My father (age, 78) has asked me to do some research for him.
A friend of his believes that all the battleships on battleship row on December the 7th 1941 had all their bottom void tanks open for a BuShip InSurv (Inspection & Survey) inspection. I think I have recalled that it was true but he wants documentation.
I suspect somewhere the US Navy has a record of ordering an Inspection of the Ships probably scheduled for Monday December 8th. In that case all the ships voids would have been opened up on Friday June 6th to be ready for the Monday inspection.
The ships logs for battleships such as Maryland, West Virginia and others in port would show that condition. He is convinced that the Japanese had all that info and that is why they picked December 7th. So anything you can find will keep him happy I suspect.