Maintaining subsea cable lay operations during asset transition

The challenge: keeping a committed vessel fully operational

N‑Sea Group had invested in a new 15‑tonne breakback tensioner from Royal IHC to support to support their critical cable maintenance and repair projects. Yet, while the new unit was progressing through build as planned, the lead time created a defined operational gap onboard their CURO vessel.

CURO, a multi-purpose DP2 vessel, was already committed to a demanding programme of subsea cable maintenance and repair projects. Any interruption to its cable lay schedule would have put contracted scopes and vessel utilisation at risk. For N‑Sea Group, the priority was to maintain operational momentum while waiting to transition to the new asset.

Key requirements included:

• A tracked tensioner suitable for different cable types and diameters
• Confidence that any interim solution could be integrated and removed without disruption
• Reliable technical support for vessel crews and project teams 

The solution: a rental tensioner to bridge the lead time

Our rental services team worked closely with N‑Sea Group to provide a long‑term rental tracked tensioner as an interim solution. The arrangement was structured to ensure continuity of operations throughout the planned transition period. As such, this went beyond equipment supply to include technical support at every stage, from mobilisation through the final swap-out.

Technical support we delivered

Over the 12-month hire period, the rental tensioner supported cable operations across several projects without interruption. Its suitability for different cable types and sizes also allowed CURO to move easily between different scopes.

Rental support included:

• Regular on-site maintenance assistance
• Remote diagnostics and technical guidance when required
• Responsive back‑office support for operational queries
• Mobilisation support for the changeover to the new-build tensioner

This continuous support ensured the rental tensioner was integrated on the cable lay vessel and the CURO crew were confident in running the equipment themselves, with support never far away.

The outcome: continuity of cable lay operations

Throughout the rental period, N-Sea Group could maintain their cable lay schedule with CURO as planned. The interim tensioner protected vessel utilisation and removed the risk of unnecessary programme disruption while the new tensioner was in build.

With on‑site and remote support from Royal IHC’s rental services team, CURO’s crew had consistent access to technical expertise throughout the hire period and during the final changeover. This support provided confidence that the equipment would perform as expected, issues would be addressed quickly, and the transition between systems could be executed without operational uncertainty.

With the new tensioner commissioned and now in full operation, CURO has since redeployed to support further international cable maintenance and repair projects. 

The impact: seamless changeover with no vessel downtime

When N-Sea Group’s new owned tensioner was ready for delivery, the transition was planned and executed during a single port call. Royal IHC operators supported the swift demobilisation of the rental unit and the installation of the new system.

As the rental solution had been configured with the end transition in mind, the changeover followed a plug-and-play approach. That meant no additional commissioning days were required, allowing CURO to return to operations without any lost vessel time.