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In focus: CETUS the Royal Navy’s next
XLUUV | Navy Lookout
NavyLookout
9–11 Minuten
Following trials with the experimental MANTA extra large uncrewed
underwater vehicle (XLUUV), CETUS the RN’s next advanced
technology demonstrator has entered the manufacturing phase. Here
we provide some more details of the project.
Background
MANTA (S2O1) built by MSubs of Plymouth and delivered in March
2020 is the first XLUUV technology demonstrator utilised by the RN
although, her builders retain ownership. In order to gain experience with
this novel type of vehicle, a 3-phase approach was adopted. Phase 1
covered delivery, basic seaworthiness and autonomy tests. Phase 2
began mission testing of gradually increasing complexity. Phase 3 is
underway now the submarine is more closely integrated with the navy
MARCAP (Maritime Capability) team and conducting trials that relate
more directly to the operational environment and de-risk future
technologies. During October 2023, MANTA was used to run a ‘D-Day
demonstration’ conducting reconnaissance and surveys off a Cornish
beach, simulating the kind of pre-assault tasks conducted by special
forces and crewed mini-submarines in 1944. The intelligence gathered
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was sent ashore via satellite to a containerised Portable Operations
Centre (POC) which could potentially be sited anywhere in the world or
embarked on a ship at sea.
S201 will be returned to MSubs for refit and possible sale to another
navy. In order to de-risk some of the technologies that will go into
CETUS, a second vessel S202 has been constructed by MSubs. The
company is also creating new jobs and investing in a new facility at South
Yard in Devonport, much closer to the waterfront than their existing
factory in Estover on the outskirts of Plymouth.
The competition for an 8-12m XLUUV was started in early 20221 and
MSubs were awarded the £21.5 million contract for CETUS in
November last year. The craft is now in the manufacturing phase before
she begins sea trials in November 2024. MANTA was based on an
existing and proven submersible design but CETUS is being designed
and built from scratch and will be the first XLUUV owned and operated
by the RN under the auspices of the Submarine Delivery Agency’s
Autonomy Unit (SDA-AU). Overall this project will span 6 years and
following delivery, the Navy intends to employ her on trials and
experimentation until at least 2027.
The RN’s project SPEARHEAD has multiple strands across the board to
improve its anti-submarine warfare capability. Concept Studies for
SSN(R), (now SSN-AUKUS) found that there would be great value in
augmenting crewed submarines with autonomous systems. The RN
needs to increase its underwater mass and a large number of
Autonomous Underwater Vehicles will be needed by 2040. The
autonomy unit of SPEARHEAD includes CETUS (Annex H) and
CHARYBDIS (Annex F) – the development of a system of systems for
anti-submarine warfare. (We will look at CHARYBDIS in more detail in a
future article). The lessons derived from MANTA and CETUS will
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contribute to the RN’s plans for the Integrated Review due in 2025 and
the RN’s Develop Directorate is also considering if there are systems
that show sufficient promise to be adopted quickly for frontline use.
• Arrangement
• Payload
• Extend
• AUGV
• Model
• X-Tail
• Manta
• CETUS is a modular XLUUV featuring two pressure vessels separated
by a central (flooding) payload bay.
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The payload bay is designed to accommodate all kinds of equipment. In
the mock-up here, an ROV is in the centre of the bay with its umbilical
line on the reel forward. The reel aft is for a towed array sonar (Photo:
Navy Lookout).
• CETUS with additional payload module insert.
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The Bayonet 250 is an Autonomous Underwater Ground Vehicle.
AUGVs were primarily designed for survey operations in the surf zone
but the RN envisages these and could be lowered onto the seabed from
an XLUUV payload bay and carry out missions including
reconnaissance or minelaying (Images: Greensea IQ).
• 1/10th scale CETUS model on display under moody lighting on the
Royal Navy stand at DSEI 2023. Initial images showed the two
communications and sensor masts folding forward but recent imagery
suggests they will retract vertically like a traditional periscope. Video Ray
Mission Specialist Defender ROV model below (Photo: Navy Lookout).
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Every self-respecting submersible has an X-tail these days (Photo: Navy
Lookout).
