Ok, I argue with someone on another forum.
He said an engagement between two subermeged SUB IS impossible in WW2 and in real life.
So the

question is:
Is it possible for submarines from WW2 engaging another sub while submerged in real life?
True, i am not informed if there was a fight. Nothing has proven this case is impossible.
Nothing has proven this is possible. Well until now, i didn't find any source which prove me that. Unless, I have been smacking my head.
But he kept using his talent of sophist to try and convince me. What a tough guy.