US defence firm HII has doubled the size of its unmanned systems facility in Portchester, Hampshire, strengthening its long-term presence in the UK and positioning the site as a European hub for autonomous maritime operations.
The expanded facility will support the Royal Navy and European partners operating HII’s REMUS family of unmanned underwater vehicles, while also preparing for the introduction of the company’s ROMULUS uncrewed surface vessels, which are scheduled to enter service from 2026.
HII said the enlarged Portchester site will significantly increase its capacity to support UK and allied customers. The company described the expansion as a move to bring operational, technical and sustainment expertise closer to European users, reducing reliance on US-based support for deployed systems.
Duane Fotheringham, president of Mission Technologies’ Unmanned Systems business group, said the investment reflected a long-term commitment to the UK. “This new HII Portchester facility reinforces HII’s long-term presence in the United Kingdom and provides a strong foundation for future cooperation,” he said. “It ensures that UK and European operators, suppliers, and partners of ROMULUS USVs and REMUS UUVs receive regional access to world-class support, training, and sustainment.”
According to HII, the Portchester facility will also serve as a European hub for its Mission Technologies business, supporting collaborative activity with US Combatant Commands and allied forces. The site will provide support for electronic warfare and C5ISR integration, artificial intelligence-enabled systems, fleet modernisation and live, virtual and constructive training.
The company said the expansion will be staffed by UK employees and is expected to support new jobs, supplier engagement, maintenance activity and long-term sustainment for operators across the UK and Europe. HII added that the site will work in close coordination with its global engineering, production and mission support teams.
Royal Navy partnership
The Royal Navy has operated REMUS systems for more than two decades, having first acquired REMUS 100 vehicles in 2001 for mine countermeasure operations. Since then, the Ministry of Defence has also introduced REMUS 300 and REMUS 600 variants, expanding the fleet’s capability in seabed survey and underwater reconnaissance roles.
In 2024, HII announced the sale of additional REMUS 100 and REMUS 300 vehicles to the Royal Navy, a deal the company said reflected confidence in the platform’s upgrade potential and durability. HII notes that more than 90 per cent of REMUS vehicles delivered globally over the past 23 years remain in service.
The Portchester expansion also builds on a memorandum of understanding signed in September between HII and Babcock International Group. Under the agreement, HII’s REMUS vehicles are to be integrated with Babcock’s submarine Weapon Handling and Launch Systems, enabling autonomous launch and recovery of unmanned underwater vehicles through submarine torpedo tubes.
HII said the partnership builds on recent US Navy trials. “The collaboration follows the US Navy’s first successful forward-deployed torpedo-tube launch and recovery of a UUV using a REMUS,” the company said, adding that the aim is to strengthen allied undersea advantage.
Babcock’s Weapon Handling and Launch Systems are already in service with submarine fleets in the UK, Canada, Australia, Spain and South Korea.
Preparing for ROMULUS
The expanded Portchester site will also support the deployment and sustainment of HII’s ROMULUS family of uncrewed surface vessels. ROMULUS is a modular, AI-enabled design powered by HII’s Odyssey Autonomous Control System, with the lead variant, ROMULUS 190, currently under construction and sea trials planned for 2026.
HII describes ROMULUS as purpose-built for extended autonomous operations, with commercial-standard hulls intended to support rapid and repeatable production. Larger variants are capable of carrying multiple ISO containers and supporting missions including intelligence, surveillance and reconnaissance, mine countermeasures, counter-uncrewed systems, strike support and launch and recovery of unmanned systems.
The company said the Portchester expansion reflects rising European demand for autonomous maritime systems. “The expanded facility will operate as a strengthened regional hub for HII’s unmanned systems,” HII said, “supporting operators as they deploy, sustain and integrate autonomous capabilities across the UK and Europe.”
Thia comes as the Royal Navy and NATO allies place increasing effort on uncrewed systems to address force structure pressures, rising undersea threats and the growing requirement to protect critical seabed infrastructure across the North Atlantic and High North.
So, is this DIP stealth, instalment announcement?
No, it only says sea trials for 2026 so it isn’t saying the RN have decided to buy them already.