RFA Stirling Castle

RFA Stirling Castle is a ship of the Royal Fleet Auxiliary operated by the Ministry of Defence. Acquired in 2023, the ship entered drydock at HMNB Devonport for modification into a trials platform for autonomous minehunting systems that are to operate from a larger mother ship. The ship was formerly named MV Island Crown, and used as an offshore supply vessel operated by Island Offshore. The vessel was sold to the Ministry of Defence in January 2023 for £40 million.

Stirling Castle is one of two new commercial vessels acquired for the Royal Fleet Auxiliary in 2023, the other being RFA Proteus, a multi-role ocean surveillance ship to protect seabed infrastructure and communications. Up to three additional ships performing the role of mine countermeasures command and support vessel are also planned for acquisition. These will either be converted former commercial vessels, similar to RFA Stirling Castle, or new purpose-built ships, as reportedly preferred by the navy. These vessels will fill a gap left as a result of the retirement of the Royal Navy's Sandown-class minehunters, all of which are scheduled to leave service by 2025.

MV Island Crown
The ship operated as the offshore support vessel MV Island Crown for Island Offshore from March 2013 until July 2017 under the flag of the Bahamas and registered in Nassau. From July 2017 until March 2023 it sailed under the flag of Norway, registered in Ålesund. Designed by Rolls-Royce and built by Vard Brăila, Romania the primary capabilities of the Island Crown were to support subsea and offshore oil, gas, and renewable energy operations.

Projects for which the Island Crown was deployed includes supporting and accommodating workers on the construction of the East Anglia Array offshore wind farm near the United Kingdom.

RFA Stirling Castle
Owing to the UK's government's growing concern about protecting subsea infrastructure, and the 2022 Russian invasion of Ukraine, the Island Crown was purchased by the UK's Ministry of Defence in February 2023 to be converted into a platform for mine countermeasure operations, to be operated by the Royal Fleet Auxiliary and have pennant number M01. Initial conversion for naval service was conducted at HMNB Devonport in Plymouth, UK. The primary focus of the Stirling Castle is as a trials platform to act as an offshore forward operating base, deploying Mine Countermeasures Maritime Autonomous Systems (MCM MAS), and drones to protect offshore subsea infrastructure. It will also be used as a platform for training RFA personnel on MCM MAS operations. For the employment of unmanned systems, the ship incorporates a crane with a safe working load of 10 tonnes at a 34m radius and 5 tonnes at a 40m radius. The ship's conversion was said to have been completed in May 2023 and she began sea trials prior to assuming her new role.

In July 2023, the ship conducted its first trials with three of the Navy's autonomous vessels: Royal Navy motor boats Apollo, Hydra and Hazard. In December it was reported that the ship has been engaged in few activities since those initial trials. Her formal naming ceremony was delayed until Spring 2024 with reports suggesting that she might have to undergo docking in order to correct certain defects. However, from January to March 2024 Stirling Castle was reported to have undertaken additional operational sea training in preparation for work with the Mine and Threat Exploitation Group at the Clyde naval base. In April 2024, in a ceremony attended by Prince Edward, Duke of Edinburgh, the ship formally entered service with the RFA.