In The Search for the Japanese Fleet, I argue that Nautilus attacked the aircraft carrier Kaga, not Sōryū as Captain Brockman thought, owing to outdated recognition guides. The information in his possession showed Kaga in its pre-war configuration, with a three-quarter length flight deck and uncovered bow. Otherwise, the two ships resembled one another, and both had a unique starboard-side island superstructure. (Kaga was significantly heavier, 39,000 tons vs. 16,000 tons, as it was built on an armored battlecruiser hull, but that did not affect its appearance through the periscope.) Wreckage from a vessel identified as Kaga was found in 1999 at the position of the Nautilus attack. Yet Captain Brockman and his crew recovered a life ring from Sōryū! How can this be?
Nautilus made her attack at around 1400 local time and evaded depth-charging destroyers by heading south. Nautilus first surfaced that evening at 1941. By that time she was twenty miles south of the attack location, but much closer southwest of the location of the dive bomber attacks that mortally wounded both ships (as well as Akagi) that morning at 1020. With winds and currents pushing floating debris to the west, it is likely that Nautilus fell among flotsam from the morning attacks on all three ships rather than from the particular ship they attacked at 1400.
Regardless of which ship Nautilus attacked, the old boat and her gallant crew were key members of the team of aviators and sailors that caused the destruction of the carriers of Kidō Butai that June day in 1942 and turned the tide of the war in the Pacific.