One Stop FPSO - The Concrete Solution
Authors: Wood John , O&apos;Flynn Michael , Jones Roger , Wood Costain , Findlay Jim , Woodrow Taylor , Kernaghan John 
Published: October 2008

Abstract
A Floating, Production, Storage and Offloading vessel with a concrete hull has been developed by a joint venture of Brown & Root BARMAC and Costain/Taylor Woodrow. The paperdescribes the rationale behind the selection of concrete for the hull, the design development, the specific problems that needed to be solved, model tests, savings in capital and operating costs and the overall application for the vessel. The resultant design has been configured so that full fabrication can be completed in the BARMAC Nigg construction facility. This enables the vessel to be fully fabricated and commissioned at asingle site, the One Stop Option, resulting in savings on cost and schedule as all services are at hand, no time is spent intransporting the hull, work on both topsides and hull can be carried out concurrently and a fully commissioned vessel ready for production will be delivered. The design has beendeveloped to such an extent that "Approval in Principle" has been obtained from L10yds Register.
The formation of a joint venture between Brown & Root and Costain/Taylor Woodrow consolidates expertise in bothprocess and civil engineering so as to assure efficient and competitive production of all requisite facilities under an umbrella of total capability. Technical expertise available within the Brown & Root organisation has previously been applied in the design and construction of steel facilities in combination with the BARMAC alliance operating a flexiblecomplementary usage of yards at Nigg and Ardersier. The addition of Costain/Taylor Woodrow, together with Taywood Engineering Ltd as designer, provides an enhancement of total capability to include the prospect of the utilisation of concrete structures, where of commercial or structural preference. In many situations concrete is known to have both schedule and structural advantages, providing robust and rigid facilities with high insulation characteristics of a relatively maintenance freenature. Costain and Taylor Woodrow have a co-operative association over many years in the production of such, including recent work in the construction of a floating jetty for the Trident servicing project and gravity base tank for the BP Harding project, both 85,000 tonne structures for the marineenvironment.
The Brown & Root and Costain/Taylor Woodrow joint venture comprises a powerful and proven all embracing capability for the design, construction and commissioning ofconcrete FPSOs.

Background
Concrete vessels have and are increasingly being used for Floating Production Storage and Offloading vessels (Ref. 1, 2 & 3). The technical feasibility of these vessels has been proved to the extent that for the Schiehallion development, (Ref. 4) a concrete solution was pursued throughout the sanction processup to contract award.
At this time BARMAC received a number of tentative enquiries about the use of the Nigg dry dock for fabrication of a concrete vessel. At the start of 1996 discussions were held between BARMAC and the Costain/Taylor Woodrow joint venture, who had recently completed the concrete gravity base tank for the BP Harding Development.