monitor (ship)

monitor type of turreted warship (no longer used) carrying heavy guns, having little draft, and lying low in the water. Monitors were so called from the first of the class, the Monitor, built for the Union navy in the U.S. Civil War by John Ericsson . Launched in Jan., 1862, the Monitor was 179 ft (55 m) long, of 41.5-ft (13-m) beam, and weighed 1,200 tons. A revolving turret, protected by 8 in. (20.3 cm) of iron armor and containing two 11-in. (27.9-cm) smooth-bore guns, was its main feature. The sides were covered by iron plates from 3 to 5 in. (7.6-12.7 cm) thick, with about 27 in. (69 cm) of wood backing, and the deck, only 18 in. (46 cm) above water, was shielded with 1-in. (2.54-cm) armor. The ship was moved by steam power, with a screw propeller. (See Monitor and Merrimack for more information.) Monitors were used extensively in the Civil War, but the type had limitations—it was too heavy to navigate the oceans—and was eventually abandoned. However, they were used by the British navy in World War I.

monitor, a low-freeboard, shallow-draft ship mounting one or two large guns for coastal bombardment. The name comes from the original ship built for that purpose, an ironclad designed during the American Civil War (1861–5) for the US Navy by a Swedish engineer, John Ericsson (1803–89). Ericsson, who had already designed the first warship with a propeller, had the Monitor constructed to counter the Confederate States Navy ironclad CSS Virginia, the former USS Merrimac, as well as Confederate shore batteries. She was significant in the history of warships for being the first vessel to be built with an armoured revolving turret. On 9 March 1862, soon after her launch, she encountered the Virginia at Hampton Roads, but the battle proved inconclusive. By then she had already proved herself unseaworthy, and she foundered off Cape Hatteras on 31 December 1862. Her remains were found in 1973 by an American research ship and in 1975 became the USA's first marine sanctuary. They are protected by the National Oceanic and Atmospheric Administration (NOAA) which examined the hull but found it too fragile to be recoverable. However, the turret was salvaged in 2003 and is now on display at the Mariners' Museum, Newport News, Virginia.

The name monitor was chosen from a phrase in a letter from Ericsson to the secretary of the navy about the design: ‘The impregnable and aggressive character of the structure will admonish the leaders of the Southern Rebellion that the batteries on the banks of their rivers will no long present barriers to the entrance of the Union forces. The ironclad intruder will thus prove a severe monitor to those leaders … Downing Street [a reference to the British Prime Minister and his government], in fact, will hardly view with indifference this last Yankee notion, this monitor.’

Britain, in fact, viewed the Monitor with complete indifference, having two years earlier launched the Warrior, which could have blown 50 monitors out of the water. Nevertheless, Britain built monitors in large numbers during the First World War (1914–18) and also used them in the Second World War (1939–45).

monitor former term for a shallow-draught warship mounting one or two heavy guns for bombardment, named for a vessel developed by Swedish engineer John Ericsson for the Union forces. In a letter of 1862 he said that he proposed to name the new battery Monitor on the ground that ‘The iron-clad intruder will thus prove a severe monitor [that is, something providing guidance to moral conduct] to those leaders [of the Southern rebellion].’

This prototype vessel engaged the Confederate ironclad Virginia in Chesapeake Bay in a battle that drew worldwide attention; after this a number of similar warships were built by the Union. The original Monitor, however, went down off Cape Hatteras in 1862.