PNSY Successfully Undocks Cheyenne 2025-02-10 Comments Closed News, RSS KITTERY, Maine — The Los Angeles improved-class attack submarine USS Cheyenne (SSN 773) was successfully undocked Feb. 6, marking a significant milestone in its service life extension program at Portsmouth Naval Shipyard. Related Items Mexican Navy Training Vessel Hits New York’s Brooklyn Bridge. Some Injuries Reported 2025-05-18 How veterans are faring in the 2024 election 2024-11-05 U.S., the Philippines Conduct Maritime Cooperative Activity 2025-07-18 Strengthening Alliances Through Learning, NPS Hosts European International Alumni Symposium 2024-10-29