At the outbreak of war in August 1914, only three obsolete ships and two recently-acquired submarines protected Canada's west coast. Canadians feared that German cruisers might attack merchant ships or bombard cities and towns. After these attacks failed to materialize, many vessels and personnel were transferred to the Atlantic to deal with the growing German submarine threat.
At the start of the First World War, HMCS Rainbow was Canada's first line of naval defence on the west coast.
Rainbow steamed out of Esquimalt harbour on 3 August 1914, a day before Canada went to war. Heading south, its mission was to help protect the British sloops HMS Algerine and HMS Shearwater, which had been operating off the Mexican coast, against modern German cruisers known or suspected to be in the area. Obsolete, under-equipped, and with only half its crew, Rainbow would have stood little chance had it encountered any of these German ships.
George Metcalf Archival Collection