Accurate Lengths Of IJN ships ?

[Rockin Robbins]

And of course keep in mind that US records of Japanese ships were notoriously defective, both because of bad guesses and Japanese secrecy. More than half the targets shot at during the war, according to JANAC, were misidentified. Those which were properly identified often had grave errors in the recognition manual.

The American method of shooting torpedoes with stadimeter and position keeper was fatally flawed because stadimeters were difficult to begin with and our information on actual target measurements was incomplete and innacurate.

That, plus the American tendency to shoot from too far away, is why American shooting, torpedoes per hit and torpedoes per ton sank, were so much worse than the Germans. German shooting techniques did not demand target identification.