Abstract: A mooring system for offshore vessels uses a chain stopper within a preset mooring line. The chain stopper has means for attaching a removable hydraulic chain jack actuator which may be used to stroke the chain through the stopper assembly while both the stopper and the mooring line remain under load.

Abstract: A disconnectable buoyant turret mooring system for an FPSO is vulnerable to damage from collisions between the buoy and the buoy turret cage during mating and de-mating operations. It is therefore desirable that the buoy separate quickly from the turret of the FPSO vessel during a disconnect operation. A buoy turret cage is provided with a certain degree of porosity that allows a flow of seawater from the outside of the receptor to the inner surface of the receptor. Introducing water in this way relieves the suction forces and allows for a quicker separation of the buoy from the turret of the FPSO vessel, minimizing the time during which an uncontrolled collision between the buoy and the FPSO vessel is most likely. Filling a portion of the turret above the mooring buoy with water prior to releasing the buoy also decreases the separation time.

Abstract: A disconnectable buoyant turret mooring system for an FPSO is vulnerable to damage from collisions between the buoy and the buoy turret cage during mating and de-mating operations. It is therefore desirable that the buoy separate quickly from the turret of the FPSO vessel during a disconnect operation. A buoy turret cage is provided with a certain degree of porosity that allows a flow of seawater from the outside of the receptor to the inner surface of the receptor. Introducing water in this way relieves the suction forces and allows for a quicker separation of the buoy from the turret of the FPSO vessel, minimizing the time during which an uncontrolled collision between the buoy and the FPSO vessel is most likely. Filling a portion of the turret above the mooring buoy with water prior to releasing the buoy also decreases the separation time.

Abstract: A mooring system for offshore vessels uses a chain stopper within a preset mooring line. The chain stopper has means for attaching a removable hydraulic chain jack actuator which may be used to stroke the chain through the stopper assembly while both the stopper and the mooring line remain under load.

Abstract: A mooring system for offshore vessels uses a chain stopper within a preset mooring line. The chain stopper has means for attaching a removable hydraulic chain jack actuator which may be used to stroke the chain through the stopper assembly while both the stopper and the mooring line remain under load.

Abstract: A hull, suitable for use as a tension leg platform (TLP) or as a semi-submersible vessel, comprises columns having a generally polygonal transverse cross section at least one axis of which is generally radially aligned with the central vertical axis of the hull. Buoyant, subsurface pontoons interconnect adjacent columns. The pontoons are generally rectangular in cross section and the outboard, generally vertical surface of each pontoon is connected to a side surface of an adjoining column at a location which is substantially inboard of the outermost face of the column. In certain embodiments of the invention, tendon porches (configured to receive the upper tendon connectors of a TLP) are mounted to the outboard surface of one or more pontoons.

Abstract: A hull, suitable for use as a tension leg platform (TLP) or as a semi-submersible vessel, comprises four columns arranged in a rectangular planform with each column having a generally polygonal transverse cross section at least one axis of which is generally disposed at a 45-degree angle to a line between the center points of adjacent columns. Buoyant, subsurface pontoons interconnect adjacent columns. The pontoons are generally rectangular in cross section and the outboard, generally vertical surface of each pontoon is connected to a side surface of an adjoining column at a location which is substantially inboard of the outermost face of the column. In certain embodiments of the invention, tendon porches (configured to receive the upper tendon connectors of a TLP) are mounted to the outboard surface of one or more pontoons.

Abstract: A tendon is assembled in a horizontal orientation using connectors or by welding at a weld station on a barge or other vessel located at or near the installation site of a tension leg platform. During assembly, the tendon is pulled away from the assembly vessel and tensioned by a tug or offshore work vessel. When fully assembled, the tendon may be up-ended in a manner similar to a wet-towed tendon, and then either pre-installed using floats or passed over to a TLP which is on-site and ready to receive tendons.

Abstract: Flexible hang-off arrangement is provided for a catenary riser suspended from an offshore or inshore platform, which includes floating or fixed platforms, vessels or/and buoys. The bending loads in the top segments of the said riser are reduced by incorporating a pivot at the riser hang-off. Pressure containing welded, bolted, rolled or swaged pipe spools transfer fluids, including hydrocarbons between the riser and the platform. Along significant spool lengths the tangents to the center lines of said spools are orthogonal to and offset from the tangent to the center line of the riser at the hang-off. The said pressure containing spools include arbitrary looped, spiral and helicoidal designs that are subject to torsion.

Abstract: A tendon is assembled in a horizontal orientation using connectors or by welding at a weld station on a barge or other vessel located at or near the installation site of a tension leg platform. During assembly, the tendon is pulled away from the assembly vessel and tensioned by a tug or offshore work vessel. When fully assembled, the tendon may be up-ended in a manner similar to a wet-towed tendon, and then either pre-installed using floats or passed over to a TLP which is on-site and ready to receive tendons.

Abstract: A mooring system for offshore vessels uses a chain stopper within a preset mooring line. The chain stopper has means for attaching a removable hydraulic chain jack actuator which may be used to stroke the chain through the stopper assembly while both the stopper and the mooring line remain under load.

Abstract: A tendon is assembled in a horizontal orientation using connectors or by welding at a weld station on a barge or other vessel located at or near the installation site of a tension leg platform. During assembly, the tendon is pulled away from the assembly vessel and tensioned by a tug or offshore work vessel. When fully assembled, the tendon may be up-ended in a manner similar to a wet-towed tendon, and then either pre-installed using floats or passed over to a TLP which is on-site and ready to receive tendons.

