Abstract This paper describes the development of the Smedvig Production Unit (SPU) 380, a new FPSO (Floating Production, Storage and Offloading) concept. The paper outlines how a market analysis was combined with a business strategy to arrive at a certain set of design parameters and capacities. With this as input the project team prepared an Outline Specification for a fully integrated production vessel. The Outline specification further termed the input for the Basic Engineering work. Within a time frame of 13 months the project was brought from an idea to the actual ordering of the first SPU 380. Introduction The industry is presently witnessing a remarkable boost in the interest for Mobile Production Systems. Mobile Production Systems are either monohull FPSOS (Floating Production Storage and Offloading), semisubmersible FPVS (Floating Production Vessels) or JUPVS (Jack-up Production Vessels). The increased interest for FPSOS was particularly seen in 1994 when a number of vessels was ordered by oil companies and contractors. Through 1993 and 1994 several designs were developed of which a certain number of purposebuih FPSOS are now about to be realized for start-up of operations in 1996 and I997. One of the concept designs that was developed during this period was the Smedvig Production Unit (SPU) 380, a medium size FPSO capable of storing 380,000 bbls of crude oil and with a nominal production capacity of 50,000 bbls of oil per day. Ref. Fig. 1- SPU 380 Artistic Impression. This paper describes tbe 13-month development of the SPU 380, starting in March of 1993 and ending in April of 1994 when the first SPU 380 was ordered from Far East Livingston Shipbuilding in Singapore. Market Analysis -1 month The FPSO as a concept has generally developed from the need to find viable solutions for development of the smaller fields, say for recoverable reserves of less than 50 mill. bbls. Over the last 15 to 20 years the industry has seen a number of tanker conversions adapted to meet the criteria of small fields. In general the project model has been for oil companies to buy a second-hand tanker, convert it and produce the field for a certain number of years. The average production life time has been in the range of 3 to 7 years. Although some of the vessels have been redeployed for a second production application they have normally been planned for one specific field application only. Over the last 10 years contractors have seen this as aninteresting business opportunity. One vessel might be designed with sufficient flexibility to serve a number of the smaller fields, The business strategy is then for the contractor to own and operate the vessels and thus offer a service rather than the facilities as such.