Seawolf Class submarine

Seawolf Class  is in service with US Navy. Its a nuclear powered submarine with destructive weapons. It is also known as the fast attack submarine because of its swiftness. Its the most expensive submarine in the history. 
The last Seawolf Class  was built in the year 2005. Three this type of submarines are now active in the service of US Navy and about 25 are cancelled.
Seawolf Class submarine is built as to no chance of lose. It had helped US Navy in many secrete missions.
Now some of the old models of Seawolf Class submarine have now been modified or converted to Spy Submarine which is also a very dangerous Submarine in the US Navy service.