A key element of a $1.7 billion modernization effort at Portsmouth Naval Shipyard has been utilized for the first time.
Navy officials said Friday that the USS Cheyenne became the first submarine to enter Dry Dock 1 without buoyancy assistance last month.
The so-called super flood basin is akin to a navigational lock that upgrades the shallowest of the shipyard's dry docks.
The system allows allowing submarines to enter independent of tides and without buoyancy.
It'll also support Virginia-class submarines in addition to Los Angeles-class submarines like the Cheyenne.