In focus: the versatile new workboats being built for the Royal Navy

In September 2017 it was announced that Atlas Elektronik UK (AEUK) had won a £48M contract to supply up to 38 modular, multipurpose workboats for the RN. In this article, we look at these small craft in detail and how they will deliver enhanced capabilities to the fleet.

Project Vahana is the RN’s plan to replace a miscellaneous collection of launches and workboats (under 20m in length) with new vessels. These boats will be known as the ‘SEA class’ and there will be several variants based on a common hull. The first, and by far the largest vessel, survey launch HMS Magpie, has already been delivered and commissioned. More deliveries are due this year with the last boat due in service by 2021. AEUK is also responsible for the provision of initial in-service support for the vessels from 2018-24, which includes spare parts, regular maintenance and training.

The majority of the SEA class construction is being done in the UK. The main manufacture and assembly is done at AEUK’s Winfrith facility in Dorset, with testing on the Bincleaves Range in Portland Harbour. The boats will all be powered by two Yanmar marine diesels (which range in output from 350hp to 1000hp) prepared by Barrus Ltd at their custom engine facility in Bicester. Mashfords Boatyard at Cremyll, near Plymouth, has also been subcontracted for some assembly work. BMT Defence Services are supporting the project by providing safety, environmental management analysis and technical documentation.

The workboat fleet


The baseline workboat design can be customised with removable modules which can be transported by road, allowing the craft to be adapted for different tasks. All variants are capable of operating in up to Sea State 4 and sustain a maximum of 25 knots. Enduring high speeds in small craft, in all but the calmest seas, is very tiring for crew and passengers so KPM Marine DS100 shock-mitigation seats are fitted throughout. Living space is confined but all of the boats have at least 2 or 4 berths, a toilet, shower and galley in the forward area under the wheelhouse. Provision of basic accommodation for personnel extends the boats potential operating area and time in use.

Most of the workboats will be based in and around the three RN naval bases. Three of the 11m boats will be allocated to Hydrographic survey ships and replace the existing 9m Survey Motor Boats on board HMS Echo and Enterprise and Arctic patrol ship, HMS Protector. All three 13m boats will be allocated to HMS Prince of Wales as Passenger Transfer Boats (PTB). Able to embark 36 passengers, the boats are lowered to the water vertically through the sponsons that overhang from each side of the carrier. PTBs are intended to move personnel to and from shore, especially where port facilities are too small to allow the carrier alongside but are not intended for use in the amphibious assault role. (It should be noted that HMS Queen Elizabeth can embark three of the four ALN-139 passenger transfer boats of a quite different design supplied by Alnmaritec in 2017).

It is also likely the workboats will be embarked on Royal Fleet Auxiliary ships and Ocean survey vessel HMS Scott. Seven of the boats will be fitted with a diver support module and will be used to train and support personnel of three Fleet Diving Groups. Eight of the boats will be based on the river Dart for use by officers under training at Brittania Royal Navy College. They will replace the fleet of ageing picket boats used by the college for basic navigation, seamanship and leadership training. The officer training module will have additional bunks, workstations and teaching space.

HMS Magpie will be complemented by three 15m boats fitted with a survey module for other inshore and harbour hydrography work. The balance of boats will be used for general logistic and transport tasks and are fitted with a small davit for embarking stores. The Royal Marines will also receive some of the smaller boats to support amphibious training and operations.


Other than HMS Magpie, The hull form of the SEA class is derived from the same 11mm ARCIMS (Atlas Remote Capability Integrated Mission Suite) boats already in service with the RN being used to develop autonomous mine warfare. There are four size variants; 11m, 13m, 15m and 18m length. The boats are constructed from glass-reinforced plastic and are propelled by Yanmar diesels driving twin waterjets. All have common steering and control systems and components which will simplify operator training, logistics and maintenance. The boats could be further adapted in future as their control systems are compatible with the ATLAS autonomy engine designed by AEUK for unmanned surface vessels. AEUK is also developing compatible littoral anti-submarine technology to be embarked in small boats, in addition to their proven minehunting and hydrography packages.

