[WildTurkey]

agreed it's amazing it made it home but I was under the impression subs are designed to "compartmentalize" in sections to ward of damage and water taking the whole thing down.

You are correct and in this case the "pressure compartments" were not breached. However, the compartmentalization was never perfect and has gotten worse with newer designs. Even in the old 637 class, a certain amount of flooding aft would result in such a trim level (nose up) that the ballast tank effectiveness was severely diminished.

[Paul_Denton]

However, the compartmentalization was never perfect and has gotten worse with newer designs.

How is that? more penetrations through the bulkheads?