prison ship , often more precisely described as a prison hulk , is a current or former seagoing vessel that has been modified to become a place of substantive detention for convicts , prisoners of war or civilian internees . While many nations have deployed prison ships over time , the practice was most widespread in seventeenth and eighteenth century Britain , as the government sought to address the issues of overcrowded civilian jails on land and an influx of enemy detainees from the War of Jenkins ' Ear , the Seven Years ' War and the French Revolutionary and Napoleonic Wars . The vessels were a common form of internment in Britain and elsewhere in the 18th and 19th centuries . Charles F. Campbell writes that around 40 ships of the Royal Navy were converted for use as prison hulks . Other hulks included , which became a prison ship at Woolwich in February 1840 . One was established at Gibraltar , others at Bermuda ( the '' Dromedary '' ) , at Antigua , off Brooklyn in Wallabout Bay , and at Sheerness . Other hulks were anchored off Woolwich , Portsmouth , Chatham , Deptford , and Plymouth-Dock/Devonport . HMS '' Agenta '' , originally a cargo ship with no portholes , was acquired and pressed into service in Belfast Lough Northern Ireland to enforce the Civil Authorities ( Special Powers ) Act ( Northern Ireland ) 1922 during the period around the Irish Catholics ' Bloody Sunday ( 1920 ) . Private companies owned and operated some of the British hulks holding prisoners bound for penal transportation to Australia and America
Bloody Sunday ( 1920 )
Bloody Sunday (1920)
Prison ship