Coastal artillery

Coastal artillery is the branch of the armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications.

From the Middle Ages until World War II, coastal artillery and naval artillery in the form of cannons were highly important to military affairs and generally represented the areas of highest technology and capital cost among materiel. The advent of 20th-century technologies, especially military aviation, naval aviation, jet aircraft, and guided missiles, reduced the primacy of cannons, battleships, and coastal artillery. In countries where coastal artillery has not been disbanded, these forces have acquired amphibious capabilities. In littoral warfare, mobile coastal artillery armed with surface-to-surface missiles can still be used to deny the use of sea lanes.

It was long held as a rule of thumb that one shore-based gun equaled three naval guns of the same caliber, due to the steadiness of the coastal gun which allowed for significantly higher accuracy than their sea-mounted counterparts.^{[citation needed]} Land-based guns also benefited in most cases from the additional protection of walls or earth mounds. The range of gunpowder-based coastal artillery also has a derivative role in international law and diplomacy, wherein a country's three-mile limit of "coastal waters" is recognized as under the nation or state's laws.

One of the first recorded uses of coastal artillery was in 1381—during the war between Ferdinand I of Portugal and Henry II of Castile—when the troops of the King of Portugal used cannons to defend Lisbon against an attack from the Castilian naval fleet.

The use of coastal artillery expanded during the Age of Discoveries, in the 16th century; when a colonial power took over an overseas territory, one of their first tasks was to build a coastal fortress, both to deter rival naval powers and to subjugate the natives. The Martello tower is an excellent example of a widely used coastal fort that mounted defensive artillery, in this case, muzzle-loading cannon. During the 19th century, the Chinese Qing Dynasty also built hundreds of coastal fortresses in an attempt to counter Western naval threats.

Coastal artillery fortifications generally followed the development of land fortifications; sometimes separate land defence forts were built to protect coastal forts. Through the middle 19th century, coastal forts could be bastion forts, star forts, polygonal forts, or sea forts, the first three types often with detached gun batteries called "water batteries". Coastal defence weapons throughout history were heavy naval guns or weapons based on them, often supplemented by lighter weapons. In the late 19th century separate batteries of coastal artillery replaced forts in some countries; in some areas, these became widely separated geographically through the mid-20th century as weapon ranges increased. The amount of landward defence provided began to vary by country from the late 19th century; by 1900 new US forts almost totally neglected these defences. Booms were also usually part of a protected harbor's defences. In the middle 19th century underwater minefields and later controlled mines were often used, or stored in peacetime to be available in wartime. With the rise of the submarine threat at the beginning of the 20th century, anti-submarine nets were used extensively, usually added to boom defences, with major warships often being equipped with them (to allow rapid deployment once the ship was anchored or moored) through early World War I. In World War I railway artillery emerged and soon became part of coastal artillery in some countries; with railway artillery in coast defence some type of revolving mount had to be provided to allow tracking of fast-moving targets.

Coastal artillery could be part of the Navy (as in Scandinavian countries, war-time Germany, and the Soviet Union), or part of the Army (as in the Anglosphere alignment for significant english-speaking countries). In English-speaking countries, certain coastal artillery positions were sometimes referred to as 'Land Batteries', distinguishing this form of artillery battery from for example floating batteries. In the United Kingdom, in the later 19th and earlier 20th Centuries, the land batteries of the coastal artillery were the responsibility of the Royal Garrison Artillery.

In the United States, coastal artillery was established in 1794 as a branch of the Army and a series of construction programs of coastal defenses began: the "First System" in 1794, the "Second System" in 1804, and the "Third System" or "Permanent System" in 1816. Masonry forts were determined to be obsolete following the American Civil War, and a postwar program of earthwork defenses was poorly funded. In 1885 the Endicott Board recommended an extensive program of new U.S. harbor defenses, featuring new rifled artillery and minefield defenses; most of the board's recommendations were implemented. Construction on these was initially slow, as new weapons and systems were developed from scratch, but was greatly hastened following the Spanish–American War of 1898. Shortly thereafter, in 1907, Congress split the field artillery and coast artillery into separate branches, creating a separate Coast Artillery Corps (CAC) The CAC was disbanded as a separate branch in 1950.