actualy the thing is also that the XXI didn t have the need to go as deep as other sub.
Type VII was like a red dot on a hydrophone and even as a red dot it was so slow.
Type XXI was a lot more smouth on a hydrophone and can move faster submerge than the type VII on surface

Do you realize the way a type XXI can do at 120 metters before a depth charge can reach that depth??? You should have use a 100 warheads hedgehog to get one at that depth:rotfl: