Abstract: The invention consists of an apparatus for laying a pipeline, such as an oil duct or a gas duct, in a body of water, wherein the pipeline, or a section thereof, is enclosed within a ballast tube such that an intermediate space is formed between the pipeline or pipeline section and the ballast tube, said space being filled with a liquid less dense than water, such as a light hydrocarbon, while the pipeline is being laid, but may be filled, after the pipeline has been laid, with soft water or with a liquid heavier than water such as a grouting having a base of a hydraulic or hydrocarbon binder. The invention also comprises the provision of a plug at one end of an assembly of pipeline section and ballast tube whereby a free end of said assembly may be secured as by welding to a second assembly of pipeline section and ballast tube at a position remote from the liquid contained in the intermediate space in said first assembly.

Abstract: An off-shore gravity type platform for supporting a processing installation above the surface of a body of water and for housing processing components, comprising a pressure-resisting watertight central shaft extending from top to bottom of the platform structure, the lower end of the shaft being surrounded by a coffered base structure with a protective wall surmounted by pillars co-operating with the shaft for supporting a bridge, the shaft being so sized that the platform has a positive buoyancy, the top of the protecting wall being located below the level of the body of water, and the pillars being hollow and being filled with concrete after the platform is in place.

Abstract: An apparatus and method for towing a pipeline in a body of water to a place where the pipeline is to be laid on the bed of the body of water, the pipeline having a positive buoyancy and being provided with trail-ropes distributed therealong which drag on the bed while the pipeline is being towed and maintain it at a certain distance above the bed, wherein some at least of the trail-ropes are connected to the pipeline at points spaced apart therein in such manner that such trail-ropes are formed with arcuate portions extending between the points of attachment to the pipeline so that when said arcuate portions drag upon the bed they are retained substantially parallel to the longitudinal axis of the pipeline thereby to oppose drift by a transverse current, said trail-ropes also optimally comprising means for penetrating the bed so as to offer increased resistance to drift.

Abstract: A float device for use in laying a submarine pipeline from a launching base, comprising one or more tubes containing a liquid less dense than water, such as a hydrocarbon, and fixed to the pipeline so as to form therealong a plurality of compartments isolated from each other and each communicating with the sea via an opening or a pipe opening towards the bottom. Means may be provided for opening in each compartment a passage opening towards the top and for recovering the less dense liquid, driven by the water, to the outlet of said passages, or even for releasing the tube or tubes from the pipeline.

Abstract: For laying a pipeline on the bed of the sea, a plurality of pipeline sections are successively towed by a tug exerting a traction effort at a point spaced to the rear of the front end of a pipeline section being towed, while another tug exerts a holding effort at a point spaced in front of the rear end, the front and rear ends being maintained near to the surface by a system of floats and trail-ropes and the intermediate portion of the pipeline section being ballasted so as to be supported on the sea bed, whereafter the front end of the pipeline section is welded to the rear end of a preceding section, and so on.

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 by inflating a pair of inflatable seals, the pressure difference between the two spaces is restored, and a final seal between the passage and the exterior of the duct is created by injecting an adhesive cement between and into the inflatable seals.

Abstract: The invention relates to a method of laying submarine pipelines by submergence from the surface or from an adjacent level with one point of the pipeline being secured near to the surface so that the pipeline on being submerged comprises a section descending from this point towards the bed and connected by a curved section to the part of the pipeline already laid on the bed, in which weights are suspended from the pipeline at intervals thereon, at least at the time of its submergence, such that the assembly has a slightly negative buoyancy and the pipeline sinks slowly in the water until it is slowed down and stopped when the weights contact the bed, the weights thus acting as a guide rope.

Abstract: A method and apparatus for laying a submerged pipeline, such as a submarine pipeline, on the bed of a body of water along a path which crosses a ditch in said bed in which there is a current transverse to the pipeline, the depth of the body of water being at a maximum in said ditch and said pipeline being drawn along said bed from a shore towards open water, wherein at least one ballast tube is integrally associated with the pipeline so that a portion of said pipeline with the associated ballast tube takes up a position within said ditch in substantially U-form, the ballast tube being filled partly with air and partly with water which collects in the portion of the ballast tube of substantially U-form whereby the apparent weight of the pipeline is increased solely with respect to the portion thereof located in said ditch, the water remaining in position in the portion of the ballast tube temporarily located within said ditch as the pipeline and the associated ballast tube move forward during the laying operat

Abstract: For laying a submarine pipeline, hauling of the same is exerted by means of a force distribution cable which extends over the full length of the submerged part of the pipeline and which is attached to it by hangers, preferably in conjunction with heavy chains acting as guide ropes and anchoring blocks. A further cable attached to the head of the pipeline transmits directly thereto a part of the haulage force.

Abstract: For laying a submarine pipeline, hauling of the same is exerted by means of a force distribution cable which extends over the full length of the submerged part of the pipeline and which is attached to it by hangers, preferably in conjunction with heavy chains acting as guide ropes and anchoring blocks.

Abstract: The invention consists of a method and apparatus for laying a pipeline, such as an oil duct or a gas duct, in a body of water, wherein the pipeline, or a section thereof, is enclosed within a ballast tube such that an intermediate space is formed between the pipeline or pipeline section and the ballast tube, said space being filled with a liquid less dense than water, such as a light hydrocarbon, while the pipeline is being laid, but may be filled, after the pipeline has been laid, with soft water or with a liquid heavier than water such as a grouting having a base of a hydraulic or hydrocarbon binder. The invention also comprises the provision of a plug at one end of an assembly of pipeline section and ballast tube whereby a free end of said assembly may be secured as by welding to a second assembly of pipeline section and ballast tube at a position remote from the liquid contained in the intermediate space in said first assembly.

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: 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 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.