The Japanese efforts to secure New Guinea included a prolonged submarine offensive against the Allied lines of communication between the United States and Australia and Australia and New Guinea. These were not the first Axis naval attacks on Australia; during 1940 and 1941, five German surface raiders operated in Australian waters at various times. The German attacks were not successful in disrupting Australian merchant shipping, though "Sydney" was sunk with the loss her entire crew of 645 men in November 1941, in a battle with the German auxiliary cruiser "Kormoran", off the coast of Western Australia.