The 8-inch Navy gun Mk.VI M3A2 on railway mount M1A1 was a

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

improved replacement for the

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

-era 8-inch (203 mm) M1888 gun and was used by the US Army's

Coast Artillery Corps The U.S. Army Coast Artillery Corps (CAC) was an Corps#Administrative corps, administrative corps responsible for coastal defence and fortification, coastal, harbor, and anti-aircraft Seacoast defense in the United States, defense of the United S ...

in US harbor defenses. The guns were also mounted in fixed emplacements on the

barbette Barbettes are several types of gun emplacement in terrestrial fortifications or on naval ships. In recent naval usage, a barbette is a protective circular armour support for a heavy gun turret. This evolved from earlier forms of gun protection ...

carriage M1A1. These guns were US Navy surplus

8"/45 caliber gun The 8"/45 caliber Mark 6 gun (spoken "eight-inch-forty-five--caliber") were used for the secondary batteries of the United States Navy's last pre-dreadnought battleships and refitted in older armored cruisers main batteries. Design The /45 calibe ...

s from

battleship A battleship is a large armored warship with a main battery consisting of large caliber guns. It dominated naval warfare in the late 19th and early 20th centuries. The term ''battleship'' came into use in the late 1880s to describe a type of ...

s scrapped under the 1922

Washington Naval Treaty The Washington Naval Treaty, also known as the Five-Power Treaty, was a treaty signed during 1922 among the major Allies of World War I, which agreed to prevent an arms race by limiting naval construction. It was negotiated at the Washington Nav ...

. Mark VI (also Mark 6) was the Navy designation. The Army designation for this gun was "8-inch Navy gun Mk.VI M3A2".

History

The ex-Navy Mark VI

railway gun A railway gun, also called a railroad gun, is a large artillery piece, often surplus naval artillery, mounted on, transported by, and fired from a specially designed railroad car, railway wagon. Many countries have built railway guns, but the ...

was quickly put together at the start of World War II, to supplement the older World War I

8-inch M1888 The 8-inch gun M1888 (203 mm) was a U.S. Army Coast Artillery Corps gun, initially deployed 1898–1908 in about 75 fixed emplacements, usually on a disappearing carriage. During World War I, 37 or 47 of these weapons (references vary) w ...

railway gun. It was developed from an experimental 12-inch (305 mm) railway

howitzer A howitzer () is a long- ranged weapon, falling between a cannon (also known as an artillery gun in the United States), which fires shells at flat trajectories, and a mortar, which fires at high angles of ascent and descent. Howitzers, like ot ...

carriage of World War I. The all-around rotating mount and outriggers were designed to allow the gun to track a moving target for coast defense. These guns had a very short life in Army use, entering service in February 1941 and being cut up for scrap immediately after the war. The guns were the Navy's 8-inch (203 mm)/45 caliber Mark VI, and were originally secondary armament on ''Virginia''- and ''Connecticut''-class battleships launched 1904-06 and scrapped in the 1920s. They were mounted in both fixed emplacements and on the M1A1 railway carriage.

Deployment

* Fixed two-gun batteries at Fort Church (

Narragansett Bay Narragansett Bay is a bay and estuary on the north side of Rhode Island Sound covering , of which is in Rhode Island. The bay forms New England's largest estuary, which functions as an expansive natural harbor and includes a small archipelago. Sma ...

Rhode Island Rhode Island (, like ''road'') is a U.S. state, state in the New England region of the Northeastern United States. It is the List of U.S. states by area, smallest U.S. state by area and the List of states and territories of the United States ...

Fort Rosecrans Naval Base Point Loma (NBPL) is located in Point Loma, a neighborhood of San Diego, California. It was established on 1 October 1998 when Navy facilities in the Point Loma area of San Diego were consolidated under Commander, Navy Region Southwest ...

(

San Diego San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the List of United States cities by population, eigh ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

Fort Ruger Fort Ruger is a fort on the island of Oahu that served as the first military reservation in the Territory of Hawaii. Named after Civil War General Thomas H. Ruger and built in and around Diamond Head Crater, the fort was established by the Unite ...

and two other locations (

Oahu Oahu () (Hawaiian language, Hawaiian: ''Oʻahu'' ()), also known as "The Gathering place#Island of Oʻahu as The Gathering Place, Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over t ...

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

) (two not completed),

Fort Schwatka The Aleutian World War II National Historic Area is a U.S. National Historic Site on Amaknak Island in the Aleutian Islands, Aleutian Island Chain of Alaska. It offers visitors a glimpse of both natural and cultural history, and traces the histori ...

(

Dutch Harbor, Alaska Dutch Harbor is a harbor on Amaknak Island in Unalaska, Alaska. It was the location of the Battle of Dutch Harbor in June 1942, and was one of the few sites in the United States to be subjected to aerial bombardment by a foreign power during Worl ...

