A history lesson that needs to be learned and understood.

How did this accident even happen? Some articles in the press characterized the subs as having been involved in a cat-and-mouse game that had gone too far. Indeed, such games were common between the attack submarines of rival nations, and had resulted in collisions in the past.

However, that account remains unlikely because a submarine can only play a cat-and-mouse game if it is able to detect the other ship. And in the shallow waters off of Kildin Island, it is unlikely either vessel could.

It’s tempting to think of sonar as a sort of radar that works underwater. However, water is a far less compliant medium than air even for the most modern sensors, and wind conditions, temperature variations and sounds rebounding off the ocean floor can all dramatically degrade its performance. When attempting to detect the extremely quiet submarines currently in use, just a few adverse factors can turn a very difficult task into an impossible one.

Therefore, a submarine spying close to an adversary’s home port might not be able to spot another submarine heading towards it until after the collision—which can be worse than embarrassing for everyone involved.

On February 11, 1992, the USS Baton Rouge, a nuclear-powered Los Angeles–class attack submarine, was lurking twenty meters deep in the shallow waters off of Kildin Island, fourteen miles away from the Russian port of Murmansk.