Groton — In his pocket, Henry Nardone always carries a worn index card with a list of important dates in the life of the USS Nautilus.
Nardone wants to make sure he never forgets any of the milestones on a project he considers the highlight of his career. He was a naval officer assigned to the supervisor of shipbuilding office at Electric Boat when the Nautilus, the world's first nuclear-powered submarine, was under construction.
"It was a first for the Navy and a first in the world," Nardone, who worked for EB after leaving the Navy, said Thursday at the shipyard. "Not many people get the opportunity to participate in a program like that."
Now 90, Nardone, of Westerly, was one of three men in the audience Thursday with direct connections to what may be the world's most famous submarine as EB commemorated the 60th anniversary of the Nautilus' keel-laying. In the 1952 ceremony, President Harry S. Truman inscribed his initials on the sub.
Standing in front of a recently polished and rehung plaque that marks the spot of the keel-laying ceremony, EB President Kevin J. Poitras said the Nautilus revolutionized naval warfare and proved pivotal to the future of the shipyard.
"For the last 60 years, the common thread running through Electric Boat's progression of submarine innovation has been USS Nautilus," he said.
JJ Kelley, 83, of East Lyme, participated in the submarine's last major repair period and retired from EB as director of nuclear quality control. Kelley said he went to Thursday's ceremony to remember a key event in the history of EB.
Also in attendance was Paul Tranchida Sr., 96, of Groton, who made the torpedo tube doors for the Nautilus while working in the shipyard foundry.
Tranchida said he was the only one allowed to make those doors; he still considers them his doors.
Poitras said he didn't know where the shipyard would be today if it hadn't been challenged to apply nuclear energy to propulsion. The future looks promising, he said, with EB continuing to build Virginia-class attack submarines under a teaming agreement with Newport News Shipbuilding in Virginia and 1,700 employees working on the design for a new ballistic-missile submarine.
With construction scheduled to start in 2021, the ballistic-missile submarine to replace the Ohio-class boats will be in service until at least 2080, more than 120 years after the Nautilus entered the fleet as the first commissioned nuclear-powered ship in the U.S. Navy, Poitras said.
"You never want to lose sight of the past and how you got here," he said.
The Nautilus (SSN 571) shattered records for speed and distance while submerged and became the first ship to cross the North Pole on Aug. 3, 1958. With speed, endurance and unmatched stealth that only nuclear propulsion could provide, the Nautilus was the most capable warship of its generation, said Lt. Cmdr. Robert W. Sawyer, officer in charge of the Historic Ship Nautilus.
"The success of Nautilus changed the equations that described a superpower," he said. "The other world powers scrambled to join this club."
The sub still serves the country, now as a museum exhibit at the Submarine Force Museum, Sawyer said. Nautilus "continues to educate the public about a legacy of vision and pioneering," he said, "while inspiring youth to build the dream."