Chain Forge, Building 105

Black and white photo down a street with a tall two-story building that continues down the street.
At the Chain Forge, workers developed new techniques for making anchor chain.


Quick Facts
First Ave, Between Ninth and Thirteenth St.
Site of anchor chain production and development of the "die-lock" process
National Historic Landmark, National Register of Historic Places
Private Building

Built in 1904, the Chain Forge (Building 105) runs along an entire city block of the Charlestown Navy Yard (also known as the Boston Naval Shipyard). As the US Navy faced a new era, it required facilities to support one of the world's largest navies. The Chain Forge and nearby Buildings 104 and 106 all have a similar design and were built together.

At the beginning of the 1900s, the US Navy started replacing its wooden ships with metal ones. Navy architects designed the Forge as a large, spacious factory for making anchors, anchor chains, and other metal products for the Navy. Building 105 has an innovative steel frame, covered with a brick veneer in a Classical Revival style. This "Cathedral of Industry" also has a central, gabled portico flanked by two wings with numerous arched windows.

Though the Forge dominates the interior of Building 105, the building also included space for a power generator, offices, restrooms and even a repair facility for the Yard's railway locomotives.

While Forge workers made ship propellers and any metal item the Navy needed, they became best known for producing anchor chain. Every US Navy ship needs a reliable anchor and anchor chain. The well-known Navy song "Anchors Away" pays homage to that basic part of a successful mission, a working anchor and chain. Previously during the Age of Sail, Navy sailors used rope to help anchor ships, rope that was made in the Charlestown Navy Yard Ropewalk.

Starting in the 1880s, the Navy relied on the Charlestown Navy Yard for most of its anchors and anchor chains. Initially, this work spanned Buildings 40 and 42 in the Yard. Over the years, workers steadily improved metal anchor chains, but chains still had a flaw: chain links could break apart, sending a ship adrift from its detached anchor.

In its constant search for more reliable anchor chains, the Navy consolidated chain making in Building 105 starting in 1904. Here, Chain Forge Master Mechanics James Reid and Albert M. Leahy with Engineer Carlton G. Lutts invented a method they called "Die-Lock." They devised a nearly indestructible anchor chain that is still unmatched today. Due to the durability of the Die-Lock chain, it became the only anchor chain made by the US Navy after 1928, and most of it was made in the Chain Forge.

Enormous hammers, some with the force of twelve tons, the weight of a city bus, were crucial to the Die-Lock method. These hammers forged anchor chain links that could never break apart. The largest hammer in the Forge sat on its own concrete foundation 35 feet deep to prevent Building 105 from shaking.

To test a new chain for strength, the Forge had another piece of extraordinary equipment called the Tinius Olsen Testing Machine, named for its inventor. This machine subjected a chain to enormous stress. Once tested, the surface of the chain was smoothed, mostly by sandblasting it, and then painted.

Navy Yard workers produced anchor chains in 90-foot lengths called "shots." Making and repairing anchor chains was more manageable in these lengths. These shots, or lengths of chain, are joined together by detachable links which were another unique invention by the staff of the Chain Forge. Anchor chains on Navy ships are 12-15 shots or over 1,000 feet long. In addition to making varied chain lengths, the Forge made different size anchor chains for the Navy’s different sized ships.

Throughout the 1900s, the Navy made structural changes to the Chain Forge to better fit the production needs at the Yard. A variety of ventilation systems populate the roof of the Chain Forge, installed over the years to exhaust the toxic smoke and heat created in the Forge as the Navy expanded production.

In 1943 during World War II (WWII), Yard managers expanded Building 105 with large, rectangular additions on both its north and south sides and covered them with fireproof siding that eliminated some of the original brick veneer. During WWII, the Forge had a staff of 550 people working three shifts, including a small number of women and African Americans.

With its massive machines and fiery furnaces, the Chain Forge could be a dangerous place to work. One of the worst accidents occurred in 1944 when a large anchor chain slipped loose and knocked a worker to the ground, breaking his legs and cracking his skull in the process. This worker survived his injuries.

After over sixty years of service, the Chain Forge was designated a National Historic Landmark in 1966 and it is listed in the National Register of Historic Places. The location of the Chain Forge is also a notable Revolutionary War site: Moulton's Point. Here, British troops from Boston landed in Charlestown to engage in the Battle of Bunker Hill in June 1775. In 1936, workers for the Works Progress Administration (WPA), installed a bronze plaque on Building 105 commemorating the landing site as they performed renovations in the Forge. They installed a related plaque on Building 5 at the same time.

When the Navy Yard closed in 1974, Forge workers were making some of the largest chain it had every produced. At the time, workers forged chain for the nuclear aircraft carrier the USS Eisenhower. Each link was about 30 inches long and weighed 360 pounds. It's still one of the largest anchor chains used in the US Navy.

Over 100 pieces of equipment remained in the Chain Forge in 1974, about 20 of these are considered significant. The Chain Forge was transferred to the Boston Redevelopment Authority in 1978, but not the equipment. In 2001, the U.S. Army Corps of Engineers refurbished this equipment and removed hazardous materials from Building 105.

The Chain Forge and its innovative workforce helped the Navy solidify its place as one of the world’s top three navies. Forge workers devised anchor chains that are still renowned for their strength and durability, and they were the main supplier of these chains to the U.S. Navy from 1904 to 1974 during two World Wars and the Cold War. Their work took place in a uniquely designed vaulted spacious factory that workers updated to better fit their needs.

Building 105 is now privately owned and there are plans to convert it into a hotel or residential housing. There are also plans for the building to house some of the Chain Forge equipment, particularly the hammer with the twelve-ton force, nicknamed the "Mighty Monarch." The equipment will give the public a glimpse into the storied past of the Chain Forge, as told by staff of the National Parks of Boston. Some of the Chain Forge story can be seen in the Charlestown Navy Yard Visitor Center (Building 5) in an exhibit called "Serving the Naval Fleet." Huge anchors made in the Forge can still be seen on the grounds of the Charlestown Navy Yard.

Learn More...

Charlestown Navy Yard: Chain Forge


  • Carlson, Stephen P. Charlestown Navy Yard Historic Resource Study, Vol 1-3. Boston, MA: Division of Cultural Resources, Boston National Historical Park, National Park Service, U.S. Department of the Interior, 2010.
  • Carolan, Jane, Charissa W. Durst and Roy A. Hampton. Historic Structure Report for Chain Forge (Building 105), Charlestown Navy Yard, Boston National Historical Park, 2012.
  • Christianson, Justine. Historic American Engineering Record Charlestown Navy Yard, Chain Forge (Smithery) (Building 105). HAER No. MA-90-3, National Park Service, U.S. Department of the Interior, 2014.
  • Ivas, Peter 2018 Let's Take a Trip 1956. Video. [Accessed December 2020].
  • Raber, Michael et al. Special Resource Study, Chain Forge Machinery in Building 105, Boston National Historical Park Charlestown Navy Yard. Boston Preservation Alliance 2014.
  • Wonder Drug Saves John White's Life After Yard Accident, Boston Navy Yard News, February 24, 1945.

Boston National Historical Park

Last updated: January 18, 2023