A spring (5;105;205;305;404;505) for a clamp suitable for attachment to a tubular member, the spring comprising a resilient body (6;106;206;306;406;506) having first and second ends (8;108;208;308;408;508) and an internal surface (7;107;207;307;407;507) adapted to seat within a clamp member and an external surface (9;109;209;309;409;509) adapted to contact the outer surface of a tubular member, the internal and external surfaces extending between the first and second ends and wherein the stiffness of the resilient body of the spring varies over the length of the body between the first and second ends.

A method and apparatus are provided for laying pipelines. The apparatus is attached to a portion of a pipeline and includes a tensioning member and a buoyancy element attached to a mid-portion of the tensioning member. When the buoyancy element is submerged, the buoyancy force tensions the tensioning member, and the pipeline will take the intended deflected shape to follow seabed depressions.

A method and apparatus are provided for laying pipelines. The apparatus is attached to a portion of a pipeline and includes a tensioning member and a buoyancy element attached to a mid-portion of the tensioning member. When the buoyancy element is submerged, the buoyancy force tensions the tensioning member, and the pipeline will take the intended deflected shape to follow seabed depressions.

A system for fluid transfer is disclosed and includes a floatable buoy, an underwater hose, a plurality of underwater node units and circuitry. The underwater hose has a first end coupled to the floatable buoy and a second end. The plurality of underwater node units distributed along the length of the underwater hose and configured to generate positioning signals. The circuitry is configured to determine a relative distance between each of the plurality of undersea node units based on the generated positioning signals to generate a plurality of relative distances.

A system for fluid transfer is disclosed and includes a floatable buoy, an underwater hose, a plurality of underwater node units and circuitry. The underwater hose has a first end coupled to the floatable buoy and a second end. The plurality of underwater node units distributed along the length of the underwater hose and configured to generate positioning signals. The circuitry is configured to determine a relative distance between each of the plurality of undersea node units based on the generated positioning signals to generate a plurality of relative distances.

An apparatus for joining elongated elements in a body of water has a frame; a strap feeding device; two arms movable with respect to the frame and configured to guide a strap around the elongated elements; a clamping device, configured to retain an end portion of the strap; a driving device configured to advance and tighten the strap around the elongated elements; a junction device, configured to join two overlapping portions of the strap so as to close the strap around the elongated elements; and a cutting device configured to separate the strap upstream of the joined portion.

An apparatus for joining elongated elements in a body of water has a frame; a strap feeding device; two arms movable with respect to the frame and configured to guide a strap around the elongated elements; a clamping device, configured to retain an end portion of the strap; a driving device configured to advance and tighten the strap around the elongated elements; a junction device, configured to join two overlapping portions of the strap so as to close the strap around the elongated elements; and a cutting device configured to separate the strap upstream of the joined portion.

A method of dewatering a subsea pipeline bundle assembly before lifting the assembly from the seabed comprises adding discrete buoyancy to an elongate carrier pipe of the assembly. The buoyancy elevates one or more portions of the carrier pipe disposed between drainage outlets of the assembly. Each elevated portion defines inclined falls that slope downwardly in opposed longitudinal directions toward the respective outlets. Water within the carrier pipe drains down the falls toward the outlets. Injecting a dewatering fluid into the carrier pipe promotes expulsion of water from the pipe through the outlets by downward displacement of the water. Drainage can be assisted by a venturi effect driven by accelerating the flow of the dewatering fluid at a location in line with an outlet.

A method of dewatering a subsea pipeline bundle assembly before lifting the assembly from the seabed comprises adding discrete buoyancy to an elongate carrier pipe of the assembly. The buoyancy elevates one or more portions of the carrier pipe disposed between drainage outlets of the assembly. Each elevated portion defines inclined falls that slope downwardly in opposed longitudinal directions toward the respective outlets. Water within the carrier pipe drains down the falls toward the outlets. Injecting a dewatering fluid into the carrier pipe promotes expulsion of water from the pipe through the outlets by downward displacement of the water. Drainage can be assisted by a venturi effect driven by accelerating the flow of the dewatering fluid at a location in line with an outlet.

A subsea riser is installed by lowering at least one riser conduit to the seabed when piggybacked to an elongate support that comprises at least one flowline. The elongate support may be a pipeline bundle, which may be attached to one or more towheads in a towable bundle unit. The riser conduit may be in fluid communication with the flowline. At the seabed, a free end portion of the riser conduit is detached from the elongate support by releasing subsea-releasable fastenings. Then, with the elongate support and a root end of the riser remaining at the seabed, the detached free end portion of the riser conduit is lifted away from the elongate support to a riser support, such as a platform, an FPSO (floating production, storage and offloading vessel), or a buoy.