Abstract: A modular offshore hydrocarbon production, storage, and loading system, which includes an assembly of cylinders rigidly connected together, with the cylinders including at least one metal floatation cylinder adapted to occupy a vertical position in use. A bottom of the cylinder is situated below a level of the water and a floatation cylinder surrounded by several metal peripheral cylinders which descend below the floatation cylinder and define, with the bottom of the floatation cylinder, a free space for accommodating at least one member for rigidifying the system. The peripheral cylinders include metal oil storage cylinders, with the storage being effected on a water column communicating with the water surrounding the system, and metal ballast cylinders or parts of cylinders filled with oil, water, air or inert gas.

Abstract: A connection system between a main body and a superstructure, usable in a sea environment, comprising an arrangement for moving the main body relatively to the superstructure and, guide means cooperating with said moving arrangement. The moving means arrangement is inscribed on a cylindrical surface, was the guide and moving arrangment being adapted to allow at least a swinging movement of main body relatively to said superstructure.

Abstract: A modular offshore hydrocarbon production storage, and loading system, which includes an assembly of cylinders rigidly connected together, with the cylinders including at least one metal floatation cylinder adapted to occupy a vertical position in use. A bottom of the cylinder is situated below a level of the water and a floatation cylinder surrounded by several metal peripheral cylinders which descend below the floatation cylinder. The peripheral cylinders include metal oil storage cylinders, with the storage being effected on a water column communicating with the water surrounding the system, and metal balast cylinders or parts of cylinders filled with oil, water, air or inert gas.

Abstract: The present invention concerns a realization procedure of a modular system particularly suitable for use off coasts, this system comprising a set of cylinders (A.sub.1, A.sub.2, A.sub.3 . . . ) rigidly linked together, this set including at least one central cylinder (A.sub.1) and a plurality of peripheral cylinders (A.sub.2, A.sub.3 . . . ).This procedure includes the following successive stages:the assembling together at the quay (8) of at least two peripheral first cylinders (A.sub.4 and A.sub.5),a joining of the central cylinder (A.sub.1) to these two peripheral cylinders (A.sub.4 and A.sub.5),the placing in water of the unit constituted by the said central cylinder (A.sub.1) and the said peripheral first cylinders (A.sub.4 and A.sub.5) and, the said unit being placed in the water, the joining of any remaining peripheral cylinders (A.sub.2, A.sub.7, A.sub.8) to the said unit (A.sub.1, A.sub.4, A.sub.5).The invention can be advantageously used for the realization of a petrol production platform off coasts.