Sea-class workboat. The Sea-class workboat has been procured for Britain's Royal Navy to undertake a number of roles, including: logistics and transport tasks, inshore and harbour survey work, diver training and support, officer training and providing passenger transfer modules for the aircraft carrier . An autonomous minehunting variant of the class has also been procured.

A procurement contract for £48M was awarded to Atlas Elektronik UK (AEUK) in September 2017 for the delivery of up to 38 vessels under the program. Thirty-five vessels were ultimately built, with deliveries beginning in 2018 and completing in 2024. All vessels, with the exception of  (the largest boat in the series), are non-commissioned assets within the Royal Navy.

Vessel types and roles

The Sea-class workboat incorporates hulls that are interchangeable allowing them to adapted for different tasks. As initially acquired, the class includes several variants:

 10 x 11 m standard workboats for transport and logistics tasks; 
 3 x 11 m small survey modules (including units assigned to the ocean survey ship HMS Scott and the ice patrol ship HMS Protector);
 3 x 13.8 m passenger transfer modules (assigned to HMS Prince of Wales); 
 18 x 15 m workboats for officer training, diver training/support and survey/hydrography duties; and, 
 1 x 18 m inshore survey unit (HMS Magpie).

Eight 15-metre officer training vessels are assigned to the Britannia Royal Naval College, while the six 15-metre diver training and support vessels are assigned to HMNB Portsmouth (three units), HMNB Devonport, HMNB Clyde and to the Royal Navy's Gibraltar Squadron (one unit each). The final four 15-metre vessels are configured for survey/hydrographic work, with two of the vessels (Merlin and Fantome) being based with the Fleet Hydrography and Meteorology Unit at HMNB Devonport.

The vessels have been constructed to be fully compatible with AEUK’s autonomy engine enabling an unmanned capability to be integrated as a future need arises.

Autonomous minehunter

A specifically-focused autonomous minehunting vessel, also produced by Atlas Elektronik, is a derivative of the class (being identified by the navy as the Arcims-class). Five 11-metre variants of the type (RNMBs Hussar, Hazard, Halcyon, Harrier and Hydra) were acquired by the Royal Navy and assigned to the Mine Threat and Exploitation Group at HMNB Clyde. The vessels have been procured under the Mine Hydrographic Capability (MHC) programme and are fitted with acoustic, electronic, and magnetic payloads that can emit signals through a towed craft to trigger mines into thinking that a target ship is passing by. The boats can operate crewed, be remotely controlled or be pre-programmed to conduct missions autonomously. The 11 m boats can be transported on either the RAF's A400M or C-17 transport aircraft. 

An additional 15-metre minehunting variant (RNMB Hebe) was also procured and similarly assigned to the Clyde naval base. The greater size of Hebe permits her to accommodate a Portable Operations Centre Afloat that allows her to control her sister vessels while also coordinating autonomous operations.

In 2023, RNMB Harrier was tasked to undertake trials with the Royal Navy's 9th Mine Counter-Measures Squadron based at  in Bahrain. It is planned that autonomous minehunters, operating from command "mother ships", will incrementally supersede crewed minehunters operated by the Royal Navy.

See also
 
 
 Patrol Craft Fast - the "Swift Boats"

References

Auxiliary ships of the Royal Navy