Fort J. H. Smith A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from Latin ''fortis'' ("strong") and ''facere'' ...

and

Fort Abercrombie Fort Abercrombie, in North Dakota, was an American fort established by authority of an act of Congress, March 3, 1857. The act allocated twenty-five square miles of land on the Red River of the North in Dakota Territory to be used for a military ...

(

Kodiak, Alaska Kodiak (Alutiiq: , russian: Кадьяк), formerly Paul's Harbor, is the main city and one of seven communities on Kodiak Island in Kodiak Island Borough, Alaska. All commercial transportation between the island's communities and the outside wo ...

Fort Segarra Water Island ( da, Vand ø) is an island territory currently belonging to the United States Virgin Islands, an American territory located in the Caribbean Sea. The rest of the U.S. Virgin Islands were acquired by the Americans in 1917 from Denma ...

near St. Thomas in the

United States Virgin Islands The United States Virgin Islands,. Also called the ''American Virgin Islands'' and the ''U.S. Virgin Islands''. officially the Virgin Islands of the United States, are a group of Caribbean islands and an unincorporated and organized territory ...

, and

Roosevelt Roads Roosevelt Roads Naval Station is a former United States Navy base in the town of Ceiba, Puerto Rico. The site operates today as José Aponte de la Torre Airport, a public use airport. History In 1919, future US President Franklin D. Rooseve ...

Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...

(not armed). * Railway guns: 8 at

Fort Miles Fort Miles was a United States Army World War II installation located on Cape Henlopen near Lewes, Delaware. Although funds to build the fort were approved in 1934, it was 1938 before construction began on the fort. On 3 June 1941 it was name ...

Delaware Delaware ( ) is a state in the Mid-Atlantic region of the United States, bordering Maryland to its south and west; Pennsylvania to its north; and New Jersey and the Atlantic Ocean to its east. The state takes its name from the adjacent Del ...

, two 4-gun batteries each in the

Los Angeles Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...

and

Puget Sound Puget Sound ( ) is a sound of the Pacific Northwest, an inlet of the Pacific Ocean, and part of the Salish Sea. It is located along the northwestern coast of the U.S. state of Washington. It is a complex estuarine system of interconnected ma ...

harbor defenses and

Fort John Custis Colonel John Custis IV (August 1678 – November 22, 1749) was an American planter, politician, government official and military officer who sat in the House of Burgesses from 1705 to 1706 and 1718 to 1719, representing the electoral constitue ...

near Cape Charles,

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

, others at

Fort Hancock, New Jersey Fort Hancock is a former United States Army fort at Sandy Hook in Middletown Township New Jersey. The coastal artillery base defended the Atlantic coast and the entrance to New York Harbor, with its first gun batteries operational in 1896. The ...

(near

New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

).Gaines, William C., Coast Artillery Organizational History, 1917-1950, ''Coast Defense Journal'', vol. 23, issue 2, pp. 6-8, 25-27
/ref>

Sighting and fire control equipment

The following sighting equipment was used with the gun. * M1 Deflection board * M1 fire adjustment board * M1A1 Range correction board * M3 Spotting board * M1912 Clinometer * M1 Percentage corrector * M1A1 Height finder, or M2A1 * M6 Azmuth indicator * M5 Elevation indicator * M1910A1 Azmuth instrument * M8 Helium filling kit * M1 Gunners quadrant * Type B, set forward rule * M1 prediction scale * bore site * firing table, 8-I-1. * M7 stereoscopic trainer * M1 generating unit

Support cars

* M2 fire control car * M1 machine shop car * modified box car for ammunition

Surviving Examples

Four weapons of this type survive: * One gun at

, Delaware, on M1 railway proof mount (experimentally bored out to ) (was previously at

Naval Surface Warfare Center * A Naval Surface Warfare Center (NSWC) is part of the Naval Sea Systems Command (NAVSEA) operated by the United States Navy. NAVSEA Warfare Centers supply the technical operations, people, technology, engineering services and products needed t ...

Dahlgren Division, Dahlgren, VA * Two 8-inch Guns Mk VI M3A2 (#160L2 & #154L2), Battery 404,

, Kodiak, AK * One 8-inch Gun Mk VI M3A2 (#134L2),

Kodiak Airport Kodiak Benny Benson State Airport is a public and military use airport located four nautical miles (5 mi, 7 km) southwest of the central business district of Kodiak, a city on Kodiak Island in the U.S. state of Alaska. The airp ...

, Kodiak, AK (gun formerly at Battery 403, Fort J.H. Smith, Kodiak, AK)

References

* * * SNL E-34 * * *

External links

Navweaps.com 8-inch Mark VI gun photo page

Breech operation on preserved gun at Fort Miles

Coast Artillery Journal, Nov-Dec 1942, with article on 8" Mk VI M3A2 guns
{{WWIIUSGuns World War II artillery of the United States Coastal artillery Railway guns 203 mm artillery Weapons and ammunition introduced in 1941