As a former sub sailor let me just say that these things are going to happen. Your role, when sailing around beneath the sea is to not be found and there are no giant picture windows on the front of your vessel like there were in "Voyage to the Bottom of the Sea".

Almost all navigation is done through passive sonar. As soon as you ping actively you give away your own position. You coast around in areas you know are sufficiently deep enough not to run into the bottom listening for the sounds of other vessels. In most cases those vessels sound like a freight train coming through and it's easy to know where they are. However, modern submarines are designed to contain all their noise through intense sound reduction programs that involved things such as precisely engineered propellers (the Americans had a huge edge on that until recently when the precision machining technology got away from us) to sound dampening mounts on every motor and mechanical device on board. I'm certain since I left that active acoustic reduction systems like you see in headphones today is now utilized.

In addition, no matter how noisy a submarine might be, the ocean plays games with trying to track them. Temperature inversion layers near the surface can substantially block sound to other depth layers. In every exercise our sub engaged in with surface ships, they never found us. The only time they did was a collision our sub had with a destroyer that caused our boat to limp back into port with all the masts bent back. (I watched it come in from a damage control school I was at that day.)

I saw a sub come back into port in Pearl Harbor with its entire conning tower stripped off and heard tales of the Russian sub that it had collided with. It wasn't so lucky. They heard it going down and imploding. Somehow that story never made the headlines.

Perhaps subs need a huge red-tipped white cane extending out in front of them.

Art