Abstract: The invention relates to a U-shaped arrangement of floats which are ballastable and deballastable so as to raise and lower their height in the water. On each parallel leg of the float arrangement, are mounted supporting beams that are movable along their longitudinal axes so that they may extend into the center of the U-shaped arrangement of floats and also be retracted therefrom. The device may be used for lifting and transporting large loads by placing the load in the center of the U-shaped arrangement of floats while the floats are ballasted so that they sit low in the water, extending the supporting beams into the center of the arrangement of floats so that they are underneath the load, and then deballasting the floats so that they rise higher in the water while lifting the load.

Abstract: The invention relates to an icebreaker system for marine platforms wherein the system includes two rings of obstacles: a lower ring and an upper ring fixed around pillars of the platform to be protected. The lower ring has obstacles showing a portion sloping upwardly and rearwardly. The upper ring has obstacles staggered with those of the lower ring and showing a portion sloping downwardly and rearwardly. A ring of obstacles is mounted rotatably and/or movably in the vertical direction. The obstacles are of truncated pyramid shape and asymmetrically shaped in front elevation.

Abstract: The device comprises two concentric swivels, a first or mooring swivel being arranged on the outside of the second or bearing swivel, the second swivel being fixed to the end of a cartridge held in a movable manner in a tube forming a projection at the lower end of the shaft and an extension of an axial passage in the shaft. The cartridge is formed by a cage fitted with openings in which keys are housed. A ring is lowered between the keys and immobilizes them against the wall of the tube which forms an extension of the axial passage in the shaft. The method consists of lowering or raising the cartridge carrying the bearing swivel by means of a set of rods.

Abstract: A flexible joint for connection of two pipes comprises a cup-shaped piece which can be connected to a first pipe, a tubular piece which can be connected to a second pipe, the tubular piece being coaxial with the cuplike piece and being arranged partially inside it, and two flexible spherical rings arranged between the cuplike piece and the tubular piece. The two flexible spherical rings are bolted together and arranged on opposite sides of the center of oscillation, the concave surfaces of the rings being directed towards the center of oscillation and being concentric with respect to this center.

Abstract: A mooring assembly connects a submarine conduit to another conduit of a pipe-line or fixed installation. The mooring assembly comprises a mooring frame, a movable mooring arm and a mooring head. The conduit is to be connected to the mooring head having a lateral passage through which the end of the conduit may extend. The movable mooring arm is pivotally mounted on the mooring frame. One end of said other conduit is fixed on the pivot axis of the mooring arm. A connecting pipe connects the end of the submarine conduit to the end of the other conduit. A coupling assembly at the outwardly extending end of the mooring head pivotally connects an axial extension of the end of the conduit to be connected to the mooring head.

Abstract: A concrete structure for the transmission of loads from the steel lattice tower of a marine platform resting on the sea bed by means of concrete base plates, the lattice tower being made up of tubular members which form bracing joints with the legs of the platform. The structure comprises a cylindrical hollow body forming at least part of a platform leg, and having on the inside enclosed spaces defined by internal walls and by the hollow body wall, and concrete fixing plugs formed within the enclosed spaces and engaged by the ends of the lattice members, the enclosed spaces being in the form of hollow rings or vertical shafts within the hollow body.

Abstract: The invention relates to a method for the building and putting in place of a sea platform in using buoyancy chambers. The buoyancy chambers are temporarily attached to the raft and capable of being ballasted for allowing the control of their buoyancy during the building of the structure and their recovery. Simultaneously with the building of the tower and walls, the chambers are progressively built by assembling of portions of bodies mounted on a bottom element resting on a chamber receptacle.

Abstract: A method of welding the ends of submerged pipes in a gaseous atmosphere at any depth comprises isolating the ends of the pipes by introducing obturators therein and then introducing the pipe ends into an open topped receptacle which is capped with an underwater personal carrying intervention unit. The closed receptacle is filled with gas and then a sleeve is positioned between the ends of the pipes and welded to the pipes.

Abstract: A platform resting at the bottom of a body of water, including a plurality of longitudinally disposed bays supported by piers each consisting of a small number of transversely aligned posts resting on a common base and each supporting a cross-beam, each bay comprising a framework of longitudinal beams which rest at either end on the cross-beams, and a method of constructing the platform comprising the steps of preparing each pier onshore, transporting it to the installation site and setting it down on the bottom, raising the base at several points and adjusting their heights above the bottom in order to position the base horizontally, securing the base in that position by pouring concrete beneath it, preparing each bay on the shore, transporting it to the installation site and setting it down on two adjacent piers.

