The SSP-300: An Alternative to the Oil Industry

Abstract

Abstract The SSP (Sevan Stabilized Platform) is basically a mono-hull with circular shape, depending on the same stability principles as a ship-shaped vessel. The SSP-300 refers to one SSP hull size, capable of storing 300,000 barrels of cargo. Differently than the SPARs, the SSP is wider than her vertical height, with an operational draft that is typically less than one third of her diameter. The circular shape dispenses the unit of any heading changes, since the seas face the same vessel hydrodynamical resistance, whichever direction they are coming from. Consequently, the SSP does not need turrets nor swivels, in order to handle the incoming oil flow, having the option of receiving the risers through a central moon-pool, while maintaining a spread-mooring system separately deployed from her outer hull. The design also includes important safety features, like double bottom and double sides, which allows for segregated ballast and offers structural strengthening. The highly symetrical shape is also conducive to modularity and a good stress distribution throughout the hull, preventing fatigue stress concentration and doing away with the need of using high grade steel. The result is that the hull is composed of a small number of different construction modules, used repeatedly, and a lower steel density for the hull, which translates readily into smaller construction cost and yard time. The SSP not only offers all the advantages of a regular ship-shaped vessel – like large storage capacity, big deck load, and spacious deck area – but has motion behaviour similar or better than a semi-submersible hull. Construction is facilitated by the intrinsic symmetry, which also offers access to all tanks from a central position, thus reducing piping and cabling. This paper will address these, and other features of the SSP (including the structural economies allowed by the design), describing a concept design that can be constructed virtually anywhere, and with enough robustness to compete sucessfully in a wide range of applications, throughout the world.