The RN has already begun training coxswains who will drive the new SEA class with courses run at HMS Raliegh. Army Combat Support Boats have been used until the new boats are available – they possess similar twin engines with steerable pump jets which allow the boats to traverse sideways. This greater manoeuvrability assists in coming alongside jetties where space may be limited. Waterjet powered workboats handle quite differently to Pacific 24 RIBs which most RN seamen are currently trained on.

  • HMS Magpie has a high buoyancy bow form, which allows her to operate in quite heavy sea states without slamming occurring on her bridge deck. Seen here on trials off Ireland (Photo: Safehaven Marine)

  • HMS Magpie’s powerful engines kick up a fine twin ‘rooster tail’ during trials. (Photo: Safehaven Marine)

  • Magpie is propelled by a two 900hp Yanmar 6AYM 20.3 litre diesel engines (top left) driving twin Hamilton HM521 waterjets. (bottom left) Her catamaran hull and twin waterjet design can be seen as she is transported by road from the construction facility.

  • HMS Gleaner

    Inshore survey vessel HMS Gleaner (15 meters long) served in the RN from 1983-2018 before being replaced by HMS Magpie. Her last major role was surveying Rosyth Dockyard, the Firth of Forth and Portsmouth harbour to ensure safe navigation for HMS Queen Elizabeth.

  • Survey Motor Boat

    Being replaced – 9m Survey Motor Boats including ‘James Caird IV’ (HMS Protector) and ‘Spitfire’ (HMS Enterprise).

  • Being replaced – Picket boats used by officers cadets on the River Dart at BRNC (Photo: Jason Ballard) and Diving Support Boats (Photo: Photo CreatureStream )

HMS Magpie

Under a subcontract with AEUK, Safehaven Marine based in Cobh, Ireland, experts in high-performance small craft, constructed HMS Magpie to their proven Wildcat 60 design. Following initial Sea Trials, the vessel was delivered to Portland for additional equipment fit and acceptance trials. She arrived in Devonport for the first time on the 22nd June and was formally commissioned into the RN on 28th June.

HMS Magpie is a major upgrade on HMS Gleaner, the vessel she replaced, with a big increase in displacement from 22 tonnes to 37 tonnes. Magpie is also capable of double the speed (23 knots) and transits in rough conditions, she is fitted with a very sophisticated navigation and communications package supplied by AMBEX. Her raised bridge deck gives the helmsman and navigator a good view, enabling safe close-quarters manoeuvring.

There is accommodation for her 9 crew to sleep on board in two cabins and is fully air-conditioned throughout. Her main cabin is fitted with a small dining area which opens onto the main working module, incorporating computer racking for electronic equipment and workstations for 6 personnel. A Palfinger PK6500 crane is fitted for lifting cargo and survey equipment on to her aft deck area, which also has a small winch for deploying hydrographic sonar equipment.

Project Vahana does not include the supply of boats to replace HMS Sabre and Scimitar of the RN Gibraltar Squadron. The MoD plans to replace them in 2019 with larger, faster and more heavily armed vessels capable of 35 knots, day and night and operations in sea state 6-7. Although the MoD is looking for at least three bids, Safehaven Marine who built HMS Magpie may be in pole position, potentially utilising a derivative of their excellent Barracuda design. The Irish Navy is planning to build a large €200M Multi-Role Vessel (Possibly similar to military sealift ship HMNZS Canterbury). Giving further work to Safehaven in Ireland may encourage the Dublin government to place the MRV order in the UK.Sea Class Workboat Variants

It is still early days but the SEA Class workboat project appears to be a very cost-effective procurement that will give the RN a standardised, but very flexible fleet of small craft to serve in a wide range of roles.