Abstract: A method and apparatus for entrenching an elongated pipeline and the like uses a trenching apparatus having a trench cutting assembly which is detachably connected to a sled base. A floating vessel has means to control positioning of the trenching apparatus, including means to raise and lower, and to connect and disconnect, the trench cutting assembly and the sled base. Several methods and apparatus are disclosed for raising and lowering the trench cutting assembly while leaving the sled base positioned on the bottom of the body of water, straddling the elongated pipeline. In each embodiment, the cutting means may be lifted on board the vessel for maintenance and/or repair, leaving the sled base in position relative to the pipeline. Means are provided for abandoning the sled base at the entrenching site and returning later to lower the trench cutting assembly into its operational relationship with the sled base.

Abstract: An offshore pipeline installation comprises a wellhead base and a pipeline anchor connected together to form a unit which is lowered onto a seabed. The anchor is pivotably positionable relative to the wellhead base about a vertical axis of a pilot tube. A pin pile is inserted through the tube and into the seabed to isolate the pipeline anchor from the wellhead and wellhead base in relation to forces generated in anchoring a pipeline to the pipeline anchor. The anchor is selectively positionable for alignment with pipeline means to be laid, and may include a socket mounted for pivotal movement about one or more, axis. The socket is operable to receive pipeline means laid away from the anchor. The anchor may further include a ramp which is inclined relative to horizontal. The ramp is positionable generally laterally relative to the lay path of the pipeline means so that pipeline means laid upon the ramp gravitates downwardly toward clamp means at the foot of the ramp.

Abstract: The invention relates to methods and apparatus for effecting deep water repair of pipelines especially during a pipelaying operation. A damaged portion of the pipeline is located and is prepared for receiving a pipeline plug member by cutting away the damaged portion leaving a prepared pipeline end section. The pipeline plug member is secured in a submersible repair frame which is lowered from a floating vessel into an operational relationship with the prepared pipeline end section. The plug member is aligned with the pipeline end section and is inserted into the end section. Thereafter, the plug member is sealingly secured in the pipeline end section and the repair frame is removed from its operational relationship with the pipeline. The pipeline is dewatered and the end section is then raised onto a floating vessel.

Abstract: An underwater storage assembly comprising a plurality of tanks secured on a skid is described. The tanks are each divided into two compartments by flexible membranes secured to the inner walls of the tanks. One compartment has an open passage to the surrounding seawater while the second compartment is fluid-tight and expands as a fluid, petroleum, is pumped into it. The tanks are elevated at one end to enable fluid to be stored and discharged more easily.

Abstract: Method for transporting an offshore tower to a desired deepwater site and for erecting the tower to an upright position on the submarine floor at that site. Initially, the intended base end of the tower is supported on a first barge, and the intended top end is supported on a second barge. The barges are then towed to the deepwater site. At the site, the tower is launched by first mutually separating the barges through the application of substantially horizontal and oppositely directed forces, while maintaining one tower end substantially stationary with respect to its supporting barge, and permitting the other tower end to slide off of the other barge. Therefor, the other tower end is moved off of the other barge.

Abstract: The invention relates to a device for removing material from a submerged surface. The apparatus has a liquid manifold which supports downwardly directed liquid jets to dig or remove material and upwardly directed liquid jets to impel the removed material into the interior of a material removing housing and a gas manifold having a plurality of air jets to help urge the material into and through the material removing housing. Means are provided for dividing the liquid and gas manifolds into zones and for directing all of the supplied liquid and gas to one or more zones of the respective manifolds to either intensify and localize the effect of the fluids or to maintain the device in an operable condition when the source of gas and/or liquid is partially impaired.

Abstract: An improved articulated stinger for laying pipe at the bottom of a body of water is disclosed. The first structural support for the pipe, after it leaves the vessel, is provided at a substantial distance from the vessel. A long, nonarticulated stinger link, attached to the vessel, does not engage the pipe and serves to position a buoyant stinger means beneath an effective wave action water depth. In addition, the long length of the stinger link separates the buoyant stinger means (and first pipeline support) from the vessel by a distance sufficient to substantially decouple vessel motion from the buoyant stinger means. There results through this arrangement significantly less banging between the pipe and the stinger assembly.

