USS Seawolf (SSN-575) , a unique submarine, was the third ship of the United States Navy to be named for the seawolf , a solitary fish with strong, prominent teeth and projecting tusks that give it a savage look, was the second nuclear submarine, and the only US submarine built with a liquid metal cooled ( sodium ) nuclear reactor .Seawolf was technologically more advanced than her predecessor, USS Nautilus (SSN-571) . Carrying a superheated steam powerplant, rather than a traditional saturated steam plan, reduced the size of the machinery spaces nearly 40%. Her liquid-sodium cooled reactor was more efficient than a water-cooled one, and quieter, but posed several safety hazards for the ship and crew. The phrase "Blue Haze" was often associated with the boat, even though t was only one sodium coolant leak ever noted, and that was while she was fitting out in the yards. Although fully armed, Seawolf , like the first nuclear submarine USS Nautilus (SSN-571) , was primarily an experimental vessel. Seawolf was originally thought of publicly as a 'hunter-killer' sub, but in fact was intended to be a one off test platform for the LMSR reactor and future sonar platforms. Her future uses, however, would include covert operations in foreign waters, the likes of which were never envisioned by Admiral Rickover. Seawolf' s keel was laid down 7 September 1953 by the Electric Boat division of General Dynamics Corporation in Groton, Connecticut . She was launched on 21 July 1955 sponsored by Mrs. W. Sterling Cole, and commissioned on 30 March 1957 with Commander R.B. Laning in command.