There was a maintenance record that crew had recorded some deformations in the shell plates but not the same area as the failure. That was where the 40 mm number came from.
After reading the report supplied by Kennebec, I’m leaning more towards a mix of contributing factors and since Japan has a culture of keiretsu where businesses cooperate together as integrated units and a culture of shunto where business and government maintain good relations, I really doubt anyone is going to be shamed in any of these reports to the degree we see things over here. This culture thing maybe why their computer models are not duplicating the catastrophe.
The pictures of buckling in the report did appear very damning. I’m thinking it was an uneasy mix of big loads, big waves, high speeds, unreasonable schedule demands, lax inspections, combined with a minimal factor of safety. I wonder how quick the decision was made to abandon ship because if all those factors are true, it must really suck to work there.
This article:World’s first development and application of HTSS (high tensile strength steel) with yield stress of 47 kgf/mm2 to actual ship hull structureis interesting - has the diagram Steamer was referring to showing where the HTSS was used.