During the summer of 1918. when German submarines thrust into North American coastal waters, Sydney. Nova Scotia suddenly became a major naval base and Canada’s foremost convoy assembly harbour.1 Nearly a hundred of the Royal Canadian Navy’s coastal patrol vessels came to the Cape Breton port, with at least 1,500 crewmen and shore personnel,2 but this was not enough. Britain was unable to help. Therefore the United States Navy pitched in for what was the first instance of joint operations by the armed forces of the two North American nations. Some 350 American sailors came to establish base facilities and operate patrol vessels and aircraft assigned to Sydney. Thousands more passed through on ships assembling for convoy. Just as the naval authorities at Sydney had to cope with rapidly changing and increasing operational demands, so too the citizens had to deal with a veritable naval invasion of their town.