Abstract: An offshore oil or gas recovery station is established by docking a jacket with a submerged wellhead and supporting a platform on the jacket above the water surface. The jacket is lowered upon the wellhead so that a guide collar on the jacket passes downwardly around the wellhead. Alignment pins on the guide collar are fully advanced by a diver so as to contact the wellhead and effect alignment between the wellhead and a conduit which is carried on the jacket by a temporary connection. The conduit is released and is lowered onto the wellhead for connection therewith.

Abstract: A novel guide member and guide member support arrangement for guiding a drill conductor from a deck portion of an offshore platform into the bottom of a body of water is disclosed. The guide member is snugly nestled against and positioned within the guide member support which directly provides lateral and vertical support for the guide member. The guide member has an upper funnel-shaped portion and a lower cylindrical portion. The guide member support comprises the plurality of connected structural members arranged in a plane for defining a support opening for the guide member. The guide member is connected to the guide member support at at least three positions.

Abstract: A guide member having the advantage of the "J-tube" and "bending shoe" risers, for installing a riser pipeline between a submerged pipeline and an above water facility of an offshore apparatus, is disclosed. The guide member has a J-shape and has three sections: a long, tubular, vertically extending upper section, a short, tubular, substantially horizontal lead-in section, and a curved channel section extending between the upper and lead-in sections. The curved channel section is open on a side away from the lead-in section. The resulting guide member requires a substantially smaller pulling force than would be required with a comparable J-tube riser and avoids the manipulative complications of conventional "bending shoe" risers.

Abstract: A tower is installed at an offshore worksite by floating to the worksite a tower subassembly which comprises a base, a plurality of upright open-trussed initial leg segments, and a plurality of flotation tanks. A plurality of open-trussed add-on leg segments are stored on a vessel in the vicinity of the worksite. The flotation tanks are ballasted to partially immerse the subassembly so that buoyant jacking units disposed within and connected to respective ones of the initial leg segments floatingly support the subassembly, with top portions of the initial leg segments projecting above the water surface. Add-on leg segments are mounted onto the leg portions projecting above the water surface. While the subassembly is suspended from the jacking units, the subassembly is lowered so that the jacking units enter the add-on leg segments as the add-on leg segments pass downwardly therearound. These steps are repeated so that the subassembly is gradually built-up with leg segments and is progressively submerged.

Abstract: A jacket for use in supporting an offshore platform. The jacket is of the type having a plurality of legs interconnected by a plurality of bracing members, a number of the bracing members having means for connection with the cables of apparatus for lifting the jacket during transportation and positioning thereof. The jacket has improved connection means comprising a plurality of self-aligning, reusable padeyes and a corresponding plurality of padeye mounting sites. Each mounting site comprises a cylindrical padeye receiving portion comprising a section of a bracing member, and is bounded axially by stop means. Each padeye comprises a pair of hinged, generally hemispherical clamp members which, when closed, form a cylindrical hollow sized to fit the receiving portion. An eyelet is rigidly mounted on each clamp member and defines a hole for receiving a pin and a stop surface.

Abstract: Improvements in buoyancy structures independently comprising each ofA radiating, circumferentially extending buoyancy cell network encircling an offshore jacket leg, andA double-walled buoyancy chamber wall fabricated from a shell and overlapping pipe segments bonded thereto.An offshore platform jacket assembly is disclosed in which a plurality of jacket legs are anchored by piling members to the bed of a body of water. A buoyancy unit is disposed at a lower portion of the jacket in association with at least one of the jaket legs. Each buoyancy unit comprises a chamber disposed around its respective leg. Each chamber is divided into a plurality of circumferentially displaced, radiating cells and these cells are disposed inwardly of a periphery defined by a series of piling guides spaced around the leg. A plurality of generally upright divider fins extend radially outwardly from the leg to divide the chamber into the radiating cells which are arranged about the leg for the reception of a buoyant medium.

Abstract: A method of installing a riser to provide a continuous flow path from a relatively rigid pipeline lying on the bottom of a body of water to an above water connection on an offshore apparatus is disclosed. The riser according to one aspect of the invention is a tubular flexible conduit and in a second aspect is a rigid member connected to the pipeline by a flexible section. The method of the invention for installing the riser uses available equipment, relatively small lifting forces and avoids the deformation of rigid pipe. In one particular embodiment, the pipeline-riser combination is laid on the bottom of the body of water and according to the method, the riser member is thereafter raised to a vertical orientation with respect to the offshore platform. The method provides a riser which does not undergo deformation at the bending zone wherein fluid flow changes between the horizontal and vertical directions.

