Subsea Control Systems

J+S provides specialist engineering support for subsea control systems throughout the asset lifecycle, from concept development and equipment manufacture through to refurbishment, upgrades, operational support and life extension programmes.

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7 J+S Case Study Manual Subsea Cable Retaining Device

Subsea Control System Expertise

Design, integration, refurbishment and support of critical subsea control infrastructure for offshore energy, decommissioning and renewable projects.

Subsea control systems are critical to the safe and reliable operation of offshore assets, enabling communication, power distribution, monitoring and control between topside facilities and subsea equipment.
J+S supports operators, OEMs and offshore contractors with specialist expertise across electrical, hydraulic and fibre optic subsea control infrastructure. Our team provides engineering, refurbishment, testing, integration and operational support services that help maximise reliability, extend equipment life and reduce operational risk.
With extensive experience across brownfield and greenfield developments, we deliver practical solutions for both legacy systems and new-build projects.

Our Subsea Control System Capabilities

Subsea Connectivity Systems

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Subsea Distribution Systems

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Subsea Control Manifolds

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High Voltage Subsea Systems

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Subsea Transformers

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Subsea In-Line Splice Assemblies

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Lifecycle Support Services

Our support extends beyond equipment supply and design.
We provide specialist services throughout the operational life of subsea control systems including:

  • Engineering design and modification
  • Equipment refurbishment and recertification
  • Obsolescence management
  • Fault diagnostics and investigation
  • Factory acceptance testing (FAT)
  • Offshore support and commissioning
  • Strategic spares management
  • Decommissioning support

This integrated approach enables operators to maximise equipment performance while reducing lifecycle costs.

Equipment & Systems Supported

J+S has experience supporting a wide range of subsea control and power distribution equipment including:

Control Equipment

  • Subsea Control Modules (SCMs)
  • Subsea Control Manifolds
  • Master Control Stations
  • Communications Systems

Power Distribution Equipment

  • Electrical Distribution Units
  • Hydraulic Distribution Units
  • Chemical Distribution Units
  • High Voltage Distribution Systems

Connectivity Systems

  • Electrical jumpers
  • Hydraulic jumpers
  • Fibre optic assemblies
  • Umbilical Termination Assemblies
  • Cable Splice Assemblies

Power Conversion Equipment

  • Single Phase Transformers
  • Three Phase Transformers
  • Subsea Power Distribution Infrastructure

Featured Subsea Control System Projects

Real-world examples of how J+S Controls system deliver results for our clients.

10 J+S Case Study SCM Communications for Decommissioning 1

SCM Communications

Engineering support for high-voltage subsea power distribution and offshore renewable applications.

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Manual Subsea Control Module Development

Design, assembly and refurbishment of subsea cable splicing and connection systems.

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UTA and SDU System Upgrade

Engineering support for high-voltage subsea power distribution and offshore renewable applications.

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Why Choose J+S?

he engineering partner you can rely on for practical, cost-effective subsea solutions.

Multi-Disciplinary Engineering Team

Electrical, hydraulic, fibre optic and mechanical expertise under one roof.

Proven Offshore Experience

Supporting offshore energy projects worldwide.

Independent Technical Expertise

Support for OEM and non-OEM equipment across a wide range of subsea systems.

Full Lifecycle Capability

Design, manufacture, refurbishment, testing and operational support services.

Rapid Response Support

Fast mobilisation for fault finding, intervention and operational challenges.

Need Support With Your Subsea Control System?

Whether you’re developing new infrastructure, upgrading existing equipment or addressing obsolescence challenges, our engineering team can help.

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Mark Patterson Non-Executive Chair

Mark Patterson

Non-Executive Chair

Mark’s career spans five decades, marked by entrepreneurial success and visionary leadership across various sectors, including offshore marine technology, subsea oil and gas, green energy storage, and more.

With a track record of leading businesses through start-up, growth, acquisitions, and transformations, Mark’s expertise lies in strategic decision-making, mentoring, and brand management.

He has overseen multimillion-pound projects, pioneered new technologies, and guided companies to international recognition, such as the underwater GPS NASNet®.

His leadership style is direct, inclusive, and based on trust, empowering teams to excel.

