A joint US-UK project focused on countering uncrewed underwater vehicles has been initiated, reflecting the deepening concern among Western militaries about the submarine threat emerging in contested waters worldwide.
The UK and US are looking for technology to counter the threat posed by underwater drones to ships, harbours and other critical maritime infrastructure, according to the Robotic Exclusion and Engagement Framework, known as REEF. The deadline to submit ideas for the challenge is April 3, with solutions assessed by both American and British defence innovation teams.
The timing reflects urgent operational realities. Iran is believed to be behind at least two explosive-laden sea drone attacks on oil tankers in the Gulf since the US and Israel first attacked Iran on February 28, with the first attack occurring on March 1 about 44 nautical miles off Oman and the second on March 5 hitting a Bahamas-flagged crude oil tanker near the Iraqi port of Khor Al Zubair. Separately, Turkish officials indicated an unmanned underwater vehicle was responsible for an attack targeting a tanker's engine room in the Black Sea.
Iran is known to possess and use autonomous underwater vehicles in conflicts dating back two years, and specifically shipped torpedo-like drones and one-way attack underwater drones to Houthi rebels in Yemen in 2024. Meanwhile, Ukraine has launched devastating attacks on Russian ships using much cheaper drones, demonstrating the military potential of these systems across different theatres.
The challenge facing naval planners is structural. Current solutions are fragmented, expensive, and limited in number, the solicitation notes. Adversaries and non-state actors are increasingly utilising autonomous underwater vehicles, including unmanned underwater vehicles, remotely operated vehicles, and semi-submersibles, posing a growing threat to critical infrastructure, waterways, ports, harbours, and expeditionary forces.
What REEF seeks is comprehensive. The commercial solutions opening seeks a suite of systems approach to address the REEF challenge, leveraging commercial off-the-shelf sensors, edge processing, sensor fusion, software, and interdiction methods to create a flexible, stand-alone system adaptable to various environments and integrable with existing systems. The framework requires solutions across four areas: detection and tracking capabilities, defeat mechanisms, secure communications, and command and control integration.
REEF will emphasise decoys to protect waterways and critical infrastructure, with capabilities to confuse adversarial underwater craft of high interest, including low-cost attritable systems or more technologically advanced systems that use signals to act as a decoy.
For the UK, the project is being delivered through Cyber and Specialist Operations Command's Innovation team, the jHub, meaning British companies can apply with solutions assessed for potential UK defence use. The estimated value of the requirement is valued at 1 million pounds.
For Australian defence strategists watching the Indo-Pacific, the significance runs deeper than procurement timelines. The emergence of relatively low-cost autonomous underwater systems that can evade detection and inflict damage on high-value assets challenges traditional naval doctrine built around crewed surface combatants. The fact that Western navies must now compete with commercial suppliers to develop basic defences against this threat suggests the technological gap is real and widening. REEF should require little training to operate and use artificial intelligence to provide users with suggestions, compatible with existing US command-and-control systems and common operating pictures.
Successful submissions will likely inform not only American and British capabilities but ripple through allied naval planning globally. For the Indo-Pacific's critical shipping corridors and energy lifelines, the race to master underwater drone defence has become as strategically important as traditional air and surface superiority.