Enabling offshore flexibility: Portable spreads unlock West Africa operations

ALEXANDER WILSON, Maritime Developments Ltd. 

Access to offshore installation vessels has become one of the defining constraints in today’s energy market. As global demand for subsea infrastructure grows across both traditional oil and gas and emerging energy sectors, competition for specialist assets is intensifying—particularly in regions such as West Africa and Brazil where vessel availability, scheduling and mobilization all carry added complexity. 

Fig. 1. MDL deployed a full flex-lay spread optimized for a deepwater jumper installation offshore Angola.

Against this backdrop, operators and contractors are increasingly rethinking how projects are executed. Rather than relying exclusively on large, dedicated installation vessels, there is a growing shift towards augmenting more readily available construction tonnage with modular, high-capability back-deck equipment. 

Experience offshore Angola and Congo. This approach is already being applied in practice.  

A recent example includes Maritime Developments Ltd. (MDL) supporting DOF Subsea on consecutive SURF (subsea, umbilicals, risers and flowlines) projects offshore Angola and Congo, Fig. 1. This project demonstrated how portable flex-lay spreads can be adapted for varied project requirements while maintaining continuity in equipment, engineering approach and offshore execution. 

MDL supplied its Generation 3 Reel Drive System, high-capacity Horizontal Lay System (HLS-400), four-track tensioner, and 55Te A&R winch with associated wire package for installation of a 10-in. flexible water injection jumper in approximately 1,700 m of water. The work was executed using DOF’s I-Class vessel Skandi Installer, enabling deployment of a full flex-lay spread optimized for deepwater installation. 

The follow-on shallow-water scope in Congo covered the installation of flexible lines and composite submarine cables from 16 reels. The MDL Generation 3 RDS and four-track tensioner were deployed alongside HLS-200—a compact package to allow more space on deck to accommodate the larger number of reels and products on the mission. The 55Te unit from MDL’s Winches & Lifting Solutions was supplemented by its two 15Te tugger winches.  

While the two projects shared core elements of the flex-lay spread, the handling requirements differed between the deepwater Angola installation and the shallow-water Congo scope. Being able to deploy alternative horizontal lay system configurations, while maintaining continuity in the wider spread and vessel selection, allowed the team to adapt efficiently between projects—evidenced by completion of the second scope ahead of schedule. 

Fig. 2. MDL’s Horizontal Lay System integrates multiple handling functions in a single modular frame.

Flex-lay spreads beyond West Africa. This capability extends far beyond these two projects. Modern portable spreads can support a range of offshore scopes without requiring a complete rethink of vessel strategy or equipment philosophy each time. Repeated use of familiar equipment, deck plans and mobilization methodologies can reduce engineering hours, shorten critical path activity and help contractors maximize vessel utilization across multiple projects, Fig. 2.  

This is particularly valuable in regions where access to specialist vessels may be limited and where the commercial success of a campaign often depends on keeping mobilization and offshore time under control. 

West Africa presents exactly this kind of challenge. The region combines deepwater developments, brownfield modifications and shorter tie-backs, often under commercial and logistical constraints that do not favor large, dedicated installation vessels. At the same time, vessel supply remains tight, making it difficult to secure suitable assets on schedule. The result is a need for offshore execution models that are more agile, more adaptable and less dependent on one class of vessel. 

Portable, high-capability back-deck spreads provide an alternative in these conditions. One key component in MDL’s portfolio is the Horizontal Lay Systems, which integrate multiple handling functions into a single modular frame. The HLS allows contractors to undertake installation and recovery scopes that would traditionally point towards a much larger spread of equipment or a more specialized vessel solution. 

Fig. 3. MDL’s Generation 3 RDS delivers efficient and compact reel handling on deck.

The real differentiator lies in the line-pull capability achievable within a compact system using high-capacity tensioners. More demanding deepwater or flexible installation scopes have traditionally driven contractors towards vertical lay system (VLS) vessels or dual-tensioner arrangements. Those solutions are effective, but they also come with vessel, space and cost implications. Combining compact HLS architecture with high-capacity tensioner technology creates a solution that is portable, modular and better-suited to constrained vessel environments.  

The Reel Drive System, Fig. 3, then complements this capability by providing efficient and compact reel handling on deck. MDL’s Generation 3 RDS, with features including an integrated track and cradle system and built-in power unit, is designed to significantly reduce sea-fastening requirements and mobilization time—and therefore costly time in port.  

None of this works on equipment alone. MDL supports its customers through early engineering engagement, ensuring a clear understanding of how each solution integrates with the selected vessel and overall project scope. By aligning deck layouts, lift plans, sea fastening and mobilization methodology with offshore procedures from the outset, MDL develops solutions tailored to real-world constraints—enabling equipment that is suited to the application. 

This approach gives operators and contractors more control over how offshore scopes are delivered. Rather than fitting the project to a narrow band of vessel availability, operators can build a capable spread around the realities of the campaign and the assets available.  

Portable spreads are, therefore, not just a workaround for vessel shortages. Increasingly, they represent a more deliberate model of offshore execution: one that uses engineering, modularity and versatile technology to unlock efficient project delivery across installation, recovery and wider subsea campaigns.  

For an industry that needs to keep moving despite ongoing asset constraints, that flexibility is becoming a strategic advantage.  

ALEXANDER WILSON serves as head of Flexlay Solutions at Maritime Developments Ltd. (MDL). With more than 12 years of experience encompassing drafting, project engineering, delivery management and technical sales, Mr. Wilson brings a comprehensive understanding of offshore operations and MDL’s portfolio of technologies. His robust technical background and proven problem-solving acumen have positioned him as a trusted leader, supporting project teams in achieving operational excellence throughout the entire field lifecycle.