Abstract: A rig which can be towed in floating condition comprises a hollow shaft connected with a base section and supporting a bridge equipped with various installations. In order to allow laying of the base section at a precise location on the seabed, the base section is provided with peripheral notches which can slide along vertical piers and is provided also with piles which are extended and locked when the notches are placed against the piers. Thereafter, the base section is allowed to sink to the bottom by sliding against the piers. Such a rig is useful for oil drilling purposes.

Abstract: An assembly for mooring a submarine conduit to a pipeline or a fixed structure such as a storage tank. The assembly comprises a mooring head, a fixed mooring frame and a movable mooring arm. The mooring head is fixed to the end of the conduit to be connected. The mooring arm is mounted on the fixed mooring frame and is effective to receive the mooring head. The mooring arm is displaceable in a horizontal plane on the mooring frame. An end of the pipeline to which the conduit is to be connected is located on the rotational axis of the mooring arm. A junction pipe connects the end of the conduit to the end of the fixed pipeline. A cable attached to the mooring head passes through the mooring arm and is attached to a winch on the surface for drawing the mooring head into engagement with the mooring arm.

Abstract: In a method of welding together two submerged pipe ends, the pipe ends are spaced apart and introduced through orifices into a receptacle by which they can be isolated from the surrounding medium. The spaced pipe ends are connected by a connection sleeve and after isolation are welded to the connection sleeve.

Abstract: A method of working an underwater deposit comprises the following stages:(a) constructing and positioning a platform structure, equipped before or after positioning with drilling devices and installations,(b) executing drilling using these devices and installations,(c) constructing and equipping, during stages (a) and (b), a production bridge fitted with devices and installations required for production,(d) transporting the production bridge to, and positioning it on, said platform structure, and(e) commencing production from deposit.The drilling bridge may remain in position on the platform structure during stages (d) and (e), or it may be removed to make way for the production bridge.

Abstract: Butt-welding apparatus for welding two pipes, e.g. for the shipboard welding of a laid pipe and a towed pipe, comprises a frame for receiving the pipe ends, means for securing the pipe ends relative to the frame and compensation means for causing movement of one pipe relative to the other to compensate for any shrinkage caused by the welding operation and by preheating the pipe ends to be welded.

Abstract: An assembly for positioning a crane mounted on a support and intended to overhang the platform of a platform structure having a base which rests on the bed of a body of water. The crane is located on the vertical axis of a column offset with respect to a central shaft which carries the platform. The assembly comprises a mobile shaft element contained in the upper part of the offset column and having a base with jacks or a block and tackle permitting its emergence as far as the upper level of the offset column. The lower face of the crane support carries a downwardly extending shaft element which has the same diameter as the mobile shaft element. The two shaft elements are substantially coaxial when the platform is carried on the central shaft so that they may be joined together and raised as a unit.

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: A system for welding the ends of submerged pipes in a gaseous atmosphere at any depth comprises isolating the ends of the pipes by introducing obturators therein and then introducing the pipe ends into an open topped receptacle which is capped with an underwater personal carrying intervention unit. The closed receptacle is filled with gas and then a sleeve is positioned between the ends of the pipes and welded to the pipes.

Abstract: For inspecting and maintaining a submerged installation comprising an emergent part such as a platform, such as an artificial island or a submerged reservoir, said emergent part is equipped with a track along which a trolley associated with a diving bell can be circulated.The track is preferably installed under the platform, above the portions of the infrastructure to be inspected.

Abstract: A method of constructing a hollow column for resting on a base on a submarine bed, comprises the steps of simultaneously starting the construction of a number of elements that are to form the column, causing the partly constructed elements to float, finishing the construction of the elements afloat, bringing the elements into the horizontal position and connecting them together to form the column, said elements being provided with impervious closures at each end thereof and an impervious caisson adjacent each end thereof, and those of the closures and caissons not required when the column is placed in position are dismantled.

Abstract: A footbridge for connection between a fixed installation and an oscillating installation, for example petroleum production platforms, comprising three sections hinged together, the end sections being hinged to rotatable platforms adapted to be secured to the decks of the installations and the platform secured to the oscillating installation being secured thereto by a ball joint. Apparatus is also provided for compensating for the weight of the footbridge, the apparatus consisting of counterweights or jacks mounted on at least one of the installations.