DRY DOCKS

DRY DOCKS. Employed by the Greeks and Romans for construction and repair of war galleys, dry docks have constituted the foundations of naval architecture. Like the great dock house at Delos, which accommodated vessels up to twenty-eight feet wide, dry docks were typically, until the late Renaissance, erected on an inclined plane to facilitate launchings. Although such ship houses survived into nineteenth-century America, they were superseded in sixteenth-century Europe by open masonry basins erected below water level by means of cofferdams and fitted with watertight gates whose closure, upon entrance of a vessel, permitted the dock to be pumped dry. Henry VII ordered the construction of England's first dry dock—a wood and stone construction enclosed by walls of wood, stone, and earth—at Portsmouth in 1496. Under Henry VIII, dockyards at Woolwich and Deptford inaugurated major warship construction, spurring the building of dry docks elsewhere in Europe and opening three centuries of naval rivalry with Spain, the Netherlands, and France.

Construction features of those European establishments were embodied in the first federal dry dock erected in the United States, a 253-foot graving dock completed at Boston in 1833. Equipped with both copper-sheathed turning gates and a caisson (floating gate), this early work had substantial pump wells, pumping machines, discharge culverts, capstans, and the customary stock of keel blocking. The New York Navy Yard's 307-foot dock, opened in 1851, boasted the world's first all-metal cofferdam, with a sixty-eight-foot entrance and a maximum depth of twenty-six feet, completely adequate for the repair, construction, or routine bottom cleaning of the largest warships.

After floating dry docks were introduced in European and North American shipyards, the U.S. Navy decided to construct such "balance" docks at Portsmouth, New Hampshire (1800) and Pensacola, Florida, and to fabricate a floating sectional dry dock at Mare Island (1853). The advent of steel construction and the rapid increase in warship dimensions necessitated larger all-masonry docks and placed a severe strain on existing facilities. Following the Spanish-American War, 740-foot graving docks were constructed at Portsmouth, Boston, Philadelphia, and Mare Island. Increasing overseas responsibilities subsequently persuaded the navy to establish dry docks at Puget Sound and Pearl Harbor. During World War I, 1,000-foot dry docks equipped with massive traveling cranes and typically committed to Dreadnought construction were built at Norfolk, Philadelphia, and San Francisco.

On the eve of World War II, naval graving docks with reinforced concrete walls more than twenty feet thick were under construction at Norfolk and Philadelphia, designed to accommodate warships 1,100 feet long and 150 feet wide. The rapid strategic movement contemplated for American naval forces in the Pacific dictated that the floating dry dock join the U.S. Fleet's mobile service force. From 1942 to 1945, twenty-seven 457-foot landing ship docks (LSDs) were launched, many joining the Pacific fleet as combined dry docks and landing craft carriers. Capable of steaming into landing areas with their well decks filled with combat-loaded landing craft mechanized (LCMs), these amphibious mother ships discharged their craft through stern gates for direct beachhead assault.

BIBLIOGRAPHY

Mazurkiewicz, B. K. Design and Construction of Dry Docks. Rock-port, Mass.: Trans Tech, 1980.

Du-Plat-Taylor, Francis M. G. The Design, Construction and Maintenance of Docks, Wharves and Piers. London: Benn, 1928; 1934; London: Eyre and Spottiswoode, 1949.

Stuart, Charles B. The Naval Dry Docks of the United States. New York: Norton, 1852; New York: Van Nostrand; London: Trubner, 1870.

Philip K.Lundeberg/a. r.

See alsoColonial Ships ; Shipbuilding ; World War I, Navy in ; World War II, Navy in .