HII has marked a significant milestone by completing the final base-year production of its Lionfish small unmanned underwater vehicle designated for the US Navy. This program, which was initiated in 2023, addresses critical undersea warfare requirements as the Navy integrates advanced autonomous capabilities into its crewed vessels, notably the Virginia-class submarines.
As of December, HII successfully delivered a total of 42 hulls of the Lionfish system, with two of those drones being handed over in April 2025. The company’s commitment extends through 2028 with plans to manufacture additional units for the Navy, potentially scaling production up to 200 platforms.
Production activities are taking place at HII’s facility in Pocasset, Massachusetts, where the team is geared toward supporting the Navy’s evolving needs in undersea operations.
The Lionfish is built on HII’s proprietary Remus 300 underwater drone, designed with an open architecture to allow for adaptability to future requirements. Depending on its configuration, the Remus 300 spans approximately 3 meters (10 feet) in length and has a weight of 70 kilograms (154 pounds). The vehicle boasts an impressive operational range of up to 165 kilometers (103 miles) and can achieve speeds of 5 knots (approximately 9 kilometers per hour). It can operate at depths of up to 1,000 feet (305 meters) and typically requires between 6 to 18 hours for recharging.
In 2022, the US Navy chose the Remus 300 for the Lionfish program after it successfully passed rigorous evaluations to succeed the service’s Swordfish underwater drone fleet, which was based on HII’s older Remus 100 model. This transition reflects the Navy’s emphasis on enhancing its technological edge in underwater combat scenarios.