Abstract: Flexible hang-off arrangement is provided for a catenary riser suspended from an offshore or inshore platform, which includes floating or fixed platforms, vessels or/and buoys. The bending loads in the top segments of the said riser are reduced by incorporating a pivot at the riser hang-off. Pressure containing welded, bolted, rolled or swaged pipe spools transfer fluids, including hydrocarbons between the riser and the platform. Along significant spool lengths the tangents to the center lines of said spools are orthogonal to and offset from the tangent to the center line of the riser at the hang-off. The said pressure containing spools include arbitrary looped, spiral and helicoidal designs that are subject to torsion.

Abstract: A floating vessel is equipped with perforated plates which exhibit both an added-mass effect and a damping effect. The addition of porosity to an added mass plate phase-shifts the added mass force so that it becomes at least partially a damping force which does not depend on large velocities to develop a large damping force. Preferred porosity is in the range of about 5% to about 15% of total plate area. A semi-submersible vessel may have damper plates fitted between its surface-piercing columns, within a support grid in the area between the pontoons and/or extending from the sides of its pontoons. A truss spar offshore platform may have damper plates installed within its truss structure intermediate its hull and ballast tank. Drill ships and similar vessels may be equipped with damper plates extending from the sides of their hulls to reduce both heave and roll.

Abstract: A hull, suitable for use as a tension leg platform (TLP) or as a semi-submersible vessel, comprises four columns arranged in a rectangular planform with each column having a generally polygonal transverse cross section at least one axis of which is generally disposed at a 45-degree angle to a line between the center points of adjacent columns. Buoyant, subsurface pontoons interconnect adjacent columns. The pontoons are generally rectangular in cross section and the outboard, generally vertical surface of each pontoon is connected to a side surface of an adjoining column at a location which is substantially inboard of the outermost face of the column. In certain embodiments of the invention, tendon porches (configured to receive the upper tendon connectors of a TLP) are mounted to the outboard surface of one or more pontoons.

Abstract: A hull, suitable for use as a tension leg platform (TLP) or as a semi-submersible vessel, comprises columns having a generally polygonal transverse cross section at least one axis of which is generally radially aligned with the central vertical axis of the hull. Buoyant, subsurface pontoons interconnect adjacent columns. The pontoons are generally rectangular in cross section and the outboard, generally vertical surface of each pontoon is connected to a side surface of an adjoining column at a location which is substantially inboard of the outermost face of the column. In certain embodiments of the invention, tendon porches (configured to receive the upper tendon connectors of a TLP) are mounted to the outboard surface of one or more pontoons.

Abstract: A floating vessel is equipped with perforated plates which exhibit both an added-mass effect and a damping effect. The addition of porosity to an added mass plate phase-shifts the added mass force so that it becomes at least partially a damping force which does not depend on large velocities to develop a large damping force. Preferred porosity is in the range of about 5% to about 15% of total plate area. A semi-submersible drilling rig may have damper plates fitted between its surface-piercing columns and/or extending from the sides of its pontoons. A truss spar offshore platform may have damper plates installed within its truss structure intermediate its hull and ballast tank. Drill ships and similar vessels may be equipped with damper plates extending from the sides of their hulls to reduce both heave and roll. In certain embodiments, the damper plates are retractable so as not to interfere with docking and to reduce drag while the vessel is underway.

Abstract: A tendon is assembled in a horizontal orientation using connectors or by welding at a weld station on a barge or other vessel located at or near the installation site of a tension leg platform. During assembly, the tendon is pulled away from the assembly vessel and tensioned by a tug or offshore work vessel. When fully assembled, the tendon may be up-ended in a manner similar to a wet-towed tendon, and then either pre-installed using floats or passed over to a TLP which is on-site and ready to receive tendons.

Abstract: A floating vessel is equipped with perforated plates which exhibit both an added-mass effect and a damping effect. The addition of porosity to an added mass plate phase-shifts the added mass force so that it becomes at least partially a damping force which does not depend on large velocities to develop a large damping force. Preferred porosity is in the range of about 5% to about 15% of total plate area. A semi-submersible vessel may have damper plates fitted between its surface-piercing columns, within a support grid in the area between the pontoons and/or extending from the sides of its pontoons. A truss spar offshore platform may have damper plates installed within its truss structure intermediate its hull and ballast tank. Drill ships and similar vessels may be equipped with damper plates extending from the sides of their hulls to reduce both heave and roll.

Abstract: A floating vessel is equipped with perforated plates which exhibit both an added-mass effect and a damping effect. The addition of porosity to an added mass plate phase-shifts the added mass force so that it becomes at least partially a damping force which does not depend on large velocities to develop a large damping force. Preferred porosity is in the range of about 5% to about 15% of total plate area. A semi-submersible drilling rig may have damper plates fitted between its surface-piercing columns and/or extending from the sides of its pontoons. A truss spar offshore platform may have damper plates installed within its truss structure intermediate its hull and ballast tank. Drill ships and similar vessels may be equipped with damper plates extending from the sides of their hulls to reduce both heave and roll. In certain embodiments, the damper plates are retractable so as not to interfere with docking and to reduce drag while the vessel is underway.