According to Swedish newspapers, in training exercises-war games- the SSK Gotland (currently leased to the US Navy) has sunk most sophisticated nuclear submarines. But perhaps even more disconcerting, it reportedly sunk largest aircraft carrier in the USN, the U.S.S Ronald Reagan -CVN-76
Officially say:She's really run rings around our carrier groups
The Pentagon said it believes the greatest undersea threat facing the U.S. Navy since the end of the Cold War has arrived. The threat is real. And it has the Navy so concerned that it's turning to Sweden for help. That's because the Swedes have those silent submarines.
The threat involves a new a new class of silent submarines -- subs that the U.S. Navy is having trouble finding under water. In this exclusive investigation, NBC4's Chuck Henry looked into one of those submarines in San Dieg
They came to San Diego because the Navy is worried about this new generation of silent subs.
The Pentagon leased the Gotland for one year, but now has extended the lease for a second year, as they try to learn why this submarine so difficult to find underwater.
When the Gotland wants to be silent and undetectable, especially along coastal waters, there's not a place it can't go. And that's one of the reasons it's here.
Since last summer the Navy has spent months playing a game of cat and mouse with the Gotland off San Diego, and time after time the Swedish sub has eluded its pursuers.
Although this emerging undersea threat is a top priority for the U.S. Navy, the U.S. is committed to its nuclear submarine force, and has no plans to develop subs like the Gotland.
The Navy says it just wants to know how to detect and kill them.
3 submarines Gotland Class (Type A19) , and 2 submarines of the Vastergotlnd Class (Type A17) are currently in service in the Swedish Navy.all of them with a (Striling) air-independent propulsion system (AIP), which extends their endurance from a few days to several weeks.
http://www.nbc4.tv/news/10116514/detail.html
about Gotland Class see below links
http://www.naval-technology.com/projects/gotland
http://en.wikipedia.org/wiki/Gotland_class_submarine