The UK Ministry of Defence’s Salvage and Marine Operations (SALMO) Delivery Team has awarded a follow-on in-service support contract worth £3,044,858 to HII Unmanned Systems Inc, extending sustainment arrangements for the Royal Navy’s REMUS 100 and REMUS 300 unmanned underwater vehicle (UUV) fleets.

The contract – awarded with HII as the sole bidder and recorded as an SME award – covers project management, technical support, repairs, training and maintenance. It follows on from contract activity placed earlier this year and secures continuity of availability for two of the Royal Navy’s most heavily utilised autonomous underwater platforms.

REMUS 100 and REMUS 300 systems are central to UK mine countermeasures, hydrographic survey, port security and ISR tasking, and underpin the Royal Navy’s shift away from traditional crewed minehunters under its Mine Hunting Capability (MHC) programme.

Backed By A Doubled UK Footprint

The award lands shortly after HII confirmed it has doubled the size of its unmanned systems facility in Portchester, Hampshire — significantly increasing UK-based capacity to support REMUS operators across the Royal Navy and wider European customer base.

The expanded Portchester site now serves as the European hub for HII’s Mission Technologies division, delivering maintenance, training, logistics and sustainment, and is being readied to support the ROMULUS family of unmanned surface vessels from 2026. Activity also spans AI, C5ISR, electronic warfare and fleet modernisation. For UK supply chain stakeholders, the bigger footprint means deeper localisation of support, reduced transatlantic logistics dependency and faster turnaround for Royal Navy users.

Strategic Context

HII is the world’s largest UUV manufacturer, having delivered REMUS systems to 30 countries including 14 NATO members. The unmanned sea systems market is forecast to grow at 13.78% CAGR between 2025 and 2030 (Mordor Intelligence), driven by rising investment in undersea warfare and seabed infrastructure protection.

With HII formally classified as an SME for this award and its UK presence growing, the follow-on contract points to an expanding pipeline of UUV sustainment and modernisation opportunities for British tier-two suppliers and specialist engineering partners supporting the Royal Navy’s autonomous future.

Image: MOD Copyright