The DSRV (Deep Submergence Rescue Vehicle
) was the brainchild
of John P. Craven who was responsible for, among other things, a phone tap
of an undersea Russian
communications line and the stealing of a sunken Russian Kilo Submarine
The DSRV is a mini-sub capable of reaching very deep waters, supposedly to rescue to crew of a downed submarine. However this concept is impossible, the first DSRV was a government and CIA cover-story for covert operations.
The reason that a deep sea rescue vehicle would not work is simple: the rescue sub only has to be able to go as deep as the ship it was sent to rescue. Submarines are rated to what is called crush-depth. Crush-depth is where the enormous pressure of the surrounding water causes the hull of the submarine to buckle inward in an implosion. Even the multiple-titanium-hulled Typhoon (Russia) with a maximum diving depth of 500m would be crushed unless it had the good fortune to go down on a continental shelf or a seamount. The depth of most of the worlds oceans is between two and four miles, far deeper than the crush-depth of any military submarine (except the DSRV).
The only reason the US would want a manned submarine to go that deep under the pretences of a rescue would be to take a look around a wreck to 1) make sure there are no sensitive materials that could be recovered by another country (if it was a US boat) or 2) to recover any sensitive materials from some other countries sub.
The first DSRV was a mock-up that was welded to the back of the USS Halibut. The Halibut was used for the infamous Russian cable tapping operation. There are well documented pictures in the popular media showing the Halibut steaming on the surface out of port with the false DSRV on her back. The Navy made sure everyone knew the “DSRV” was for international rescue missions. In fact it was nothing more than an airlock to let Navy divers out of the submerged submarine to retrieve the tapes from the listening operation (before the false DSRV the divers had to go in and out through the torpedo tubes).
The DSRV is only useful to rescue sailors from other deep-sea submarines or recovering parts from a dead sub on the deep ocean floor.
The Kursk was reachable by DSRV, but a deep-sea vehicle was not needed for the rescue due to the depth of the water. In fact the keel of the submarine was longer than the depth of the water. In other words, if you turned Kursk on her screws her bow would stick up above the water. If the sub went down in deeper waters it would have flooded entireley and/or imploded long before comming to rest on the ocean floor.
Much of this information is from the book Blind Man’s Bluff: The Untold Story of American Submarine Espionage. I recommend this book, it is better than Tom Clancy because all this actually happened.