MOMENTUM ROV
UNDERWATER PROPULSION
JULY 2026
UNDERWATER
R·O·B·O·T·I·C·S
20
Connecting What’s Needed with What’s Next™
Momentum™ Electric Work Class ROV
Electric power. Total control. Built for extreme subsea demands.
Connect with what’s next at Oceaneering.com/electric-rov
Copyright ©2026 Oceaneering International, Inc. All rights reserved.
NEWS
THRUSTERS
16
AUVS
44
58
ROV
Editor: John Howes
John@ut-2.com
+44 7859905550
Advertising:
Zinat Hassan
UT3subsea@gmail.com
Tel: +44 (0) 845 6522 483
Mobile: +44 (0) 781 1200 483
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MOMENTUM
ISSUE 20
JULY 2026
Cellula Robotics has signed a
Memorandum of Understanding
with Integer Technologies to
explore how Integer’s DIGIT
COMMAND software can layer
onto Cellula’s Nexus mission
control software through a back-
seat driver architecture.
For operators, the collaboration
addresses an important
challenge in long-range subsea
missions: maintaining
confidence, system awareness
and adaptive decision support
when vehicles are operating for
extended periods and
communications are constrained.
The intended architecture would
keep Nexus as the mission
control foundation for Cellula’s
AUV operations, while DIGIT
COMMAND would provide an
additional mission assurance and
decision-support layer.
CELLULA
ENVIREX
NEWS
OneSubsea, the joint venture established in 2023 by SLB, Aker
Solutions and Subsea7, has completed the acquisition of the
subsea business of Norwegian Envirex Group.
The transaction supports the continued development and
deployment of innovative subsea solutions including umbilical-
less and wireless systems, with the customers to benefit from a
broader and more advanced portfolio, supported by improved
global delivery consistency and lifecycle support.
Boskalis has announced the
successful first deployment of
remotely operated vehicles from
its new Remote Operations
Centre (ROC)in Aberdeen,
following an 18-month
development programme and an
investment of GB£40 million in
Boskalis Remote Operations
Centre in Aberdeen
ROVs and the ROC.
The ROC significantly expands
Boskalis’ remote operating
capabilities by enabling critical
subsea tasks to be supported
and controlled from shore.
The centre provides a central
hub for fleet operations, offers
additional on-demand
expertise to support offshore
crews and is designed to
enhance operational
efficiency, strengthen safety and
ensure consistent delivery across
projects
NEWS
NOVACAVI has supported the POLARIS project, an
innovative initiative led by ETH Zurich, one of the
world’s leading universities for science and
technology.
The POLARIS project involves the development of
an advanced autonomous underwater vehicle
designed for research applications in the fields of
climate monitoring and security.
One of the project’s main objectives is the accurate,
non-invasive measurement of ice thickness from
below. As the special vehicle moves beneath the
lake surface, it continuously collects data,
generating a high-resolution dataset capable of
mapping the spatial distribution of ice thickness.
This pioneering approach enables the collection of
highly precise data without the need to drill
through the ice, thereby avoiding surface
disturbance and significantly reducing risks for
personnel operating in extreme environmental
conditions.
NOVACAVI has contributed to the project through
the development of a neutrally buoyant cable, an
integral component that ensures system reliability,
enhances vehicle manoeuvrability
NOVACAVI SUPPORTS THE POLARIS PROJECT
Introducing KD300E,
our new electric thruster
made this!
Meet ,
the future unveiled
NEW!
Introducing ZEEROV (Zero Emission Electric Remotely Operated Vehicle) - the latest work-class ROV from
Kystdesign. Designed to push the boundaries of subsea exploration, ZEEROV delivers a new level of performance,
versatility, and sustainability. With its advanced electric propulsion system KD300E, ZEEROV is a zero-emission
vehicle that offers a more environmentally friendly alternative to traditional ROV´s.
kystdesign.no
Dynautics has won the Subsea and Underwater
Intervention award at the Seawork Innovations
Showcase for its Phantom 2 autonomous
underwater vehicle (AUV), recognising the
platform’s modular design and contribution to the
next generation of subsea operations.
