Abstract: A platform device comprising an underwater structure equipped wth a base resting upon the bed of a body of water, and a bridge carried by said structure above the surface of the body of water, characterized in that the underwater structure comprises, in the base or in proximity thereof, a plurality of chambers which can be kept dry and can be isolated from one another, said chambers being equipped wth access means and being suitable to receive devices or apparatus connected to a network of piping systems placed upon the bed of the sea.

Abstract: A device for protecting the base of a structure resting or constructed on the bed of a body of water against undermining, comprising a curtain which extends without interruption parallel to the base of the structure at a certain distance therefrom in the direction of the body of water, characterized in that said curtain is an imperforate wall extending from the ground upward to a height which is but a minor fraction of the depth of the body of water whereby the whole of the wall is deeply immersed in the water.

Abstract: The present invention relates to devices for laying submarine pipelines, in which the pipeline, associated with floats attached to it at intervals, the whole assembly being contrived in order to produce a certain buoyancy, is equipped with chains resting upon the bed of the body of water and performing the function of a guide rope. The weight of those parts of the chains extending between the bed of the body of water and the pipeline, maintains the latter submerged at a certain distance above the bed of the body of water and the pipeline can be towed, for example by means of a tug, without any risk of it being damaged by striking said bed.The improvement which forms the object of the invention consists in attaching the chains or their equivalent, for example cables, not merely to the pipeline itself, but also to the floats.

Abstract: In order to pass a duct across a wall between two spaces in which different pressures prevail, there is formed in said wall a passage which is temporarily closed off by means of a panel applied in position by the pressure, whereafter, at the time at which the duct is to be passed across the wall, the pressures in the two spaces are equalized making it possible to remove the temporary closure, the duct is introduced through the passage, a temporary seal between the passage and the exterior of the duct is formed, the pressure difference between the two spaces is restored, and a final seal between the passage and the exterior of the duct is created.

Abstract: A structure designed to rest upon the bed of a body of water, in particular to support fixed installations such as an off-shore drilling platform, comprising a central cavity without a base and surrounded by a double vertical wall spaced apart by vertical partitions, preferably of cylindrical shape, forming a plurality of compartments provided with bases at their bottom ends and extending above the double wall.

Abstract: A platform structure for maritime installations, designed to rest under its own weight upon the seabed through the medium of a base acting as the foot of a tower surmounted by an emergent superstructure, comprising a strong, watertight tubular member incorporated into the structure in order to form a shaft or chimney extending from top to bottom of the structure in order to protect the components of the installation against corrosion and shock loading, and in order also to make it possible to carry out in the dry the various operations required by the process. The tubular member can be used without a base in order to give direct access to the seabed. Preferentially, the tubular member will communicate with one or more radial, watertight tunnels formed in the base.