5-inch/51-caliber gun

Description

The different marks of the gun were Marks 7, 8, 9, 14, and 15. The built-up gun consisted of a tube, full-length jacket, and single hoop with side swing Welin breech block and Smith-Asbury mechanism for a total weight of about 5 metric tons. Some Marks included a tapered liner. A 24.5 lb charge of smokeless powder gave a 50 lb projectile a velocity of 3150 ft/s. Range was 15850 yd at the maximum elevation of 20 degrees.

US service

The 5-inch/51 caliber gun was designed to engage destroyers, torpedo boats, and other surface targets. The 5"/51 gun entered service in 1911 as secondary armament on the s, which mounted 16. The guns served well through World War I, but increased awareness of the need for anti-aircraft protection (especially following the attack on Pearl Harbor) encouraged mounting of dual-purpose 5"/38 caliber guns in later battleships, and some of the World War I-era battleships were rearmed with dual purpose guns as well. Surplus 5"/51 guns from scrapped or rearmed battleships were mounted in United States Coast Guard cutters, auxiliaries, small aircraft carriers, coast defense batteries, and Defensively Equipped Merchant Ships. A 1939 Table of Organization and Equipment shows Marine defense battalions were equipped with six of these guns each. 5-inch/51 shore batteries were used with great effectiveness by the 1st Marine Defense Battalion during the Battle of Wake Island in December 1941. These were replaced in the defense battalions by the 155 mm Long Tom gun by 1943. Six s were rearmed with "wet mount" 5-inch/51 guns during World War II, taken from Barracuda-class submarines or spares for that class.

The 5"/51 caliber gun was mounted on:

• • replacing 10 5"/40 and 4 8"/35 guns in 1917
• • replacing 2 5"/50 and 4 3"/50 guns in 1917
• • replacing 2 5"/50 and 4 3"/50 guns in 1917
• • replacing 2 5"/50 and 4 3"/50 guns in 1917
• (Gun nos. 489–509)
• (Gun nos. 468–488)

Five s:

Army coast defense use

5"/51 caliber ex-Navy guns were emplaced during World War II at several locations, some operated by the United States Army Coast Artillery Corps and some by Marine defense battalions. This list may not be exhaustive. They were grouped into two-gun batteries unless otherwise noted.

• Two guns near Cape Lookout, NC
• Three guns in Battery Gillespie, Point Loma, San Diego, CA
• Three guns in Battery Ahua, Fort Kamehameha, Oahu, HI
• Two guns in Battery Nanakuli, Oahu, HI
• Two guns in Battery Oneula (Ewa), Oahu, HI
• Two guns at Kahana Bay, North Shore, Oahu, HI

British service

In British service these guns were known as 5"/51 BL Mark VI and Mark VII. During World War I three of these guns formed part of the coastal defences of Scapa Flow. In World War II a small number of these guns entered British service on board ships transferred under the Lend-Lease arrangement. Some of these guns were then transferred to New Zealand (at least six, possibly more) and deployed ashore for coastal defence.

Surviving examples

Surviving 5"/51 caliber guns include:

• Eight guns on , preserved at the Independence Seaport Museum in Philadelphia, Pennsylvania (guns previously on )
• Six guns preserved on near Houston, Texas
• One Mark 8 gun (Four Lakes #1205) at Trumbo Point, Key West, Florida (part of Naval Air Station Key West)
• One gun (Unk. mfr. #1093L2) at the Ropkey Armor Museum, Crawfordsville, Indiana (previously on and allegedly on at some time)
• Two Mark 7 guns (Watervliet #774 and #Unk.) on Midway Island, Central Pacific Ocean
• One Mark 7 gun (Naval Gun Factory (NGF) #415L) at the NROTC facility, Tulane University, New Orleans, Louisiana
• One Mark 15 gun (NGF #736L) at the U.S. Navy Museum, Washington Navy Yard, Washington, DC (previously on )
• One 5"/51 caliber gun at Fort Schuyler, Bronx, New York (possibly at USMMA, Kings Point, New York)
• One 5"/51 caliber gun at Treasure Island, San Francisco, California (behind museum)
• One Mark 15 gun in Lewiston, Maine
• One Mark 15 gun (Bethlehem #Unk.) at the Brunswick Executive Airport, Brunswick, Maine (formerly NAS Brunswick)
• One 5"/51 caliber gun in Mitchell, Indiana
• One Mark 9 Mod 3 gun (NGF #938L), https://web.archive.org/web/20160623222312/http://www.tankland.com/visitorsinfo.html at The American Military Museum, South El Monte, California
• One 5"/51 caliber gun at the Veterans Memorial Museum, Chehalis, WA
• Two 5"/51 caliber guns at the Veterans Memorial in Haddon Heights, NJ

Notes

References

References

1. Fairfield 1921 p. 156
2. Useful life expectancy was 900 [[List of British ordnance terms#Effective Full Charge
3. Bogart, Charles H., "Fifth Marine Defense Battalion in Iceland", ''Coast Defense Journal'', Vol. 29, Issue 3, August 2015, Coast Defense Study Group, Inc.
4. Bauer and Roberts, p. 144
5. Preston 1980 p. 60
6. Breyer 1973 p. 201
7. Breyer 1973 p. 202
8. Breyer 1973 p. 205
9. Friedman 2011 p. 185
10. Breyer 1973 p. 210
11. Breyer 1973 p. 214
12. Breyer 1973 p. 219
13. Breyer 1973 p. 226
14. Breyer 1973 p. 230
15. Bauer and Roberts, pp. 178-179
16. Fahey 1939 p. 18
17. Bauer and Roberts, p. 265
18. Fahey 1939 p. 7
19. Friedman 1983 p. 162
20. Friedman 1983 p. 407
21. Friedman 1983 p. 164
22. Friedman 1983 p. 170
23. Fahey 1941 p. 42
24. DiGiulian, Tony, [http://www.navweaps.com/Weapons/WNUS_5-51_mk7.htm "United States of America 5"/51 (12.7 cm) Marks 7, 8, 9, 14 and 15. British 5"/51 (12.7 cm) BL Marks VI and VII]
25. Berhow, pp. 238-239