Phantom 2 was showcased at Seawork in
Southampton, Europe’s largest commercial
marine and workboat event. The 3m modular AUV
is designed to be scaled around different payload
requirements, supporting flexible deployment
across offshore, subsea, oceanographic, defence
and security missions.
Dynautics used 3D models, digital twin creation
and simulation to customise the design of
Phantom 2 based around client needs, reducing
risk and time to market. Using its AUV Simulator
technology, Dynautics catalyses the development
process and optimises vehicle efficiency to ensure
reliable performance in complex marine
environments
Dynautics Seawork
Innovations Showcase
NORBIT has signed an agreement to acquire
100% of the shares in Water Linked, a Trondheim-
based provider of underwater navigation and
imaging technology. Founded in 2013, Water
Linked serves customers across global maritime,
defence and offshore energy markets. The
acquisition broadens and complements NORBIT’s
Oceans product offering and strengthens
NORBIT’s position as a supplier of tailored
technology to underwater vehicles.
Water Linked’s product portfolio includes Doppler
Velocity Logs (DVLs), 3D imaging sonars,
underwater modems and acoustic positioning
systems, enabling navigation, perception and
autonomy across subsea and surface applications,
including ROVs, AUVs and uncrewed surface
vessels operating in GPS-denied environments.
The products are used in applications such as
subsea inspection, offshore energy operations,
marine research, defence and underwater
infrastructure development.
NORBIT/Water Linked
NEWS
Phantom 2
THE EVOLUTION OF
MISSION SPECIALIST
OPERATIONS HAS ARRIVED.
Explore what’s possible at videoray.com
Launched last year, the recent
UDT exhibition marked the first
public showing of the Greyshark
in the UK. The Greyshark is a
high-speed, long-endurance AUV
characterised by a bio-inspired
hydrodynamic hull geometry and
a high-efficiency electric
propulsion architecture.
Jointly developed by Euroatlas
and EvoLogics, the platform is
engineered to support extended-
duration deployments,
cooperative multi-vehicle
operations, and high-resolution
sensor-driven situational
awareness.
The platform is available in two
primary configurations,
designated Foxtrot and Bravo,
each optimised for distinct
operational profiles.
The Foxtrot variant is the larger of
the two, measuring approximately
7.99m in length with a hull
diameter of 2m and a mass of
approximately 4.5t. It is powered
by a fuel cell-based electric
propulsion system, enabling long-
endurance missions. At a transit
speed of 10kts, it can achieve a
range of approximately 1100
nautical miles over a duration of
around five days.
When operating at a cruising
speed of 4kts, its endurance
extends significantly, allowing
traversal of up to 8,000 nautical
miles over approximately 16
weeks.
The integration of a high-precision
navigation system enables fully
submerged operation across its
entire operational range without
reliance on surface navigation
updates.
The Bravo variant is more compact,
with a length of approximately
6.5m, a hull diameter of 1.75m, and
a mass of roughly 3.5t.
GREYSHARK
NEWS
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Oceaneering Subsea Robotics Group
recently announced its latest electric work
class Remotely Operated Vehicle (ROV).
Named Momentum, the vehicle has been
designed for 30-day continuous subsea
operations, enabling extended support for
drilling, inspection, maintenance, and
repair (IMR), surveys, and construction
work scopes.
Momentum was developed using a
reliability-driven design approach that
reduces intervention frequency and
service time to enable resident
applications.
Featuring plug-and-play sensors,
advanced 360deg vision, automation,
strong thruster power and high payload
capacity, the Momentum can deliver what
is required for demanding work-class
operations. Offering backwards
compatibility with Millennium Plus ROV
infrastructure, Momentum supports quick
upgrades and scalable deployment.
