Abstract: Pressure-tight pipeline plugs are used in subsea connection operations to achieve a lightweight pipe condition which facilitates alignment by easing handling problems. An internal plug is provided for this purpose which is particularly useful for connection operations using a pipelay vessel, and which is capable of sealing, remotely releasing and then being pumped out of the line to a terminus.

Abstract: Methods and apparatus are provided for connecting a buoyant off-bottom flowline to a subsea structure.

Abstract: Apparatus for releasably attaching a buoyant module to a submerged pipeline and for releasing the module therefrom is disclosed. The apparatus comprises a strap wrapped over the top of the module and around the underside of the pipeline and a link connected between the opposing ends of the strap. The link is breakable upon application thereto of a design tension greater than that exerted thereon by the positive buoyancy force of the module. The apparatus also comprises a sled slideably mounted on the upper surface of the pipeline, means for engaging the sled to a source of propulsion and a wedge attached to the leading end of the sled which has an inclined surface sloping downwardly from the top of the sled to the pipeline and pryably engageable with the module.

Abstract: A pressure-actuated release mechanism is assembled using a prebuckled pipe segment as a pressure-triggering mechanism. The trigger mechanism is employed to attach buoys to an offshore structure or pipeline under construction. The attached buoys move with the structure or newly added pipe string toward the sea bottom, easing the descent. As a preselected external pressure is sensed, the buckle in the pipe segment propagates and the trigger mechanism actuates, releasing buoys from the structure or pipeline as each buoy in turn reaches the same depth or pressure.

Abstract: Pipe adapted to be installed underwater at increased ocean depths by practical pipe-laying procedures comprises a porous cement shell filled with hollow spheres that are slowly permeable to water under pressure. The cement shell is filled with a sufficient volume of the hollow spheres to make the pipe only slightly heavier than sea water, providing a reduced weight that overcomes previous difficulties in laying pipe at great depths. Over a period of time after the pipe has been installed underwater, the hollow spheres gradually fill with water and make the pipe rest stably on the ocean bottom. The preferred spheres comprise porous core spheres coated with thin coatings that partially seal the spheres to the needed degree of permeability.

Abstract: A primary supporting truss comprising a surface float supporting an anchor within a fluid medium, a subsurface float connected to the anchor and a weight connected to the subsurface float and the anchor is deployed by a drogue by engaging currents within the fluid medium. The drogue is connected to the subsurface float and devices are suspended between the anchor and the subsurface float in a horizontal position. Alternatively, the drogue may be connected to the weight and the devices may be suspended between the anchor and the weight. The apparatus may include a plurality of secondary supporting trusses, each comprising a subsurface float and a weight connected between the primary supporting truss and the drogue for supporting additional devices.

Abstract: A gel plug of vegetable oil, fatty acid, a particulate filler such as calcium carbonate, and an optional base and/or polymer is employed during construction of an offshore pipeline to separate a gas-filled portion of the pipeline from a water-flooded portion, and to facilitate control and movement of a gas/gel plug/water interface as desired to assist in construction operations.

Abstract: A gel plug of mineral oil, organo-modified smectite, and a particulate filler such as powdered coal, or a gel plug of mineral oil and organo-modified smectite is employed during construction of an off-shore pipeline to separate a gas-filled portion of the pipeline from a water-flooded portion, and to facilitate control and movement of a gas/gel plug/water interface as desired to assist in construction operations.

Abstract: A flow line bundle assembly includes a plurality of conduits disposed within a tubular covering member. The tubular covering member is sealed at its ends before being placed in a body of water, so that the flow line bundle has a slight positive buoyancy when submerged in the body of water. Weights are then added to the flow line bundle to cause it to have a neutral buoyancy at a position slightly above a floor of the body of water. The flow line bundle is then towed from its point of construction, through the body of water, to the location where it is to be installed. During a first method of towing, if an obstacle located above the ocean floor is approached, a trailing tug increases a restraining force applied to the flow line bundle so as to lift it above the obstacle as the flow line bundle passes over the obstacle. A second method of towing maintains the flow line bundle at a constant depth below a surface of the body of water so that the bundle will clear any obstacles on the floor of the body of water.

Abstract: A flow line bundle assembly includes a plurality of conduits disposed within a tubular covering member. The tubular covering member is sealed at its ends before being placed in a body of water, so that the flow line bundle has a slight positive buoyancy when submerged in the body of water. Weights are then added to the flow line bundle to cause it to have a neutral buoyancy at a position slightly above a floor of the body of water. The flow line bundle is then towed from its point of construction, through the body of water, to the location where it is to be installed. During a first method of towing, if an obstacle located above the ocean floor is approached, a trailing tug increases a restraining force applied to the flow line bundle so as to lift it above the obstacle as the flow line bundle passes over the obstacle. A second method of towing maintains the flow line bundle at a constant depth below a surface of the body of water so that the bundle will clear any obstacles on the floor of the body of water.

