SEA secures Krait Array contract from Liquid Robotics

SEA Ltd and Liquid Robotics are continuing their partnership under a new large contract for the KraitArray towed sonar. Is this the key for future ASW forces? 

BLUF: 

• Large contract will see 22 of the SEA KraitArray systems delivered to Liquid Robotics. 
• The arrays will be fitted to the Wave Glider persistent autonomous surface vessel manufactured by Liquid Robotics. 
• Towed arrays coupled to autonomous vessels could provide valuable mass and persistence for hard-pressed navies facing crew and budget short falls. 

Systems Engineering and Assessment (SEA), part of the Cohort Group, has been awarded a large contract for 22 of its KraitArray towed sonars by Liquid Robotics. The towed sonar array will be integrated into the company’s Wave Glider persistent uncrewed surface vessel and “marks an important milestone in the global scaling of anti-submarine warfare (ASW)…and maritime domain awareness payloads for uncrewed platforms,” the December 16 press release states. 

No further details of the contract were provided. But let’s start with a brief introduction to the Wave Glider. The Wave Glider, developed by Boeing subsidiary Liquid Robotics, is a persistent uncrewed surface vehicle (USV) that utilises a unique two-part architecture to achieve indefinite maritime endurance. The system consists of a surface float connected via a flexible umbilical cable to a submerged “wing rack.” It generates forward propulsion by harvesting the mechanical energy of ocean waves; as the surface float moves with the waves, the submerged wings pivot to create thrust. This passive propulsion system is supplemented by solar panels on the float, which power onboard sensors, high-performance edge computing, and an auxiliary electric thruster used for precision maneuvering or navigating “doldrum” conditions.

• DSEI 2025: SEA, KraitSense, and the ASW gap – Calibre Defence 
• Thales delivers MMCM USV to French Navy – Calibre Defence

In mid-2025, Liquid Robotics expanded the platform’s capabilities with the launch of the SV5 variant. Measuring over five meters in length, the SV5 offers significantly increased solar collection and power storage compared to its predecessors. This allows the platform to support more “power-hungry” defence payloads and operate more effectively in high-latitude environments where solar energy is limited. Because the vehicle lacks a traditional engine, it operates with a negligible acoustic and thermal signature, making it a difficult-to-detect asset for long-term surveillance. It has been used extensively for scientific purposes, including the collection of data on important marine species such as snow crabs, wild Atlantic salmon, cod, seals, and white sharks. 

But what does it do for defence? 

The primary military application for the Wave Glider—often referred to in defence contexts as the SHARC (Sensor Hosting Autonomous Remote Craft)—is Undersea Domain Awareness (UDA). By towing “thin-line” passive acoustic arrays, such as the KraitArray, the platform functions as a persistent, low-cost “tripwire” for ASW. These autonomous fleets can patrol vast littoral or chokepoint regions for months at a time, detecting subsurface threats and relaying targeting data to crewed assets, such as P-8 Poseidon aircraft or carrier strike groups.

• Oceanus12 USV achieves several firsts during REPMUS – Calibre Defence 
• Project CABOT, transforming ASW for the Royal Navy – Calibre Defence 

Whilst earlier engagement with the US Government has focused on R&D and prototype work, it seems that the contract with SEA will see some scaling of the SHARC platform as well as the KraitArray. 

Speaking to Calibre Defence in September, Darren Boyle, the Technical Director at SEA said, “We can’t build our way out of the ASW threat, and we face a recognised shortage of ASW operators.” The company sees KraitArray, combined with uncrewed vessels, as a way to complement that limited pool of expertise.

KraitSense is a miniaturised passive towed array sonar system, with the KraitArray sensor measuring 20 mm in diameter. It has a low drag profile, requiring approximately 10 kg of force to be towed through water, making it suitable for low-power boats and autonomous platforms. The system’s power consumption is low, operating at less than 10 W for a 64-channel configuration. KraitSense can also be deployed statically on a buoy or seabed and can be cross-decked while in service. 

Calibre comment: USVs with towed arrays, a growing trend

SEA and Liquid Robotics aren’t alone in this field. The maritime mine-counter measures (MMCM) from Thales, which is being co-developed by the UK and France, is an uncrewed surface vessel that employs the Thales TSAM towed sonar. And the British company Zero USV claimed a world first in September 2025 when its Oceanus12 USV autonomously deployed and recovered an acoustic towed array during REPMUS. This approach allows a navy to rapidly increase the number of sensors that it has for the ASW mission, which is generally resource intensive. The UK is trying to achieve this mass and persistence through its Project CABOT, which aims to deploy a large fleet of autonomous vessels in the maritime domain awareness role to help guard against Russian incursions in British waters. However, most are at pains to emphasise that these uncrewed assets do not, and cannot, replace larger expensive crewed platforms like the Type 26 ASW frigate. 

By Sam Cranny-Evans, published on January 8th, 2026. Credit for the lead image is SEA. It shows the Wave Glider with a KraitArray on the deck of a ship.