The collection includes monthly lists of deaths of seamen, 1916-1989 (RSS/A); apprentices' indentures in the form of samples for the years 1845 to 1848, 1850, 1851, 1853 and 1856 (RSS/AI); returns of births and deaths of crew, 1914-1964 (RSS/B); returns of births and deaths of passengers 1914-1941, (RSS/C); alphabetical indexes of deaths of merchant seamen by enemy action or natural causes during the Second World War, (RSS/D); masters' certificates of competency and service, 1845-1927 (RSS/MC); crew lists and official logs, 90% for voyages ending in the year '5' e.g. 1915 (RSS/CL); fishing skippers and second hands certificates of competency and service, 1884-1907 (RSS/SC) and engineers' certificates of competency and service, 1862-1921 (RSS/EC).

Administrative / biographical background
By the Merchant Shipping Act of 1835 a Registrar and Register office of Merchant Seamen was set up under the Admiralty, in the Custom House in London. The object was to record the service of all British seamen and provide a registration of seamen to create a means of manning the Navy in times of war. The Mercantile Marine Act of 1850 authorized the transfer of the Registrar of Seamen from the Admiralty to the Board of Trade, and the Registrar also maintained a copy of all Certificates of Competency issued to masters and mates. By the Merchant Shipping Act of 1854, the Registrar of Seamen became the Registrar General of Seamen. Under the Merchant Shipping Act of 1872 the registry of vessels, formerly undertaken by the Commissioner of Customs, was transferred to the Registrar General of Seamen, who now became the Registrar General of Shipping and Seamen. See H. Llewellyn Smith, The Boards of Trade (London, 1928); P.G. Parkhurst, Ships of Peace (published privately, 1962); J.C. Sainty, Officials of the Board of Trade.