The RCN expanded greatly during the Second World War. From its modest beginnings of six ocean-going ships and 3,500 officers and men (both regular and reserve) at the outbreak of the war, it grew into a large and capable fighting force. This was important as the navy was immediately called on to help. In fact, the navy was the main thrust of Canada’s war effort in the first two years of the conflict as German U-boats again made cutting off Allied shipping a top priority and the Allied navies had to find a way to protect the merchant vessels crossing the Atlantic Ocean so supplies could reach Europe.

This “Battle of the Atlantic” was the longest and one of the most important campaigns of the Second World War — lasting from the first day of the war in 1939 until the last day of the war in Europe in 1945. Canada played a major role with the RCN assuming responsibility for escorting convoys in the northwest Atlantic — the only major theatre of the war to be commanded by Canadians. This battle also saw the Germans bring the war to our own shores. U-boats even penetrated deep into the Gulf of St. Lawrence and the St. Lawrence River.