U.S. Navy orders 188 more torpedo-armed mines to hunt submarines

The U.S. Navy has placed its biggest order yet for an underwater weapon nobody has ever seen and designed to sit silently on the seafloor for months, waiting for an enemy submarine to wander close enough to torpedo without warning.

General Dynamics Mission Systems, based in Taunton, Massachusetts, has been awarded a $229,658,178 contract modification to deliver 188 additional Hammerhead units along with eight sets of complementary support equipment, according to a Department of War contract announcement. Hammerhead is a moored anti-submarine mine, a weapon that anchors itself to the seafloor at intermediate to deep-water depths and waits, using acoustic sensors to listen for the distinctive sound signature of an approaching submarine rather than exploding on simple contact like a traditional naval mine.

Once Hammerhead’s sensors confirm a genuine hostile target, the system releases an encapsulated MK 54 lightweight torpedo, modified for underwater launch, which then independently homes in on and strikes the submarine, giving the weapon the ability to discriminate between actual threats and passing marine life or friendly vessels rather than blindly detonating whenever something swims nearby.

The concept behind Hammerhead is not new, even though the technology inside it is thoroughly modern. The weapon traces its lineage directly back to a Cold War-era system called CAPTOR, short for encapsulated torpedo, which the Navy first tested in the 1970s and armed with an older MK 46 torpedo capable of operating at depths up to 1,000 feet (305 m). The Navy retired the MK 60 CAPTOR mine years ago, and Hammerhead is designed specifically to replace that lost capability with a modern sensor package and the more capable MK 54 torpedo, extending the weapon’s effective operating area and giving the Navy a renewed tool for restricting or denying an adversary’s access to strategically important underwater terrain, including chokepoints, deep-water anti-submarine barriers, and contested coastal waters.

Today, Hammerhead deploys from surface ships and submarines, but the Navy has made clear it wants the weapon to eventually launch from unmanned underwater vehicles as well, letting the system be planted covertly without exposing a crewed vessel to the area being mined. That ambition connects Hammerhead to a broader family of underwater mining programs General Dynamics has developed for the Navy in recent years, including MEDUSA, short for Mining Expendable Delivery Unmanned Submarine Asset, a torpedo-tube-launched robotic vehicle built to secretly plant mines from American submarines, which received its own $13.97 million contract modification in July 2026. Congressional researchers have specifically identified Boeing’s Orca extra-large unmanned underwater vehicle, an autonomous submarine roughly the size of a subway car, as a potential future launch platform for Hammerhead, a pairing that would let the Navy quietly seed minefields across contested waters without ever putting a crewed vessel at risk during the deployment itself.

This latest $229.6 million order represents a substantial escalation over General Dynamics’ earlier Hammerhead contracts. The company originally won a $92.9 million contract in September 2021 to design, test, and deliver Hammerhead prototype units, followed by a $20.7 million modification in 2024 to exercise a production option and additional smaller orders since then. Reporting from USNI News in March 2026 indicated the Navy was seeking to increase Hammerhead production specifically to meet operational requirements officials wanted satisfied by late 2026, and that same contract modification revealed the government’s intent to procure a Hammerhead technical data package, a move that would give the Navy the underlying engineering documentation needed to potentially open future production to other defense manufacturers beyond General Dynamics alone.

Work under the new 188-unit order will spread across five locations, with the majority, 55 percent, performed at General Dynamics’ facility in Taunton, Massachusetts, followed by 15 percent in Braintree, Massachusetts, 13 percent in Lincoln, Nebraska, 10 percent in Wilmington, Massachusetts, and 7 percent in Accident, Maryland. That geographic spread reflects the specialized supply chain feeding into a single sophisticated underwater weapon, with different facilities likely handling distinct components such as sensors, torpedo integration, and the mine’s structural housing. The Navy expects the work to be completed by October 2028, giving General Dynamics roughly two years to manufacture and deliver the full order.