Abstract The paper identities the advantages, features and applicability of a concrete hull for an FPSO and the issues related to project execution. For those considering the options for other fielddevelopments, the paper identifies the conclusions and the work on which these were based. The content of the paper is based on extended studies on the advantages, design features and feasibility of fabrication of thisnew design of FPSO hull. This work formed part of BPs review of options for the development of their Schiehallion field in 375 mctres water depth West of Shetland, the Atlantic Frontier. The conceptual design of vessel hull was carried out with the objective of providing the best solution for a concrete FPSO for BPs application. This included consideration of capital cost, system availability, operating costs, HSE aspects. Decommissioning and disposal, The flexibility of the concept e.g. for addition and modification during service were also examined. The design process was taken to the stage where these matters had been examined and the design has approval in principal for certification. During the design process the mathematical modelling of vessel motions and mooring forces were confirmed in tank tests. BP participated in the proof of concept, retaining the concept on their final short list of two options for the field development. It was concluded by all parties that this new concept had been full examined and proven technically. Introduction This paper has been produced by the Shetland Deepwater Alliance (SDA) with the cooperation and assistance of the BP Atlantic Frontier Programme (AFP) evaluation team. It draws together their shared views and conclusions on the use of concrete as a material for the hull of an FPSO, The following companies formed the alliance SDA for the BP AFP Stage 2 project; DORIS Engineering, Sir Robert McAlpine, Blue water, John Brown and Trafalgar House. During 1994 BP carried out a detailed evaluation process, in full compliance with the European Union regulations, to select a contractor to develop the concept of a concrete FPSO. Among the responding companies, SDA were placed ‘first in class’ for this work and, during the early part of 1995, were invited to tender this concept for Stage 2 of the Atlantic Frontier Programme in competition with other steel and concrete concepts. During the tendering process SDA was coached by BP. This allowed the teams working on the development to exchange views with the objective of achieving the optimum solution for this concept. Another of the benefits of this process was that both parties became familiar with the objectives opportunities and constraints in the design, construction, flexibility and service aspects of the concept A considerable amount of work was carried out by SDA in the development of a concrete hulled FPSO suitable for service West of Shetland. The concept was examined to optimise Capex, Opex, build schedule and flexibility to change during design/constnretion and when in service.