Abstract: Disclosed are a method and apparatus for laying a submergible elongate structure upon the bed of a body of water. The last-assembled portion of the structure is supported upon a floating vessel having a deck which defines a path for movement of the structure relative to the deck, the path including an assembly region in which additional submergible elongate structure can be assembled from components. The structure is clamped downstream (relative to the path of movement) of the assembly region and then additional submergible elongate structure is assembled in that region and is secured to the previously existing structure. The free end of the additional structure is gripped with a connector that is connected, through a flexible cable under tension, to a winch. Then the clamping assembly is disengaged from the structure so that the winch alone maintains tension on the structure.

Abstract: Disclosed is an apparatus for cushioning and absorbing force between relatively moving bodies and for dissipating the impact energy, preferably in a marine environment. The apparatus is securable to a structure in a marine environment and typically cushions the impact between a marine means (i.e., barge, boat, etc.) and that structure. The apparatus comprises an upright frame, laterally spaced apart upper shock mounts securing the frame to the structure. Each of the shock mounts includes a shear-type, shock-absorbing, resiliently-deformable member disposed intermediate the upright frame and the structure to which it is secured. The resiliently-deformable members of the upper shock mounts are disposed in an orientation in which they provide both compressive and shear resistance to horizontal loading on the frame.

Abstract: An elongated deck section having two rows of legs with several legs per row is fabricated with the legs hingedly mounted on footings adapted to receive fluid bearings and is transported from the fabricating yard to a dock head over a smooth concrete slab of minimal slope and thence longitudinally via fluid bearing adapted gang planks and tracks onto and along a barge disposed with its stern adjacent the dock head and grounded thereat, the platform being transported by placing fluid bearings under the footings which allow the section to be moved sideways, lengthways, or rotated or turned, as desired, the deck's horizontal truss stresses and the fluid bearing loads being controlled by actuating fluid elevators between each leg and the fluid bearing thereunder, the barge being initially ballasted so that change of ballast during loading is unnecessary to maintain minimal slope of the barge, the section then being anchored to the barge and the barge reballasted to float its stern and trim the barge preparatory to

Abstract: A shoe for adjustably supporting a pipeline relative to a ramp of a lay vessel is comprised of a cradle which supports the pipeline in longitudinally movable relation with the ramp. The cradle contacts the pipeline intermediate the longitudinal axis of the pipeline and the surface of the ramp. An elongated lever is pivotally connected at one extreme to the ramp and at another extreme to the cradle. The elongated lever is rotated by rotating means about the pivotal connection with the surface of the ramp to alternately raise and lower the cradle and thereby adjustably support the pipeline relative to the ramp.According to the method of the invention, a pipeline can be adjustably supported relative to a ramp of a lay vessel by first cradling the pipeline above the surface of the ramp in longitudinally movable relation therewith. This step may be accomplished by a cradle having two degrees of freedom relative to the ramp and pivotally connected thereto through an elongated lever.

Abstract: A method and apparatus for connecting and disconnecting a buoyant structure and tower jacket characterized by mutually telescope portions of mated stanchions extending between the buoyant structure and tower jacket, which telescopingly mated stanchion portions are mutually secured by clamping means guidingly carried by the buoyant structure.

Abstract: Improvements in buoyancy structures independently comprising each ofA radiating, circumferentially extending buoyancy cell network encircling an offshore jacket leg, andA double-walled buoyancy chamber wall fabricated from a shell and overlapping pipe segments bonded thereto.An offshore platform jacket assembly is disclosed in which a plurality of jacket legs are anchored by piling members to the bed of a body of water. A buoyancy unit is disposed at a lower portion of the jacket in association with at least one of the jacket legs. Each buoyancy unit comprises a chamber disposed around its respective leg. Each chamber is divided into a plurality of circumferentially displaced, radiating cells and these cells are disposed inwardly of a periphery defined by a series of piling guides spaced around the leg. A plurality of generally upright divider fins extend radially outwardly from the leg to divide the chamber into the radiating cells which are arranged about the leg for the reception of a buoyant medium.