Subsea Engineering Design

J+S delivers multi-disciplinary subsea engineering design services supporting the development, modification and life extension of critical subsea infrastructure. Our experienced engineering team combines practical offshore experience with advanced design and analysis capabilities to deliver reliable, cost-effective solutions tailored to specific project requirements.

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J+S Subsea hydraulic control panel used for subsea control system testing, diagnostics and operational support.

Subsea Engineering Design Services

Specialist subsea engineering design services for offshore energy, decommissioning and renewable projects.

From concept development through to detailed design, manufacture and testing, J+S provides specialist engineering support for a wide range of subsea control, power distribution and connectivity systems.

Using advanced 3D modelling and engineering analysis tools, our team develops bespoke solutions that improve reliability, address obsolescence challenges and support both new-build and brownfield projects.

Our engineers work closely with operators, OEMs, EPC contractors and offshore service providers to deliver practical solutions that can be manufactured, deployed and maintained efficiently throughout the asset lifecycle.

Subsea Control System Capabilities

Our expertise spans the design, integration, refurbishment and support of critical subsea control infrastructure for offshore energy, decommissioning and marine renewables projects.

J+S Engineering Design

Concept & Detailed Design

Development of subsea equipment and systems from initial concept through to fully detailed manufacturing packages.

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3D Modelling & Product Development

Creation of detailed 3D models and assemblies using SolidWorks, supporting design reviews, rapid prototyping and manufacture.

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Subsea Control System Design

Engineering support for subsea control modules, distribution systems, communication systems and associated infrastructure.

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Connectivity & Interface Design

Design of electrical, hydraulic and fibre optic connection systems including cable assemblies, stab plates and interface equipment.

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Obsolescence Resolution

Engineering studies and redesign solutions to replace obsolete components while maintaining system functionality and reliability.

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Fault Investigation & Remediation

Technical investigations, root cause analysis and engineering solutions to resolve equipment failures and performance issues.

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Key Engineering Services

J+S provides specialist engineering support across a wide range of subsea applications including:

  • Production control system support
  • Bespoke subsea product design
  • Equipment obsolescence management
  • Reverse engineering of legacy equipment
  • Fault diagnostics and remediation strategies
  • Offshore intervention procedure development
  • Control system power analysis studies
  • HV cable splicing and termination design
  • Subsea Control Module (SCM) testing and refurbishment support
  • Mechanical and electrical integration studies
  • Design for manufacture and assembly (DFMA)
  • Prototype development and testing

Equipment & Systems Expertise

Our engineering team has extensive experience supporting the design, modification and life extension of a broad range of subsea equipment.

Control Systems

  • Subsea Control Modules (SCMs)
  • Subsea Control Manifolds
  • Electrical and hydraulic distribution units
  • Chemical distribution units

Power Distribution Equipment

  • Single-phase transformers
  • Three-phase transformers
  • High-voltage subsea power systems
  • Electrical distribution infrastructure

Connectivity Systems

  • Electrical jumpers
  • Hydraulic jumpers
  • Fibre optic assemblies
  • Electrical and fibre cable splice assemblies
  • Electro-hydraulic stab plates

Umbilical & Termination Systems

  • Umbilical Termination Assemblies (UTAs)
  • Manifold Termination Units (MTUs)
  • Cable repair systems
  • Pressure-balanced housings
  • Single-atmosphere housings

Featured Engineering Projects

Real-world examples of how J+S engineering design capabilities deliver results for our clients.

10 J+S Case Study SCM Communications for Decommissioning 1

SCM Communications Upgrade

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

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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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Manual Subsea Control Module Development

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

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Why Choose J+S?

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

Multi-Disciplinary Engineering Expertise

Mechanical, electrical, hydraulic and fibre optic engineering capability under one roof.

Practical Offshore Experience

Engineering solutions developed with real-world installation, operation and maintenance requirements in mind.

Independent Solutions

Flexible engineering support tailored to project requirements rather than tied to specific OEM equipment.

Full Lifecycle Support

From concept and design through manufacture, testing, refurbishment and operational support.

Rapid Response Capability

Engineering teams available to support urgent operational issues, obsolescence challenges and equipment modifications.

Engineering Support for Your Next Project

Whether you require support with a new subsea development, equipment upgrade, obsolescence challenge or life extension programme, our engineering team can provide practical solutions tailored to your operational requirements.

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Contact Our team
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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