Abstract: Method and apparatus for recovering a length of an electric cable from great depths of water in which a first device with a buoyancy tank and cable gripping jaws is lowered into the water and guided into position over the cable by an operator controlled submarine having manipulating arms. The tank is then released from the remaining equipment and rises to the water surface letting out a rope secured at its lower end to the remaining equipment. The operator then operates the jaws into gripping engagement with the cable. Thereafter, the rope is secured to a tensioning line on a surface ship, and a second device is lowered by the ship along the rope so as to settle in the remaining equipment, the latter being formed to fit into and with a cage at the bottom of the second device. The second device has a plurality of articulated clamping jaws which the operator operates into gripping engagement with the cable, and by raising the second device from the ship, a length of the cable is brought to the water surface.

Abstract: Method and apparatus for laying an underwater pipe to straddle an already laid pipe, comprising fastening to the pipe to be laid, at appropriate distances apart, a set of trestles the heights of which are gradually increasing and decreasing consistent with the bend to be imparted to the pipe to be laid in order to have it positioned in the correct straddling relationship relative to the already laid pipe. Each trestle is connected to the pipe to be laid by flexible means which allow the trestle to move vertically, longitudinally and traversely relative to the pipe and to be suspended below and separate from the pipe as the pipe and trestle descend to the sea bed for proper positioning of the trestle substantially independent of the pipe.

Abstract: A system for installing one or more side-by-side submerged pipelines from the shore while preventing abrasive contact between the pipe and any of the ground, the seabed or the equipment used. The line is assembled from joints on shore, clamped between timbers at spaced intervals, hauled down a track supported by the timbers to the water's edge where buoyant spherical wheels are detachably secured to the clamping timbers. The pipeline is pulled into the water, rolling on the wheels which maintain it in spaced relation to the seabed and which when the pipeline reaches its final destination, are released to float to the surface for retrieval. Additional lengths of pipe may be added periodically on the shore so that pipelines of any desired length can be installed. The wheel assemblies are released by pulling buoyed trip lines whose buoys floating on the surface mark the path of travel of the pipeline as it is pulled along the seabed.

Abstract: A buoyant pipe system designed for underwater use of pipe conduits with equalized inside and outside pipe conduit pressures when transporting liquid, the conduits being thin-walled with external water inlet means, and being capped by a floatation chamber, the pipe system having a series of spaced anchor assemblies including an anchor member and a cable connector for anchoring the pipe conduit in an underwater floating condition.

Abstract: A method is disclosed for repairing a damaged pipe laid on deep sea beds, said method substantially comprising the step of joining a central pipe stub between the ends of the two adjoining pipe portions, such operation being performed directly on the sea bed rather than on the pipe-laying barge. Special coupling sleeves are provided at both ends of the central pipe stub, said sleeves being received in a watertight manner on the two pipe terminal portions, by clamping said sleeves thereon. Apparatus and tools for carrying out said method are described in great detail.

Abstract: Connecting means for connecting the ends of at least a pair of pipes, said pipe ends being immersed in water and one of the or each pair of pipe ends being mounted on a fixed structure and connected, e.g. to an oil well, and the other of the or each pair of pipes being mounted on a movable structure, e.g. a column, mounted for oscillatory movement relative to the fixed structure, comprises in respect of the or each pair of pipes a tube of a length greater than the maximum distance between the pipe ends and in a spiral and/or helical shape, wherein the tube is supported intermediate the ends thereof solely by means for correcting the buoyancy thereof to reduce the buoyancy to substantially zero.

Abstract: The equipment is connected through a line to an auxiliary buoyant element to form an assembly of positive buoyancy, the equipment to be submerged and the auxiliary element being at first held in spaced relationship. The equipment is thereafter dropped into water, the length of the connecting line being so limited that the equipment then becomes suspended in water under the auxiliary element without reaching the water bottom. The location of the assembly is then optionally adjusted, and its buoyancy is reduced to a negative value.

Abstract: This device comprises a pipe formed of separate flexible pipe sections which in use are supported by buoyant elements maintained immersed by anchoring means. The flexible pipe sections are interconnected by couplings with at least some of these couplings being connected to a buoyant element and comprising stress limiters applied to the pipe sections adjacent said couplings.

Abstract: Apparatus and method for laying a pipeline on the bottom of an ocean wherein a wheel-like, buoyant body is adapted to carry a single, continuous length of pipe in the form of horizontal convolutions from a first site at which the pipe is wrapped on the body to a second site where the convolutions are moved into vertical positions and the pipe is unwrapped from the body and allowed to gravitate toward and to be laid on the bottom of the ocean. The pipe is wrapped on the body when the latter is horizontally disposed and floating on the water near a dock, and the wrapping can be accomplished whether the elastic bending limit of the pipe is exceeded or not. The body with the convolutions of pipe are towed to the second site while the body and the pipe remains horizontally disposed. Then a tank forming part of the body receives sea water to unbalance the body and cause it to be moved into a vertical position.

Abstract: An apparatus for imparting suitable buoyancy to submerged articles, such as pipelines, to reduce their weight in water and enable efficient movement thereof. The apparatus comprises at least one float comprising air tight material, pipe for supplying pressurized air thereinto, and a differential pressure regulating valve arranged close to the float and connectable to the pipe for regulating the amount of pressurized air supplied to the float dependent upon the difference in pressure between that in the float and a predetermined value. Advantageously, the apparatus is easily transportable, stored and attached to the items to which it imparts the desired amount of buoyancy; the apparatus also keeps constant the buoyancy regardless of the depth of water, thus, enabling easy and safe moving of submerged articles.

