British submarine flotilla in the Baltic A British submarine flotilla operated in the Baltic Sea for three years during the First World War . The squadron of nine submarines was attached to the Russian Baltic Fleet . The main task of the flotilla was to prevent the import of iron ore from Sweden to Imperial Germany . The success of the flotilla also forced the German Navy in the Baltic to keep to their bases and denied the German High Seas Fleet a training ground . The flotilla was based in Reval ( Tallinn ) , and for most of its career commanded by Captain Francis Cromie . The flotilla originally consisted of six E - class and five C - class submarines . The smaller C - class submarines reached the Baltic Sea through canals in Russia ; the long - range E - class submarines managed to enter the German backwaters by passing undetected through the narrow and shallow Danish Straits . Two of the subs were lost to stranding and one went missing , now presumed sunk by a mine . In 1918 , the German occupation of Tallinn and the Brest - Litovsk peace treaty forced the flotilla to move to Helsinki , under the protection of the Finnish Socialist Workers ' Republic . The German intervention in the Finnish Civil War and the landing of the 10 , 000 - strong German Baltic Sea Division in Hanko forced the crew to scuttle the eight remaining submarines and the three support ships , " Cicero " , " Emilie " and " Obsidian " , outside Helsinki harbour . A similar fate awaited the flotilla ' s Russian counterpart . The Ice Cruise of the Baltic Fleet had left four Russian " Holland type " submarines without support in Hanko . The arrival of German troops under Rüdiger von der Goltz on 3 April , forced the Russians to hastily scuttle the submarines — including and — in Hanko harbour . Submarines . E class . The E - class submarines entered the Baltic Sea through the Danish Straits through waters only 10 meters ( 35 ft ) deep . On 19 August 1915 , was stranded in The Sound near Saltholm . In a breach of Danish neutrality , she was destroyed by German torpedo boat " G132 " , with a loss of 15 of her crew . The other subs managed to enter the Baltic without being intercepted by the Germans . and made the passage to Reval safely in September 1915 . The last four E - class submarines — , , and — were scuttled outside Helsinki , south of the Harmaja Light , in 1918 to prevent capture by German troops who had landed nearby . C class . Four C - class submarines were sent there in September 1915 by a tortuous route — towed around the North Cape to Archangelsk and taken by barge to Krondstadt via the White Sea Canal . , , and reached Saint Petersburg on the Gulf of Finland in September 1916 , but due to difficulties with the batteries became fully operational only in the 1917 sealing season . Three of these boats — , , and — were also scuttled outside Helsinki in 1918 . Aftermath . The crews of the scuttled submarines were evacuated by Soviet ships to Petrograd and by rail to Murmansk , to join with the Allied intervention forces in North Russia , only weeks before hostilities cut railway lines to Murmansk . Among the officers were future Admirals and commanders of the British Submarine Service , Sir Noel Laurence and Sir Max Horton and Vice Admiral Leslie Ashmore . Admiral Aksel Berg also served as Liaison Officer from the Imperial Russian Navy , before going on to become the Deputy Minister of Defence for the Soviet Union ( 1953 – 57 ) . In 1935 , the Anglo - German Naval Agreement ( AGNA ) concluded between Britain and Germany , allowed Germany to increase the size of its navy to one - third the size of the Royal Navy , which would have had the effect of allowing the Kriegsmarine to dominate the Baltic . Finns raised some parts of the scuttled British submarines before the World War II but did not consider any of the submarines to be worth repairing . It is believed that the remains were raised in 1953 by the German company Beckedorf Gebryder and used as scrap metal . Wreck of " Cicero " is believed to have been located in 1995 .