DESIGN
At a time when subsea operations are
increasingly defined by depth, data fidelity
and autonomy, the latest generation of
heavy-duty remotely operated vehicles
(ROVs) reflects a clear architectural shift
away from purely pilot-driven systems
toward remotely-operated platforms
engineered for persistence.
The vehicle sits squarely in that transition
zone, combining high-power electric
propulsion, dense sensor integration and
cloud-linked operational intelligence in a
package designed for deepwater
intervention and inspection.
Pressure tolerant electronics and a water
jet and bolted frame modernise the ROVs
structure.
With an in-air weight of 4773kg and a
compact footprint of 3.3x1.6 x2.0m, the
frame balances deployability with the
ability to handle substantial subsea loads.
A standard operating depth of 3000m,
extendable to 4000m, places it well within
the envelope of deepwater oil and gas
fields as well as emerging offshore
Testing facilities
MOMENTUM
THE NEW ROV FROM OCEANEERING
ROV
11
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infrastructure zones. The through-frame lift capacity of
3500kg, coupled with an 800lb payload allowance,
signals a platform intended not just for observation but
for heavy intervention tasks, including tooling
deployment and component manipulation under high-
pressure conditions.
The sensing architecture is one of the defining features.
A distributed array of low-latency IP cameras provides
full 360-degree situational coverage, augmented by pan-
and-tilt units delivering high-definition imaging at 1920
by 1080 resolution with 30x optical zoom.
This visual system is not passive; it is tightly integrated
into a Visual Tracking and Positioning framework,
supported by forward-facing stereo cameras and
auxiliary viewpoints including tether and manipulator-
mounted feeds.In aggregate, the system produces a
spatially coherent visual field that can be reconstituted
into panoramic or bird’s-eye visualisations for the
operator, or ingested directly by onboard autonomy
modules.
Lighting is engineered to match the imaging stack, with
a baseline output of 120 000 lumens from six high-
efficiency units, and an optional configuration extending
to 160 000 lumens. This level of illumination is necessary
to counteract light attenuation and particulate scatter in
turbid water columns, particularly when high-resolution
imaging and machine vision are in play.
NAVIGATION
Positioning is derived from sensors as selected by the
operator to support the activity including Ultra-Short
Baseline acoustic systems, Doppler Velocity Logs, Inertial
Navigation Systems and vision-based tracking - an
ROV
ROV
13
increasingly critical capability for
operations that cannot rely on
seabed reference points. The
stereo forward facing cameras
provide midwater station-keeping
Automated control modes
extend across heading, depth,
altitude, and hover, with waypoint
navigation and cruise control
layered on top.
The inclusion of automated pitch
and roll stabilisation suggests a
control system designed to
compensate for external
disturbances.
Obstacle avoidance is handled
acoustically via forward-looking
sonar systems, including units
comparable to the Kongsberg
1171, providing real-time
situational awareness in low-
visibility environments where
optical systems degrade.
Redundancy is evident
throughout the navigation
stack, with backup
magnetometers and analog
depth sensors ensuring
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continued operation under
partial system failure.
DATA
The design of data architecture
is equally deliberate. A 10-
gigabit redundant fibre link
forms the primary
communication channel
between surface and vehicle,
with copper-based emergency
backup ensuring fail-safe
command and telemetry paths.
Internally, Intelligent Power and
Ethernet Modules (iPEMs)
provide plug-and-play power
and communications for sub-
assemblies, sensors, tooling,
and skids, streamlining
installation and replacement to
increase system availability.
A distributed 1-gigabit Ethernet
backbone connects
subsystems, supplemented by
legacy serial interfaces for
compatibility with existing
tooling and sensors.
Over 72 plug-and-play
connection points reflects its
modular design philosophy,
allowing rapid reconfiguration for
mission-specific payloads.
Pilot assistance is not limited to
ergonomic control interfaces.
The system incorporates a
robotics assistance layer that
aggregates visual feeds into
synthesised perspectives,
including stitched panoramas
and headset-based stereoscopic
views.
