RFA Lyme Bay is to be equipped with autonomous and remotely-controlled mine hunting systems in Gibraltar. This will prepare the ship to support mine clearance operations in the Gulf region, if called upon.

RFA Lyme Bay was reactivated at short notice in early March after a period of inactivity alongside in Gibraltar, following a maintenance period completed in December. She was deployed to the Eastern Mediterranean and sailed from Gibraltar on 15th March. In recent weeks, the ship has been operating off Cyprus, deployed as a precaution to support non-combatant evacuation operations if required. Additional personnel, including medical teams and Royal Marines, were flown out to Gibraltar to embark as part of preparations. 

Lyme Bay will return to Gibraltar to be fitted with containerised and modular mine countermeasure systems designed to detect, classify and neutralise mines using a combination of Uncrewed Surface Vessels and Uncrewed Underwater Vehicles. While alongside, Lyme Bay will also undergo inspections to ensure she is ready for sustained operations. 

It is unclear exactly what systems will be embarked on Lyme Bay, but so far, in the transition to autonomy, the RN has taken delivery of most of MMCM Block 1. This consists of 3 mission systems – comprising 2 USVs, sonars, ROVs and Portable Control Centres. In addition, the new MHC toolkit includes minesweeping USVs that tow coils designed to mimic the acoustic or magnetic signature of a ship and detonate seabed mines. The RN also has a suite of smaller ROVs and UUVs in use for mine hunting and disposal. 

The concept builds on several years of experimentation by the RN and its partners. Bay-class ships have previously deployed to the Gulf in a similar role, initially supporting crewed minehunters and more recently also embarking UK and US autonomous systems. In 2023, a Portable Operations Centre (POC) was embarked in RFA Cardigan Bay in Bahrain and the USV, RNMB Harrier operating a mineweeping system was tested on operations from the ship. The smaller REMUS series of UUVs for mine hunting purposes was also deployed in the Gulf for many years. The presence of the Bay-class vessels in the region ended when RFA Cardigan Bay left Bahrain on March 2024 and was not replaced.

Containerised Portable Operations Centre (POC) embarked in RFA Cardigan Bay in Bahrain during 2023.

The new systems being installed on Lyme Bay are designed for rapid integration of different sensors and vehicles depending on the mission. This approach is central to the RN’s future ‘hybrid fleet’ and mine warfare model, replacing crewed vessels with a distributed system of autonomous platforms controlled from a variety of host ships or shore facilities.

The reactivation of Lyme Bay and her conversion into an MCM mothership highlight both the opportunities and constraints facing the RN. Autonomous systems offer a route to more efficient and survivable mine warfare and their rapid deployment aboard an RFA platform reflects the flexibility of the new system. However, this is still a very immature capability and still thousands of miles from where it might usefully be employed.

The dedicated mine-hunting Mothership, HMS Stirling Castle, continues in her primary role supporting the trials and development of autonomous mine hunting capabilities in UK waters. Despite being crewed by the RN, she is completely unarmed and even less suitable for deployment into higher threat areas than Lyme Bay.

US Navy personnel embarked aboard RFA Lyme Bay checks on their Remus Mk-18 Mod 1 UUVs as part of a UK – US Mine Countermeasures Exercise, November 2017 (Photo: US Navy).

This measure should be seen as a sensible preparation that would allow the RN to offer the government another option, but immediate deployment to the Gulf region is highly unlikely without a change in circumstances. Even the mighty US Navy is not taking the risk of sending high end warships through the Startif of Hormuz, never mind auxiliaries. Any attempt at mine clearance in the Gulf, whether utilising MCMVs or USVs, would first require almost complete degradation of Iranian forces, close armed overwatch or more likely, a ceasefire.