Today, in a run at March 1940, I had a narrow escape. I put my boat at 120m, but some depth charges inflicted damage, forcing me deeper.
As I remember, the British (like the Japanese) had problems with depth charges that could go deep enough. I looked up the specifics
at this link.
It claims that the maximum depth for DCs in the early war was 300ft/91m. Eventually the design was modified to make it to double that (180m).
How does the game handle this? I can see it both ways: adhering to history is always nice, but there's an argument that this meta-knowledge for the player makes the game too easy. (It's nothing urgent, either way.)
Cheers,
Tortuga