Collision avoidance is
implemented through both visual
and acoustic cues, while higher-
level functions such as object
identification, localisation, and
automatic event detection point
toward increasing use of machine
learning at the edge.
Notably, operational data is
streamed into cloud-based
systems for predictive
maintenance and troubleshooting,
closing the loop between field
performance and engineering
analysis.
PROPULSION
Propulsion is fully electric, driven
by dual 65kW transformer units
feeding a vectored thruster
configuration.
Four horizontal and four vertical
thrusters, each rated at 15kW,
provide balanced control authority
across all axes. The resulting
bollard pull—over 1000KgF in
both forward and lateral
directions, and nearly 1400KgfF
vertically—places the vehicle
firmly in the work-class category.
This is a system built to hold
position against currents while
simultaneously executing
precision manipulation.
Momentum
ROV
15
Momentum Launch and
Recovery System
Maintenance and availability
metrics reflect operational realities
offshore.
A 30-day no-touch maintenance
window reduces intervention
frequency, while system-level
redundancy allows isolation of
high-power faults without
cascading failures. Critical
component replacement in under
an hour suggests that
maintainability has been
engineered at the subsystem
level, not treated as an
afterthought.
Manipulation capability is
configurable, with dual
manipulators offering five or seven
functions under hydraulic or
hybrid control, and an option to
use fully electric manipulators that
are in development.
Tooling support is extensive.
Electrical distribution includes
more than fifteen 24v DC channels
and dual 120v AC supplies, while
hydraulic tooling delivers up to
50kW of power at 3000 psi with
multiple flow-controlled circuits.
The availability of an
electromechanical tool changer
system introduces the possibility
of subsea tool swapping without
vehicle recovery, a significant
efficiency gain for complex
intervention campaigns.
The tether management system
underscores the platform’s
flexibility. Available in both
hydraulic and electric
configurations, it
supports different
deployment
geometries, including
side-entry cages and
top-hat arrangements.
Tether lengths up to 1200
m in cage configuration
extend operational reach,
while integrated
cameras and high-
intensity lighting within
the TMS improve monitoring
during launch and recovery
phases—often the highest-
risk segments of an ROV
mission.
Launch and recovery
is compatible with
established
systems, including
A-frame
deployments and
heavy-lift winches,
ensuring
integration with existing vessel
infrastructure.
This backward compatibility is
critical in an industry where
capital equipment lifecycles span
decades.
Taken as a whole, the vehicle is
less a single machine and more a
platform architecture. Its defining
characteristic is not any
individual specification—depth
rating, thrust, or sensor count—
but the way these elements are
integrated into a cohesive
system designed for
operational efficiency.
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Selecting a thruster
for an underwater
vehicle begins with
understanding
vehicle's size, shape,
drag, mission
profile, and available
power. Because
underwater vehicles
vary widely in form
and function, the
best thruster is the
one that supports
the complete
vehicle design
rather than simply
meeting a thrust
value.
WHAT SORT OF ASPECTS SHOULD YOU CONSIDER IN
THRUSTERS
ELECTRIC TH
WANT A THRUSTERS FOR YOUR UNDERWATER
In a subsea glider effectively
powered by weight displacement,
thrusters are only used
occasionally, for example, to pass
through areas of different density.
These are small to present a
minimal footprint outside the
hydrodynamic body
Thruster design is a balance
between propeller diameter, blade
geometry, rotational speed,
available power, and the
hydrodynamic drag of the vehicle.
When considering a new
propulsion system, the first
question should not be which
thruster produces the most thrust,
but which thruster best matches the
vehicle's mission profile, power
architecture, operating depth,
hydrodynamic drag, duty cycle, and
long-term maintenance strategy.
A compact inspection ROV, a high-
speed survey vehicle or a work-
class platform all place different
demands on propulsion. Some
applications require maximum bollard
thrust, some precise station keeping
and others minimum power
consumption over long operating
periods.
