4 ms·

That suggests they are hard to find, if they can't even see each other?

• arethuza 13y ago
  From the Wikipedia page for the French-UK incident: 'Hervé Morin, France's Minister of Defence, said that they "face an extremely simple technological problem, which is that these submarines are not detectable".'
• dTal 13y ago
  On the contrary. If they were just wandering randomly around the oceans, you would expect collisions between two subs to be impossibly rare. In fact it's known that, at least during the Cold War, nuclear subs often played cat and mouse games with each other, using passive sensor technologies to stalk each other to keep tabs on them. Every now and again though someone slams on the brakes or makes an unexpected turn and bam, collision. Obviously very embarrassing for all concerned, and I wouldn't be surprised if it happens more often than we hear about, and only incidents with serious damage get reported.