VESSEL REVIEW | Sea Archer – Surveillance and logistics USV capable of long-endurance loitering

Leidos Australia has completed harbour and open ocean trials of Sea Archer, a compact Australian-built unmanned surface vehicle (USV) intended for surveillance, logistics, electronic warfare (EW) and strike missions across the country's northern approaches.

Kevin Quarderer, who leads international science and technology for Leidos Australia, told The Australian in early October that 16 Australian boatbuilders had said they were ready and willing to manufacture the craft. The programme remains company-funded and has no Australian Defence Force contract.

Quarderer also said Sea Archer does not yet have a strike capability.

The 11.2-metre (36.7-foot) USV was designed by Leidos' naval architecture business Gibbs and Cox. Its aluminium hull was built by Oceans Rivers Lakes at Toronto, north of Sydney.

Designed for rapid manufacture and repair

Quarderer said that the hull form has been in use for 30 years. He gave the operating envelope as Sea States one to four, with survival and reduced-performance operation in Sea States five and six.

Harbour acceptance trials took place in Tasmania in March. They were followed by sea trials in the Northern Territory from Darwin's East Arm.

Propulsion comes from twin Cox Marine 300 V8 diesel outboards. Each 4.4-litre (one-gallon), twin-turbocharged V8 is rated 300 hp (220 kW) at 4,000 rpm. Leidos made diesel a design requirement because of its availability through military forward resupply.

"We went with commercial off-the-shelf components so it can be built cheaply,” said Quarderer. “If you are in a battle situation and you need to do repairs, it's relatively easy to grab them off the shelf, versus having to go back for a bespoke, manufactured power plant.”

Leidos said the vessel can reach 40 knots at sprint and cruise at 26 knots. Its nominal range, using a 3,000-litre (660-gallon) tank, is 1,500 nautical miles. The company said fuel makes up a third of the vessel's overall weight.

Zoe Chadwick, who leads Leidos' maritime engineering and technology work, said that the craft can loiter on station for up to 23 days on its standard tank. Trading part of the payload allowance for extra fuel can extend the range by 20 per cent.

The enclosed payload bay can accommodate 900 kg (2,000 lb) and accepts interchangeable main bay modules. Intelligence, surveillance and reconnaissance, EW and logistics are baseline capabilities.

The proposed strike fits for the USV comprise either 16 Innovaero OWL loitering munitions or two Kongsberg anti-ship missiles, each of which weighs 407 kg (897 lb) and has a range of more than 300 kilometres (190 miles).

Compatible with various operating modes

The vessel runs on Leidos’ autonomous vessel architecture (LAVA) and can be remotely controlled or tasked to navigate autonomously. Reported behaviours include leader/follower modes and programmed responses to lost communications.

The sensor fit comprises a Furuno radar; a Starlink uplink; and electro-optical, forward-looking infrared and pan-tilt-zoom cameras, providing 360-degree coverage with AI-assisted tracking of people, buoys, vessels and whales.

Chadwick said multiple USVs can share their EW picture across a network. Leidos and Havoc plan to combine Havoc's collaborative autonomy software with LAVA, with Sea Archer as the starting point. A joint validation planned for the fourth quarter of 2026 will have uncrewed surface and aerial vehicles operating under one autonomy system.

The USV fits inside a standard 40-foot ISO high-cube container. It can be trailered to civilian boat ramps for launch and recovery or carried by C-17 aircraft.

Leidos Australia aims to build each vessel in under three months for US$1 million. Leidos is in discussions with other Indo-Pacific navies and has positioned Sea Archer for the Royal Australian Navy's planned large optionally crewed surface vessel requirement.