The correct thruster is therefore not
selected by thrust rating alone, but by
how well it supports the complete
vehicle.
Rotational speed is a key design
consideration. For a given propeller,
increasing RPM can increase thrust but
may also reduce efficiency. As blade
speed increases, local pressure can drop
below the vapour pressure of water,
causing cavitation that reduces thrust
while increasing noise, vibration, and
potential blade erosion.
17
THE DECISION?
HRUSTERS 101
VEHICLE?
For this reason, larger and slower-turning propellers
are often preferred when the vehicle can
accommodate them. Moving a greater mass of
water more gradually is typically more efficient than
moving a smaller mass of water at very high velocity.
This is especially important for vehicles that require
endurance, low noise, or efficient transit. However,
larger propellers are not always practical for
compact ROVs, tight vehicle envelopes, or
applications where drag and packaging are limiting
factors.
Effective thruster design has many considerations.
The correct solution must balance vehicle size, drag,
available power, depth rating, efficiency, reliability,
and serviceability so the thruster performs as part of
the complete underwater vehicle system
"All things being equal, a streamlined vehicle
designed for long, efficient survey missions will have
very different propulsion requirements than a
vehicle designed for station keeping, intervention,
or precise low-speed manoeuvring," said Omar
Rafeh, President of Innerspace Thrusters.
"Physical space in smaller vehicles is at a premium
while larger work-class vehicles have more flexibility
for larger, slower-turning propellers. These
variations in vehicle size, shape and mission profile
are one of the reasons that there are so many
different thruster designs.
"Even before a new underwater vehicle design is
complete, the design team will usually have a
reasonable understanding of the vehicle
envelope, expected drag, operating speed,
available power, and manoeuvrability
requirements.
These factors help determine not only how much
thrust is required, but also how many thrusters
are needed and where they should be positioned
on the vehicle.
"For example, if a vehicle requires approximately
500 Ib of thrust, the next questions must
determine whether the thrust is best supplied by
DESIGNS
FET Electrical thruster
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an electric or hydraulic
propulsion system, and how
that choice affects efficiency,
control response, packaging,
maintenance, and integration
with the rest of the vehicle.
"Historically, smaller ROVs
were most often electric,
while larger work-class ROVs
relied heavily on hydraulic
propulsion.
That distinction is no longer as
clear as it once was. Large electric
work-class vehicles are now being
developed by major ROV
manufacturers, while many
vehicles still use hydraulics for
tooling, manipulators, or other
onboard systems.
"The final selection is therefore
not simply a matter of preference.
It is the result of balancing
GEARED VS DIRECT DRIVE
There are two common
approaches to electric thruster
design: direct drive and
geared.
In a direct-drive thruster, the
motor is mechanically coupled
to the propeller. When the
motor turns, the propeller turns
at the same speed. Direct-drive
thrusters tend to be more
responsive because torque is
transferred directly from the
motor to the propeller
"Innerspace generally favours
direct-drive systems where the
application allows because they
are mechanically simple,
responsive, and easier to
maintain," said Rafeh.
DIRECT DRIVE
"With fewer moving parts, there
are fewer components to wear,
service, or fail. Direct-drive
systems are highly efficient, with
typical motor efficiency between
92 - 96% and propellers ranging
from 75 - 80%.
“The trade off for direct drive
motors is the motor must be
capable of producing the
required torque at the desired
propeller speed. This can
influence motor size, voltage,
current, and packaging, especially
in higher thrust applications.
In a geared thruster, the motor
drives the propeller through a
gearbox. This allows the motor to
operate at a higher, more efficient
RPM while the gearbox reduces the
output speed and increases torque
at the propeller.
Geared systems can be useful where
motor size, packaging, or power
density are major constraints. They
may allow a smaller high-speed
motor to drive a larger or slower-
turning propeller, depending on the
application.
The tradeoff is that the gearbox
introduces additional mechanical
components, lubrication
requirements, efficiency losses, and
potential wear points.
