This paper describes the design of a semi-submersible floating production system in the Gulf of Mexico. The platform was designed to produce 100,000 barrels of oil per day in 2440 m of water. Detailed analysis for both 10 year and 100 year storms was performed, and a robustness check was done for a 1000 year storm. The design elements considered were; topside design, safety, buoyancy/trim, stability, loading, structure, cost, and mooring. The hull of the semisubmersible consists of four square columns with filleted edges and pontoons that connect the columns. The topsides were designed to hold the production equipment, helideck, lifeboats, and quarters and have 25m air gap from the waterline so that the platform can continue production in a 100 year storm. The hull displaces 61,000 metric tons, and is ballasted down to a 35 m draft in order to have an acceptable air gap. General Hydrostatics Software was utilized to make sure our semi-submersible complies with American Bureau of Shipping's stability rules for Mobile Offshore Drilling Units. The structural design was analyzed and refined using Visual Analysis, accounting for both static loading and dynamic loads. The analysis of the structure shows 17 cm deflections in both the topsides and the hull, which are acceptable. The mooring analysis was performed with OrcaFlex which was used to optimize the number of lines, line size, and line spacing based upon the American Petroleum Institute's (API) recommended practices. After conforming to API's guidelines, the optimal mooring system was composed of 12 chain-poly-chain lines anchored with suction piles. The total cost of the semisubmersible is estimated at $1.7 billion.

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