Mark’s achievements include managing high-profile global companies, such as Balmoral group, Nautronix and Well-Safe Solutions, where he played key roles in groundbreaking projects. Global explanation and high growth.

Outside of business, Mark is deeply committed to family and charity work, with a passion for shooting, boating, and car collecting. As an experienced executive, he remains dedicated to fostering success by identifying future opportunities and mentoring the next generation of leaders.

Mark Patterson Non-Executive Chair

Mark Patterson

Non-Executive Chair

Mark’s career spans five decades, marked by entrepreneurial success and visionary leadership across various sectors, including offshore marine technology, subsea oil and gas, green energy storage, and more.

With a track record of leading businesses through start-up, growth, acquisitions, and transformations, Mark’s expertise lies in strategic decision-making, mentoring, and brand management.

He has overseen multimillion-pound projects, pioneered new technologies, and guided companies to international recognition, such as the underwater GPS NASNet®.

His leadership style is direct, inclusive, and based on trust, empowering teams to excel.

Mark’s achievements include managing high-profile global companies, such as Balmoral group, Nautronix and Well-Safe Solutions, where he played key roles in groundbreaking projects. Global explanation and high growth.

Outside of business, Mark is deeply committed to family and charity work, with a passion for shooting, boating, and car collecting. As an experienced executive, he remains dedicated to fostering success by identifying future opportunities and mentoring the next generation of leaders.

Phil Reid Managing Director J+S-Subsea

Phil Reid

Managing Director

Phil has worked in the energy industry for over 25 years. He started his career with Kvaerner FSSL progressing through a variety of roles in subsea engineering, from manufacturing to leading some of their most complex projects all over the world. He worked with the original J+S for a period before moving on to Genesis Oil and Gas as a Subsea Controls Engineering consultant; during that period, he was seconded to Centrica Energy (now Spirit Energy) which led to a permanent role as Lead Subsea Controls & Umbilical Engineer for Developments, Capital Projects and Operated Assets. For almost a decade Phil successfully delivered Capital Projects from concept right through to project close out whilst also looking after the running of their subsea assets.

As part of J&S Subsea limited, Phil oversees the day-to-day operations and will grow the business both in the UK and globally. 

James Morris

Engineering Director

James’s career started when he joined the Royal Navy from school as an Artificer Apprentice. After a 5-year Marine Engineering Apprenticeship he served in surface ships HMS Glamorgan, HMS Edinburgh, and HMS Glasgow and at Rosyth as part of an engineering support team. 

Moving into the Energy Industry in 1992, over the next 26 years he gained a wealth of experience within large and small companies on operation, design and project management of subsea control systems and equipment. This period started with several years as a Project Engineer for a family run hydraulic services company Grampian Hydraulics followed by 5 years as a Support Engineer at Kvaerner Oilfield Products.  James joined RRC Controls Services ltd in 2001 before finally moving to J+S Ltd in 2010. At J+S his dedication and technical capabilities were rewarded with several promotions until becoming a member of the management buyout team. 

He has designed an extensive array of subsea equipment from basic cable penetrators to complete subsea control modules. 

James thrives on providing solutions for client’s problems. 

As Engineering Director, James will ensure that the company provides clients with timely, cost effective and technically sound solutions and services. 

Matthew Blair

Executive Chairman

Matt Blair is Executive Chairman of J+S Subsea which was formed in October 2020 through a management buyout of the Subsea Engineering Division of Systems Engineering and Assessment Ltd.

With J+S Subsea and SEA for over 14 years, Matt has a wealth of industry knowledge and expertise.

Previously an Electronics Engineer with Ferranti Computer Systems Ltd specializing in sonar and submarine command systems, Matt moved into hydrographic survey working with Subsea7, Tritech, and CDL before joining J+S Subsea.

He was Vice Chair of the Decom Leadership Group of Decommission and in that role, he facilitated industry and academic studies on potential for reuse and repurposing of decommissioned equipment. He is still actively involved with the reuse agenda through Decommission and OEUK.

Although not part of day-to-day operations, Matt stays close to company strategic matters and is seeking further opportunities to update and transfer Energy technologies and products into the Marine Renewables markets and help to develop the broader circular economy.

Contact Us

  • J&S Subsea Limited
  • The Lombard Centre
  • Kirkhill Place
  • Dyce
  • AB21 0GU
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