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.
Naval warfare of World War I included those at Heligoland Bight (two of them), Dogger Bank, and Jutland. Though British tactical success remains a subject of historical debate, Britain accomplished its strategic objective of maintaining the blockade and keeping the main body of the High Seas Fleet in port for the vast majority of the war. The High Seas Fleet remained a threat as a fleet in being that forced Britain to retain a majority of its capital ships in the North Sea. The set-piece battles and maneuvering have drawn historians' attention; however, it was the naval blockade of food and raw material imports into Germany