さて、どこに装甲貫通に関して、確定した見解が書いてあるんでしょうね

http://www.researcheratlarge.com/Ships/BB39/1944-10-31AnalysisOfLoss.html
http://www.researcheratlarge.com/Ships/BB39/1947-11-21MagazineExplosion.html

15. The evidence is not clear as to whether the bomb penetrated the third deck or a fire started by the bomb detonation passed through an open hatch in the third deck into the magazines.
Reference (a) stated that most of the armored hatches on the third deck were probably open at the time.
Reference (c) indicated that fragments from 4 of 5 bombs of which definite evidence was found of having hit ARIZONA penetrated the third deck.
The fifth bomb hit the faceplate of turret IV which may account for its detonation above the second deck.