Did a U.S. sub torpedo the Kursk?

As far as collisions go, they were a lot more common than you realize. The Soviet sub captains would do a manuver called a Crazy Ivan, where they would snap around in a circle to look behind them, since a sub can't see straight behind them. If a US sub was doing ELINT work and following them the only thing they could do was to stop the prop, and coast and hope to stop in time. Anything else and they would make noise and be detected. If they were following too closely, they sould go right into the back of the Soviet sub. They usually didn't cause much damage to either sub. As far as the Kursk though, I really don't think that an LA could have hit her hard enough to cause enough damage to sink her and still be able to make it to a port in Norway. The Oscar was a much bigger sub than the LA is weight wise.