PORTSMOUTH NAVAL SHIPYARD
The Navy's oldest yard — submarine overhaul and modernization since 1800.
OVERVIEW
Portsmouth Naval Shipyard (PNSY) is the oldest continuously-operating shipyard in the U.S. Navy, established in 1800 on Seavey Island in the Piscataqua River. Despite its name, the shipyard is physically located in Kittery, Maine, with the city of Portsmouth, New Hampshire, across the river to the south. The shipyard occupies about 297 acres and employs roughly 7,000 federal civilians and active-duty military personnel.
PNSY is one of four public Navy shipyards under Naval Sea Systems Command (NAVSEA) and the East Coast center for the overhaul, repair, refueling, and modernization of the Navy's nuclear-powered fast-attack submarine force. Los Angeles-class (SSN-688) and Virginia-class (SSN-774) submarines from the Atlantic Fleet rotate through Portsmouth for engineered overhauls and depot-level maintenance availabilities, with the shipyard's reactor-qualified workforce executing nuclear plant work, hull-and-mechanical-systems modernization, and combat-systems upgrades. PNSY no longer constructs submarines — its last new construction, USS Sand Lance, was launched in 1971 — but its overhaul mission has grown steadily as the Navy's fast-attack submarine force has aged.
KEY FACTS
- MissionOverhaul, repair, refueling, and modernization of Los Angeles- and Virginia-class fast-attack submarines
- Founded1800 — the oldest continuously-operating shipyard in the U.S. Navy
- LocationOn Seavey Island in Kittery, Maine, despite the "Portsmouth" name (Portsmouth, NH is across the river)
- SpecialtyNuclear-powered fast-attack submarine maintenance
- ParentNaval Sea Systems Command (NAVSEA)
HISTORY
Portsmouth Naval Shipyard was established in 1800 as one of the original six U.S. Navy shipyards authorized by Congress, and is the only one of those original yards still operating in the same location today. Through the 19th century the yard built and repaired wooden sailing warships and, after the Civil War, transitioned to iron and steel hulls. PNSY built its first submarine, the L-8, in 1917, and submarine construction quickly became its specialty. Through the 1920s, 1930s, and 1940s the shipyard designed and built more than 70 fleet submarines, including many of the boats that played decisive roles in the Pacific submarine campaign of World War II.
The shipyard also became a venue for international diplomacy. In 1905, President Theodore Roosevelt arranged for the peace negotiations ending the Russo-Japanese War to be conducted at Portsmouth Naval Shipyard. The resulting Treaty of Portsmouth was signed at the yard in September 1905, and Roosevelt was awarded the Nobel Peace Prize the following year for mediating the treaty.
After World War II, Portsmouth shifted to nuclear submarine work and constructed several early nuclear-powered submarines. The yard's last new submarine construction, USS Sand Lance (SSN-660), was launched in 1971, after which Portsmouth transitioned to its current role as a submarine overhaul, repair, and modernization yard. The shipyard survived several rounds of base closure consideration in the 1990s and 2000s, and remains an essential element of the Navy's fast-attack submarine maintenance enterprise.
MAJOR COMMANDS & TENANT UNITS
- Portsmouth Naval Shipyard (NAVSEA host command)
- Submarine Squadron Detachment
- Naval Sea Systems Command (NAVSEA) — parent command
- Defense Logistics Agency Distribution Portsmouth
LOCATION & GEOGRAPHY
NOTABLE EVENTS
- 1800Shipyard EstablishedPortsmouth Naval Shipyard established by Act of Congress as one of the original six U.S. Navy shipyards.
- 1905Treaty of PortsmouthThe Russo-Japanese War peace treaty was negotiated and signed at Portsmouth Naval Shipyard, ending the Russo-Japanese War. President Theodore Roosevelt won the Nobel Peace Prize for mediating the treaty.
- 1917First Submarine BuiltPNSY built its first submarine, the L-8, beginning more than a century of submarine construction and overhaul.
- 1971Last Submarine LaunchedUSS Sand Lance (SSN-660) was the last submarine constructed at Portsmouth; the yard subsequently transitioned to a submarine overhaul-only mission.