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 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