[yourapostasy]

We don't have adequate wartime data to know for sure one way or the other. Historically, there has only been one underwater combat engagement between submarines [1] openly acknowledged (there might be classified engagements). However, even generously accounting for all submarine lost at sea accident reports as hostile engagements doesn't yield sufficient numbers of engagements to know what would happen with today's subs between each other in open warfare.

Let's hope it stays that way indefinitely.

[1] https://nationalinterest.org/blog/the-buzz/the-true-story-th...