Some older books on US sub operations credit the USS Nautillus for finishing off the Soryu at Midway. It is now knownn that her torpedo actually hit the Kaga, and that it was a dud (common for US torpedoes in the early years of the war). Maybe he made a mistake in his tally? Or maybe I am wrong, which is also quite possible.
I read Silent Victory about a year ago, but don't remember much about it now.