Geared systems can be effective in
the right application, but they do
add mechanical complexity," said
Rafeh.
GEARED
THRUSTERS
19
operating depth, available
power, thrust requirement,
mission duration, environmental
conditions, control requirements,
and long-term maintenance
strategy."
Apart from propeller diameter,
designers must also consider
blade count, blade geometry,
pitch, duct shape, and the
overall footprint of the thruster.
"There are many cases where
the required thrust could be
achieved with a larger
propeller, but the vehicle
simply does not have enough
available space," said Rafeh.
"In those situations, the design
challenge becomes finding the
best balance between thrust,
efficiency, size, weight, and
vehicle integration.
"In some applications, the
priority may be a small,
compact, lightweight thruster.
Other applications can
accommodate a larger
package, creating different
tradeoffs between efficiency,
propeller size, duct profile, and
the amount of useful thrust
produced from the available
input power.
The best choice depends on the
complete vehicle requirement.
Direct drive may be preferred
for simplicity, response, and
serviceability, while geared
designs may be considered
where packaging, motor speed,
or torque requirements make
gear reduction
beneficial.
Last year,
SEAMOR Marine
launched the
Sturgeon 200
geared thruster, a
powerful modular
propulsion
system, with
integrated speed
control, designed
for remotely operated vehicles
(ROVs), autonomous underwater
vehicles (AUVs), and unmanned
surface vessels (USVs) where power
conservation is critical.
The “The upside is that eliminating
the gearbox reduces mechanical
complexity and avoids the
efficiency losses associated
with gear reduction. is
available in a standard
24-volt configuration, with 48-
volt options for applications
requiring additional power.
Its electrical components are
protected by a NASA-featured
Bal Seal nose cone assembly
and housed in a high-strength,
corrosion-resistant 6061
Aluminium casing that avoids
the pitfalls of fully-flooded or
designs.
20
20
"That is why thruster design is rarely about one
component by itself. The motor, propeller, duct,
vehicle shape, and operating condition all have
to work together as a complete propulsion
system."
Ducted thrusters use a surrounding nozzle or
housing around the propeller. The duct can
help protect the propeller, improve safety and
in many cases increase low-speed thrust by
controlling how water enters and exits the
propeller.
The benefit of a duct depends heavily on the
vehicle and mission profile. For ROVs that
operate at low speeds, perform station
keeping, or require high bollard thrust, a
ducted thruster can be a practical and efficient
solution. For faster-moving AUVs or survey
vehicles, however, the added drag of the duct
may outweigh the lowspeed thrust benefit.
"When a vehicle such as an AUV operates
continuously at higher forward speeds, the drag
penalty of a duct becomes much more
important," said Rafeh. "For heavier ROVS that
operate at lower speeds, where total vehicle
drag is already high, the protection and low-
speed thrust benefits of a duct may be more
valuable."
Duct geometry is also an important design
consideration. The shape of the inlet, outlet,
and internal profile can affect thrust, efficiency,
cavitation behaviour, and how cleanly the jet
exits the thruster. A well-designed duct must
work together with the propeller rather than
simply act as a protective ring.
Rim-driven thrusters share some visual similarities
with ducted thrusters because the propeller is
integrated into an outer ring, but they are a different
architecture. Instead of driving the propeller from a
central shaft or hub, the motor drives the rotor
around the outside diameter.
"This can reduce shaft-related sealing concerns and
may reduce entanglement around a central hub, but
it also introduces tradeoffs in efficiency, thermal
management, manufacturing tolerances, and debris
sensitivity.
"In real-world subsea conditions, the most efficient
thruster on paper is not always the best solution,"
said Rafeh. "If the vehicle is operating in kelp,
fishing line, sediment, or biological fouling, reliability
and resistance to entanglement can become just as
important as peak efficiency."
DUCTED THRUSTERS
Innerspace Electric thruster
THRUSTERS