the production version, it was of the same construction as the Mark 1 except that it was hooped all the way to the muzzle and had one caliber, or seven inches, added to its length. The Mark 2 Mod 1 was constructed with a conical nickel-steel liner. Two experimental Mark 2 guns, given serial numbers 2 and 3, were built with wider diameter breech ends, with gun No. 2 modified with a conical nickel-steel liner and modified breech, becoming Mark 2 Mod 2.[1][2]
Most of the 7-inch guns were removed before World War I and some were mounted on Mark V tractor mounts that had been designed by the Bureau of Ordnance (BuOrd) and built in Philadelphia by the Baldwin Locomotive Works. The mounts were not self-propelled; the tracked mounting was for cross-country mobility, and they would be towed by a Holt tractor or other vehicle.[3] The Marines ordered 20 of these guns, with the Army later ordering 36; before the Armistice was signed all 20 were delivered to the Marines, while 18 were completed postwar for the Army.[1][2][3]
The Army had requested these guns because of their lack of heavy artillery in France. The 20 guns for the Marines were to go to the new 10th Marine Artillery Regiment that was training at Quantico, Virginia in the fall of 1918. The Marines fired the first shot at Lower Station, Naval Support Facility Dahlgren today, 24,000 yd (22,000 m) down the Potomac River on 16 October 1918. In common with most US-produced heavy artillery in that war, none of the 7-inch guns were shipped to France or saw action.[3] In 1920 the BuOrd described the weapon as,
the heaviest and hardest hitting gun for which a mobile field mount of this kind had ever been requested by any nation or army.
The gun and towed tractor mount are an ancestor of the self-propelled artillery that has played a major role in most wars since.[4]
Also in World War I, twelve 7-inch guns were mounted as railway artillery for the Army.[5][6] None were shipped overseas in that war. These appear to have been dismounted and used as coast artillery after the war.[3] However, at least one was transferred to Brazil as a railway gun in 1941.
Due to the emergency situation at the beginning of World War II several of these guns were pressed into service as coastal defense batteries.[1]
Naval service
| Ship | Gun Installed | Gun Mount |
|---|---|---|
| USS Connecticut (BB-18) | Mark 2: 7"/45 caliber | Mark 1 and Mark 2: 12 × single pedestal for casemates |
| USS Louisiana (BB-19) | Mark 2: 7"/45 caliber | Mark 1 and Mark 2: 12 × single pedestal for casemates |
| USS Vermont (BB-20) | Mark 2: 7"/45 caliber | Mark 1 and Mark 2: 12 × single pedestal for casemates |
| USS Kansas (BB-21) | Mark 2: 7"/45 caliber | Mark 1 and Mark 2: 12 × single pedestal for casemates |
| USS Minnesota (BB-22) | Mark 2: 7"/45 caliber | Mark 1 and Mark 2: 12 × single pedestal for casemates |
| USS New Hampshire (BB-25) | Mark 2: 7"/45 caliber | Mark 1 and Mark 2: 12 × single pedestal for casemates |
| USS Mississippi (BB-23) | Mark 2: 7"/45 caliber | Mark 1 and Mark 2: 8 × single pedestal for casemates |
| USS Idaho (BB-24) | Mark 2: 7"/45 caliber | Mark 1 and Mark 2: 8 × single pedestal for casemates |
Coast defense locations
7-inch guns were emplaced during World War II at numerous locations, operated by the United States Army Coast Artillery Corps. This list is not exhaustive. They were grouped into two-gun batteries unless otherwise noted.[7]
- Two guns at Battery Zeilin, Fort Rosecrans, San Diego, CA
- Four guns in the Harbor Battery, Sand Island in Honolulu harbor, HI
- Two guns in the casemated "Hulu" battery, Pu'u O Hulu Military Reservation, Oahu, HI
- Three guns in the "Homestead" battery, Keaau Homesteads, Oahu, HI
- Four guns in two unnamed batteries on Kauai at Ahukini and Monument.
- At least eight guns in Batteries North, East, West, and South at Bora Bora, French Polynesia
- An unknown number of railway guns were transferred to Brazil in 1941; one is preserved there
Survivors
At least twelve guns are preserved, ten of them Mark 2 guns used for coast defense in World War II.
- Fort DeRussy, Honolulu, Hawaii
- Bora Bora, French Polynesia
- Seven guns, Naval Gun Factory Nos. 81, 82, 96, 97, Watervliet Nos. 57 and 60, Midvale No. 89. The two Watervliet guns were formerly on USS Louisiana, the Midvale gun was on USS New Hampshire.[8]
- Papeete, Tahiti, French Polynesia
- Naval Surface Warfare Center Dahlgren, Dahlgren, Virginia - only surviving tractor-mounted gun
- Museu Militar Conde de Linhares, Rio de Janeiro, Brazil - Only surviving 7-inch railway gun
Notes
- 1 2 3 Friedman 2011, pp. 179.
- 1 2 3 4 Williford 2016, pp. 100–101.
- ↑ Joyce 2009.
- ↑ Hartwell 2002.
- ↑ Miller 1924.
- ↑ Berhow 2015, pp. 216-226, 235.
- 1 2 3 Berhow 2015, p. 235.
References
- Books
- Friedman, Norman (2011). Naval Weapons of World War One. Seaforth Publishing. ISBN 978 1 84832 100 7.
- Williford, Glen (2016). American Breechloading Mobile Artillery, 1875-1953. Atglen, PA: Schiffer Publishing, Ltd. ISBN 978 0 7643 5049 8.
- Berhow, Mark A., Ed. (2015). American Seacoast Defenses, A Reference Guide, Third Edition. McLean, Virginia: CDSG Press. ISBN 978-0-9748167-3-9.
- Miller, H. W., LTC, USA (1921). A Report on the Characteristics, Scope of Utility, Etc. of Railway Artillery Vols. I and II. 1. Retrieved 4 November 2016.
- Online sources
- "United States of America 7"/44 (17.8 cm) Mark 1 7"/45 (17.8 cm) Mark 2". Navweaps. 30 July 2016. Retrieved 20 October 2016.
- Hartwell, Joe (21 September 2002). "US Army Railway Artillery Projects". Retrieved 4 November 2016.
- Joyce, John J. (23 July 2009). "First Gun Fired at Dahlgren in 1918 Returns Home". Dahlgren, Virginia. Retrieved 11 May 2016.
External links
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