• Manta with towed array.
Demonstrator
CETUS will be the largest and most complex uncrewed submersible
operated by any European navy. It is officially described as “A
representative large-scale AUV demonstrator to build trust in long
endurance autonomous operations and be an adaptable testbed for
mission payloads”. The 17-tonne submarine will be 12 metres long and
2.1 metres in diameter. Although an FEU can be loaded into a Type 26
Frigate Mission Bay, CETUS is too heavy for the ship’s mission bay
handling system, precluding it from being offloaded at sea. It would be
less of a problem for handling by ‘motherships’ with powerful cranes
(such as RFA Proteus for example).
Notably, the vessel will be able to dive deeper than any vessel in the
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current submarine fleet and endurance is described vaguely as ‘several
days’. It is a modular design with an optional payload section that can be
added to double the capacity of the vessel while endurance can be
increased by installing additional batteries. For the sake of simplicity, cost
and weight it does not feature diesel generators for re-charging but the
power density of batteries continues to improve. The potential fire
hazards posed by high-powered batteries, when embarked on ships, will
be a fire-fighting and damage control mitigation challenge.
Like most XLUUV designs in development worldwide, the standard size
CETUS version will fit inside a 40-foot container (FEU) which is a
manageable standard size for road transportation and shipping. The
standard Main Payload Space (MPS) in the centre module is 2m x 2m x
2m and there are small Secondary payload spaces in the upper fore-end
and lower aft end, likely to be occupied by sensors.
The RN is interested in proposals from industry for potential payloads
that can be rapidly switched in and out for trial purposes and eventual
mission flexibility. The MPS has doors top and bottom that allow items to
be loaded in from above and to exit from the underside of the craft when
deployed underwater. Examples of potential payloads on display at
DSEI included an ROV deployed on an umbilical from the mission bay
and an Autonomous Underwater Ground Vehicle (AUGV) that can be
lowered to transit across the seabed.
Beyond CETUS
BAE Systems bid unsuccessfully for CETUS but continues to develop
HERNE, their self-funded XLUUV solution. A first public demonstration
of HERNE at sea will be conducted in September 2024 from Portland,
configured initially for ISR missions. Herne is not specifically aimed at the
RN and is intended to have worldwide export potential with the protection
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of underwater Critical National Infrastructure (CUI) capabilities as a key
selling point. The vessel is approximately the same size as CETUS and
has a similar modular design philosophy but its layout is different with its
payload bay placed forward and the propulsion module aft with a small
shrouded propulsor.
• Herne Video
• ISR
• Model
• Side door
• Bottom door
• Solus XR-2
• BAE Systems Herne XLUAV concept
• Sensor masts raised during ISR operations (CGI: BAE Systems).
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Basic model shows the positioning of the propulsion module (green),
batteries (orange) sensor masts (blue) trim and depth control (purple).
• The forward bay has side doors for the main payloads.
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There are doors top and bottom of the payload bay for small UUVs or
weapons.
• The Canadian Cellula Solus XR-2 is powered by hydrogen fuel cells
providing a submerged range of over 5,000 km at 3 knots. It was
designed with under-ice operations in the Arctic in mind (CGI: Cellula).
While developing HERNE, BAES has partnered with a Canadian
company Cellula Robotics, which considerable underwater autonomy
expertise, and their Solus-XR XLAUV has already begun sea trials.
HERNE’s command chain design is also underpinned by BAES’ seven
years of experience with autonomous surface craft and their new
software is being tested on one of Cellula’s vehicles. Every component of
HERNE has been designed to have a low signature and utilises proven
autonomous navigation and collision avoidance technology. The
software has been designed for rapid reconfiguration depending on the
mission, having robust and secure communication with host platforms
either at sea or ashore.
Assuming the RN plans to acquire a fleet of operational XLUUVs
following on from CETUS, BAE Systems would be well placed to build
the next generation. It is possible there could be a collaboration with
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MSubs, with BAES able to provide the high-end integration expertise
and manufacturing scale needed. In the meantime, CETUS is an
important step on the road to adding mass and more diversity of
capabilities for the Royal Navy in the increasingly contested underwater
battlespace.
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