HII has completed base-year production of its Lionfish small unmanned underwater vehicle (UUV) for the US Navy, marking a key milestone in the service’s effort to expand autonomous undersea capabilities.
The program, awarded in 2023, supports critical undersea warfare requirements as the Navy integrates dedicated autonomous systems with crewed platforms, including Virginia-class submarines. HII finalized production of 42 Lionfish hulls in December, following the earlier delivery of two vehicles in April 2025.
Manufacturing of the Lionfish fleet is scheduled to continue through 2028, with contract options allowing for the production of up to 200 systems. Program-related activities are being carried out at HII’s facility in Pocasset, Massachusetts.
Lionfish is derived from HII’s proprietary Remus 300 UUV, which features an open-architecture design to accommodate future mission upgrades and payload integration. Depending on configuration, the Remus 300 is approximately 3 meters (10 feet) in length and weighs about 70 kilograms (154 pounds).
The platform offers a range of up to 165 kilometers (103 miles), a cruising speed of around 5 knots, an operating depth of up to 1,000 feet (305 meters), and a recharge time ranging from 6 to 18 hours.
The US Navy selected the Remus 300 as the basis for the Lionfish program in 2022 after successful evaluations, replacing the Swordfish UUV fleet derived from the earlier Remus 100 design.
