Five cable-laying ships have been named CS Monarch, or, after the nationalisation of British telegraph companies, HMTS Monarch:CS Monarch (1830), a paddle steamer built in 1830, used as a cable ship by Electric Telegraph Company from 1853 onwards. CS Monarch (1883), built in 1883 for the Post Office. Sunk 1915 off Folkestone in World War I. CS Monarch (1916), built in 1916 as a replacement for CS Alert but named Monarch after the 1915 sinking. Badly damaged by friendly fire from an American ship during the Normandy landings. Sunk by U-boat off Folkestone 16 April 1945 after repairing a cable to the Netherlands. CS Monarch (1945), launched in 1945 and completed in 1946 she was renamed CS Sentinel in 1970 and broken up in 1977. CS Monarch (1973), launched in 1973 and broken up in 2003.