Australia Turns Solar Powered Bluebottle Drones Into Submarine Detection Platforms for Navy.

Australia is expanding the anti-submarine warfare capabilities of its Bluebottle unmanned surface vessels by integrating new acoustic sensors designed to detect underwater threats across its maritime approaches. The development allows the Royal Australian Navy to deploy autonomous platforms for persistent underwater surveillance, reducing its dependence on crewed warships and maritime patrol aircraft to monitor large areas of the Indian and Pacific Oceans.

An Australian-built Ocius Bluebottle unmanned surface vessel participates in the Royal Australian Navy's Autonomous Warrior 2023 exercise at Jervis Bay, Australia, as the platform evolves toward submarine detection missions using towed-array sonar systems. (Picture source: Australian Department of Defence)

Developed by Australian company Ocius Technology, the Bluebottle is a long-endurance unmanned surface vessel (USV) powered by renewable energy. Its ability to remain at sea for extended periods makes it particularly suited to monitoring Australia's northern approaches, where submarine movements and maritime traffic must be tracked across thousands of kilometres. The integration of towed-array sonars extends its existing surface surveillance role into underwater detection.

On October 19, 2026, the Australian Department of Defence announced the development and integration of new payloads for the Bluebottle, alongside the Ghost Shark and Speartooth autonomous underwater vehicles. During a press conference in Sydney, Defence Industry Minister Pat Conroy confirmed that the Bluebottle would receive a thin-line towed-array sonar capable of detecting submarines. The announcement formed part of preparations for Maritime Big Play Pacific, an AUKUS Pillar II exercise involving Australia, the United States and the United Kingdom.

The Bluebottle's development also builds on several years of experimentation within the Royal Australian Navy. The platform featured in Autonomous Warrior 2023, a naval experimentation activity conducted between October 15 and November 3, 2023, primarily around Jervis Bay. The exercise focused on undersea warfare objectives and the integration of robotic and autonomous systems into Australian maritime operations. Developed with support from Australia's Defence Innovation Hub, the Bluebottle was originally intended to provide persistent surveillance of maritime approaches, commercial shipping routes and marine resources. Its latest acoustic payloads extend this mission toward the detection of potential underwater threats.

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Bluebottle Combines Renewable Energy With Advanced Acoustic Sensors

The Bluebottle uses solar panels, wind propulsion and wave energy to sustain operations without conventional fuel supplies. This configuration allows the vessel to remain deployed for weeks or potentially months, depending on environmental conditions and mission requirements. Its low-speed operating profile also makes it suitable for acoustic surveillance, where limiting propulsion noise can improve underwater signal collection.

The new capability involves two acoustic systems selected for different Australian maritime surveillance requirements. Under the Royal Australian Navy's SEA 1200 program, Ocius has contracted American company ThayerMahan to supply 40 Outpost acoustic intelligence payloads equipped with TransparenSea processing software. These systems are intended for the Navy's newly ordered Bluebottle fleet, providing an additional means of monitoring underwater activity across Australia's maritime approaches.

Separately, Ocius has selected the Australian-manufactured BlueSentry thin-line towed-array sonar developed by Thales Australia for Bluebottle vessels supporting Australian Maritime Border Command operations. The system uses fibre-optic acoustic sensing technology and can be deployed behind an unmanned vessel to collect underwater sound signatures. Its array has a diameter of 26 millimetres and operates at towing speeds between 0.5 and 4 knots, according to Thales' technical specifications.

Unlike an active sonar that emits acoustic pulses, a passive towed array listens for sounds generated by underwater contacts, including machinery noise and propulsion signatures associated with submarines. Its effectiveness depends on acoustic conditions, target characteristics and signal processing. Detecting a contact does not necessarily provide a confirmed identification or continuous track.

Australia Expands Its Autonomous Underwater Surveillance Network

The integration of these sensors accompanies a wider expansion of Australia's autonomous naval fleet. In March 2026, the Australian government announced an investment of A$176 million to acquire 40 additional Bluebottle vessels for the Royal Australian Navy. Another 15 Bluebottles are already operated by Australia's maritime border authorities, primarily supporting surveillance and border protection missions in northern waters.

For naval commanders, the tactical advantage lies in distributing acoustic sensors across maritime approaches without maintaining continuous deployments of crewed platforms. Multiple Bluebottles could occupy surveillance positions, monitor underwater activity and transmit information to command centres for analysis. Potential submarine contacts could then be investigated by maritime patrol aircraft, helicopters or surface combatants. Such a network would complement existing anti-submarine warfare capabilities, although secure communications, acoustic classification and coordination between platforms remain operational constraints.

Australia is also expanding the industrial infrastructure needed to sustain these deployments. Ocius inaugurated a new production and operations facility in Sydney on October 16, 2026, incorporating a continuous monitoring centre for deployed vessels. The company has also established a maintenance presence in New Zealand, while Australia is preparing to provide Bluebottles to Fiji for maritime security missions against illegal fishing and transnational crime.

The Bluebottle program reflects Australia's broader effort to establish a naval force combining conventional warships, submarines and autonomous platforms. Growing strategic competition across the Indo-Pacific has increased the importance of monitoring maritime approaches, protecting commercial shipping routes and maintaining awareness of underwater activity near critical sea lanes. By extending acoustic surveillance through relatively small autonomous vessels, Canberra is seeking to complicate covert submarine operations while strengthening maritime cooperation with regional partners and AUKUS allies. The development also illustrates how distributed underwater surveillance networks could contribute to maritime deterrence without requiring a proportional expansion of crewed naval forces.

Written By Erwan Halna du Fretay - Defense Analyst, Army Recognition Group
Erwan Halna du Fretay holds a Master’s degree in International Relations and has experience studying conflicts and global arms transfers. His research interests include security and strategic studies, particularly the dynamics of the defense industry, the evolution of military technologies, and the strategic transformation of armed forces.

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