Isle of Man Steam Packet Company England, Wales, Scotland and Ireland. Ports served included Liverpool, Silloth, Whitehaven, Holyhead, Ardrossan, Blackpool, Belfast and Dublin. Vessels and crews of the company were actively involved in both the First and Second World Wars. One vessel, , was attached to the British Grand Fleet and led the German High Seas Fleet into Scapa Flow in the Orkney Islands at the end of the First World War. Another vessel, "Viking", was converted to become a seaplane carrier, serving as . During the First World War, eleven out of a total fleet of fifteen Steam Packet ships were requisitioned by the Admiralty.
Atlantic U-boat campaign of World War I The other was the Battle of Ambos Nogales that was allegedly led by two German spies. On 20 October 1918 Germany suspends submarine warfare, and on 11 November 1918, World War I ended. The last task of the U-Boat Arm was in helping to quell the Wilhelmshaven mutiny, which had broken out when the High Seas Fleet was ordered to sea for a final, doomed sortie. After the Armistice, the remaining U-boats joined the High Seas Fleet in surrender, and were interned at Harwich. Of the 12.5 million tons of Allied shipping destroyed in World War I, over 8 million