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 method and system for connecting the ends of a pair of tubular conduits for use at the bottom of a body of water in which terminal portions of said conduits, adjacent to and including said ends, are buoyantly supported in a generally elevated attitude within the body of water with the ends in a zone of the body of water below the surface thereof. The ends are positively fixed against movement relative to each other but permitted limited movement, as a unit, relative to the bottom of the body of water. The connection of the conduit ends is made within the aforementioned zone of the body of water.

Abstract: A method for the controlled bending of a submerged pipeline is disclosed. The section of the pipeline which is to be bent is slightly elevated off the sea floor, preferably by buoys attached to the pipeline along its length. The end of the elevated section of pipeline is pulled in to the desired point of termination while a drag force is simultaneously applied to the elevated portion of the pipeline. The applied drag force should be sufficient to create a bending moment which causes the pipeline to bend along a well defined arc. Preferably, dragging means such as chains, cables, or clump weights extending from the pipeline to the sea floor are used to impose the necessary drag force on the pipeline and to control elevation of the pipeline above the sea floor.

Abstract: A device for positioning a pipeline intended to rest on the bottom of the sea or of a body of water. In order to present a resistance to the drifting of the pipeline by the action of cross-currents, the pipeline is provided with a plurality of support members suitably distributed along the pipeline and extending in a direction generally parallel to the vertical plane containing the longitudinal axis of the pipeline. The support members project below the pipeline towards the bottom and are deformable in the vertical plane by the reaction of the bottom on the support members, but are transversely rigid.

Abstract: For laying a pipeline on the sea bed to interconnect first and second spaced underwater installations, a pipeline section is towed from the first to the second installation, the front and rear ends being maintained above the sea bed 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 two end portions of the pipeline are inserted into the respective installations, and the floats eventually ballasted or liberated.

Abstract: Method of assembling and laying at least one fluid conveying conduit between an on-shore point and an advanced off-shore point, including erecting, regularly on the bottom of the sea, partially emersed pillars, prefabricating conduit sections before or after erecting the pillars, mounting said sections between and at least partially supporting the same on the successive pillars and interconnecting these sections. Where there are at least three conduits, they may be provided in a bunch arrangement and suspended between the pillars. Where the conduits are partially immersed, they are provided with a rising branch at each end to be connected one to another above the level of the sea.

Abstract: An improved thermally active submarine conductor for transmission of high voltage electrical power within bodies of water whose maximum depth and pressure is in excess of the maximum depth and pressure operative capacity of available conductive elements of the said conductor, as well as alternative means for the said transmission. The said conductor is comprised of a number of specifically adapted interdependent elements, each essential to the said transmission function, including: thermally active conduction and insulation elements, and sheathing and mechanical armorment elements as may be required for depth pressure and mechanical flexing protection, in addition to flotation elements, and tethering and anchoring stabilization elements, in order to maintain the said conductive elements at a functional depth and lateral routing, within a prescribed variance range radially circumscribing the said routing; and to prevent said elements from descending to a depth and pressure prohibitive to their proper function.

Abstract: A new and improved apparatus for installing marine pipelines in a body of water and the method of using the same including multiple support units having buoyancy tanks and roller-tensioner means for operatively securing the support units to the pipeline submerged in the water at spaced intervals along the pipeline to control the pipeline configuration between a laying vessel and the bottom of the body of water. The support units include control means which is preset or has a remote controller operable from the laying vessel to adjust the buoyancy of the buoyancy tanks and the tension on the tensioner means to control the position of the support units on the pipeline and the amount of lifting force to the pipeline.

Abstract: An installation for the release of floats supporting by individual cables a structure submerged in an aqueous medium, comprising attachment means fixed on the structure and co-operating with one end of said cable, the other end carrying the float, liberating means co-operating with said attachment means, and a control station for said liberating means, wherein the first of said liberating means is connected to a principal control line connected to the control station, the subsequent liberating means being connected together in such manner that they are automatically and successively actuated after said first liberating means has been actuated via the principal control line, the principal control line and the connections between successive liberating means consisting of fluid pressure lines or electric cables.

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: Process and equipment for laying on the ocean floor a pipeline for the transfer of liquids or gas. In this process, the pipeline is constructed in a staging or shallow water area where the pipe is equipped with separate buoyancy and handling means, the conduit is submerged, towed to a location vertically above the pipeline route, the conduit is raised to the surface for inspection and preparation, one resumes in a controlled fashion and completes the submersion and positioning on the ocean floor, and finally the buoyancy and handling means are recovered. This process, due to its use of buoyancy and handling devices, considerably lowers the installation cost of underwater pipelines.

Abstract: A system of submarine cranes suited to handling pipe, fittings, tools and machinery on the marine floor, as by divers, and having simple articulate carrying crossbeams with hydraulic motive means and controls, and possible balloon assistance and means to hump and bend, couple, and repair pipelines and machines under water.