A couple of posts ago, I reviewed a book by Mark Joseph entitled Typhoon. is even better. Set during the height of the Cold and Vietnam Wars when nuclear tensions were at their peak, it tells the very realistic and frightening story of a collision between the Barracuda, an American nuclear attack submarine, and a super secret Russian nuclear sub that has very new and sophisticated capabilities.
The Barracuda has been assigned the task of hunting an American aircraft carrier during war game exercises. The Russian sub has been shadowing the task force pretending to be another American sub by masking her own noises by simulating those of a known sub. The Russian sub driver, after realizing he has been "outed" by the Barracuda wants to leave the area before more can be learned about his sub's secret capabilities. The political officer disagrees and takes over command He reverses the prop grazing the Barracuda, which had been following in the Russian sub's baffles. The Barracuda is forced to surface but not before its sonar operator hears sounds of the Russian sub descending way past nominal test depth and breaking up. At least that's what they think.
Collisions between submarines is not fanciful idea. In 1998 two U.S. nuclear subs collided off Long Island. (link) Blind Man's Bluff, by Peter Huchthausen, a book I read several years ago, is the non-fictional account of U.S. submarine espionage. Huchthausen reports several incidents of cold war submarines colliding, one that may have even resulted in the loss of a U.S. sub. Huchthausen, by the way, also wrote a fascinating account of the Cuban Missile Crisis from the decks of a U.S. destroyer where he was a junior officer. (October Fury) It's combination a thrilling memoir/history of Russian submarine actions and U.S. counter measures during that frightening October, 1962.