Case Study

Successful delivery of more than 41 km of complex umbilicals to project in the North Sea.


Oil and Gas




Europe & Middle East

In May 2022, Oceaneering successfully delivered the final piece of hardware on a multi-item project scope for a major operator in the North Sea.

Starting with a front end engineering and design study in 2017, the project included major milestones and industry-first. The team supplied more than 41km of umbilicals, flying leads and ancillary hardware to meet the client’s requirements.


The project presented several significant challenges.

The dynamic umbilicals included a 2 ½ inch steel tube in their cross section design, prompting the need to transform the manufacturing capabilities at the Rosyth site with the installation and commissioning of a purpose-built large bore tube welding line.

There was also a design requirement to include a direct current/fiber optic (DC/FO) cable in the dynamic umbilicals. As our team understands, this marked an industry-first integration. The complexity surrounding these delicate components demanded precision and advanced engineering.

Our Solution

Planning was essential to the project’s successful completion. Process engineers developed the plans, using input from our Panama City site, to design the large bore tubing welding line.

The Manufactured Products team in Houston was responsible for many of the larger pieces of ancillary hardware, and the technical solutions engineers in Rosyth worked to optimize the umbilicals’ cross sections designs.

All umbilical manufacturing was completed in Rosyth, and extensive engineering interface management was required at every stage of the project, from kick off to packaging and load out of the reels. Project management was pivotal in handling the more than 100 interfaces created by such a complex scope.

Execution Plan

From February to July 2017, the technical engineering team completed a complex and thorough front end engineering and design (FEED) study for the client.

The FEED study demonstrated Oceaneering’s extensive understanding of subsea umbilicals and hardware, manufacturing capability, and experience and Oceaneering was awarded the project’s contract in December 2017.

Upon award, preparations to transform the manufacturing capabilities at the Rosyth facility were started. Drawing on lessons learned and using equipment previously installed at the Panama City umbilical manufacturing site, the local team designed and installed a large bore tube welding line. The complexities of this foundational work were extreme and demonstrated ingenuity and experience. The project schedule was built to meet the staggered delivery dates required by the customer.

The large bore welding line was successfully commissioned in 2019, enabling the welding of 2 ½ inch, 10-meter-long straights that would later be integrated to some of the project’s umbilicals.

Manufacturing on the project's umbilicals started with the completion of the welding line 2019 and ran through 2021. Ancillary equipment, flying lead termination heads including Oceaneering M1 junction plates, and subsea umbilical termination assemblies were manufactured at Oceaneering’s Manufactured Products facility in Houston and shipped to Rosyth for integration with the umbilicals.

Specialist technicians completed the umbilical cross section testing on site at Rosyth’s Testing, Qualification, and Reliability Laboratory. Samples of product underwent bend stiffness, combined tension with bed, crush, and flex fatigue testing to prove their performance factors met the required design criteria.

On the 29th of May 2021, the Oceaneering team in Rosyth (SDS-R) delivered the first two dynamic umbilicals. The final deliverable, a dynamic spare, left quayside in late May 2022, marking the culmination of the project.


The team successfully delivered 41.64 km of product made up various cross sections manufactured into:

  • 3 Dynamic umbilicals (inclusive of 1 spare)
  • 7 Production umbilicals
  • 1 Production umbilicals incorporating DC/FO cables
  • 2 Water injection umbilicals
  • 2 Water injection umbilicals with DC/FO cables
  • 5 Infield cables
  • 6 Hydraulic flying leads
  • 2 Fiber optic flying lead
  • 12 Low voltage electrical flying leads
  • 4 SA DC/FO cables
  • 2 PRM FO cables

An array of ancillary hardware was also supplied as part of the contract. This included, but was not limited to, flying lead termination heads incorporating Oceaneering M1 junction plates, umbilical termination assemblies, mudmats, pulling heads and hang off collars, dynamic bend stiffeners, buoyancy modules, tie back collars, tie down collars, free-issued umbilical termination heads, and a variety of repair kits and spare parts.


The final spare umbilical delivery in May 2022 marked the final milestone in a transformative project for the Rosyth site.

From commissioning a large bore tube welding line to completing the industry-first integration of DC/FO cables, the project provided the global and local teams with significant opportunities for lessons learned and demonstrated the Oceaneering can-do attitude.

The project was completed during the challenging circumstances of the Covid 19 pandemic and relied heavily on Oceaneering’s positive relationship with both the client and suppliers.

The client is now equipped with the infrastructure required to achieve first oil. They, too, have improved their understanding of the complexities involved with such challenging cross sections, but have been reassured and encouraged by the successful, safe completion of the project scope.

Ready to learn more?

With world-class global manufacturing facilities and industry experience, we meet your complete subsea distribution requirements with optimized solutions.

Contact Us

Our team of experts is ready to help you get started.

Oceaneering offers best-in-class products and solutions, backed by unparalleled quality, reliability, and global support. Fill out the inquiry form to start a conversation today.