According to Montgomery, the involvement of a submarine is supported by numerous sightings of submarines or submarine-like objects in Australian waters, particularly a sighting off Townsville in late October of six "strange boats" that surfaced, sprouted wings, and flew off; he interpreted this as a floatplane-carrying Japanese submarine, which may have reached Carnarvon in time to attack "Sydney". The Cole report noted that false submarine sightings are a common wartime occurrence. In addition, the positions of all 46 active Japanese submarines at the time of the battle have been accounted for: 28 were in Japanese waters preparing for the attack on Pearl Harbor, seven were readying for operations in the South China Sea and Philippines, nine were heading for the South China Sea, and two had just departed for patrols in the Pacific.