I wonder how much stealth technology that the Swedes are using came from our silent propulsion secrets those bastards at Toshiba sold Russia?
Did they sell sub propulsion secrets? I thought it was the sale of a CNC milling machine.
Very little, if any. The Swedes have the capability to develope quieter screws themselves. But what makes this sub so dangerous is it's engines. They are quiet, like a diesel-electric on batteries, but can stay down a long time, and make long moderately fast runs, without having to surface, like a nuke boat. Not quiet so or long or so fast, but long enough and fast enough. Especially in the littoral areas.
The Swedes aren't the only ones going AIP. The Italians, the Japanese and the Germans are as well.
It has a Sterling engine (http://en.wikipedia.org/wiki/Stirling_engine) - very quiet and efficient. The US navy has one leased from Sweden for a month at the Pt. Loma sub base to study ways of detecting subs utilizing this propulsion technology. In war games it came close enough to the Reagan to photograph it which counts as a kill.