South Boston Naval Annex Building 16 – History

Building 16 resides in the former South Boston Naval Annex, now the Raymond L. Flynn Marine Industrial Park, and what is currently being rebranded as the “Seaport District” of Boston. The annex was a 167 acre extension of the Charlestown Navy Yard constructed on the Commonwealth Flats, an area of mud flats across the harbor from what is now Logan Airport. It’s history is inextricably linked to Drydock 3, one of the major features of the Naval Annex which is still in operation today.

Development of the area in South Boston was approved by the Directors of the Port of Boston in 1912. Construction of the Commonwealth Dry Dock was approved in 1914 with construction actually starting in 1915. The Navy took an interest in the drydock as part of a huge expansion of it’s footprint in the greater Boston area and the 1918 Naval Appropriations Act provided funding for a 6 year lease of the facility. The importance of the drydock to the Navy seems to have escalated rapidly and on October 17, 1918 funding was approved for the Navy to purchase the property. On April 28, 1920 the Navy purchased 101 acres of land for $4.3 million and designated the facility Dry Dock 3.

The South Boston Naval Annex continued to expand and in 1940 the Navy received approval to fill in part of the annex to construct additional jetties. A frenzy of expansion and additional construction began. Building 16 was completed in January of 1941 to serve as a machine shop.

In July 1941 the Navy took over Pier 5 which, today, houses the Seaport World Trade Center. The same month, the Commonwealth of Massachusetts donated an additional 69 acres to become part of the naval annex. By September 1941, construction of Piers 1 and 2 was completed. As soon as they were complete, additional work was started to extend them, as well as construct Piers 3, 4, and 7. In February 1942, the facility was designated U.S. Navy Dry Dock, South Boston.

An aerial photograph from 1943 (source: shows the massively expanded complex. Building 16 is the building at the bottom-center of the image, just next to the building with the dark roof.

In 1943, the Kaltenbach corporation delivered two portal cranes to the facility. Crane 90 was allocated to dry dock 3, and continues to operate today. Crane 91 was allocated to Dry Dock 4. Crane 91 began service in the other drydock facility February 10, 1944.

After the end of WWII, 9 different buildings within the dry dock facility were demolished, but Building 16 remained.

Reduction in the size of the Naval facility continued and on July 27, 1954 congress authorized a lease of portions of the adjacent U.S. Army facility to the Port of Boston Commission. Throughout the 1950s, additional land was leased to the Commission or sold off. The largest tenant of the annex, the Boston Group, Atlantic Reserve Fleet, was disestablished in 1961. Also in 1961 several of the Naval facility’s jetties were re-designated Wharves 105 – 108. In 1964 the “South Lean-to” of Building 16 was demolished.

In 1970, the 58 acres housing the Boston Army Base was transferred back to the Navy, only to be declared excess to the Navy’s needs in 1972. Portions of the property seem to have fallen into and out of the military’s hands during this time. In June 1972 the Army actually requested the return of it’s land. The same month, Piers 1, 3, 4, 7, 8, and 109 were inactivated. By January 1975 13 acres were transferred back to the Army.

November 21, 1973 saw the beginning of the inactivation of Drydock 3. At the same time, the Coast Guard expressed an interest in moving their base, located in the North End of Boston, to the former Navy facility. However, the plan never came to fruition and was abandoned by July 1975.

Inactivation of Drydock 4 began on January 8, 1974. The Economic Development and Industrial Corporation of Boston (EDIC) officially took over ownership of the area and changed the name to the Boston Marine Industrial Park in 1975. They almost immediately entered into a one year lease of Drydock 4 to Braswell Shipyards. Braswell soon went out of business, but the dry dock (including piers 5 and 6) were leased to their final tenant, General Ship, in 1981. Long term leases of land and buildings, including the North Jetty and Piers 1-4, were entered into with Massport.

Despite the heavy redevelopment of the South Boston Waterfront and portions of the Marine Industrial Park from the late 2000s and continuing to the time of this writing in 2021, the area where building 16 sits is still fairly industrial and underutilized.

There is an incredibly detailed history of both the South Boston Naval Annex and the Charlestown Navy Yard on the National Park Service’s website at More photos can be found in another document on NPS’ website at

Check out my second post on Building 16 for more of my pictures and stories of visiting, as well as an update on Building 16’s ultimate fate!