Global Conversion of Fleet of Vessels for Offshore Construction



McDermott International gave Allswater the chance to flex their ship conversion muscles with this multi-phase, multi-continent project. Three vessels, two cable layers (Emerald Sea & Agile) and one platform supply vessel (Thebaud Sea), were converted into offshore construction vessels. The work was conducted in phases over four years in Canada, Dubai, Singapore and Indonesia.

Work conducted during this conversion project included: development of engineering drawings (structural, engineering systems and electrical), stability and longitudinal strength, engineering and feasibility studies, project management and ship system design as well as onsite supervision.


  • Blending the new components and requirements with the ships’ existing structures and layouts required a deep expertise and a unique approach.
  • With work taking place in three continents the project team overcame challenges with time zones, cultural differences and vendors and suppliers located around the world.
  • Ensuring the newly minted offshore construction vessels met the stringent intact and damage stability requirements to obtain the “Special Purpose Ship” designation meant a heightened attention to detail and continuous refinement of the designs.


Allswater’s Atlantic Canadian location proved very beneficial for working internationally. Being four hours behind the UK and two hours ahead of Houston, Allswater was able to address issues with European suppliers prior to the start of the workday in the US.

Each of the three vessels were strategically redesigned by the Allswater team to maximize capabilities in their new construction roles. Of the numerous installations and upgrades, the most significant included: Helideck installations, a large moonpool, a cable carousel, new machinery spaces, Saturation Dive Support system, accommodation units and crane installations.

In addition to the actual engineering, which was completed at the Allswater office in Halifax, there was a clear need for onsite support at each of the four work sites. Allswater was there to deliver. It was all hands on deck – Allswater had personnel working globally 24 hours a day, seven days a week, ensuring the project work was progressed efficiently.


Allswater’s ‘all in’ approach to partnering and working hand-in-hand with their clients ensured the engineering, and more specifically the construction, met the operational considerations, project schedule and budget constraints. All three converted vessels continue to provide offshore construction support to McDermott International’s offshore projects in the Arabian Gulf, Asia and Brazil.