Pulling structures into water
AssigneeSubsea 7 Limited
InventorsArnbjorn Joensen, Nwabueze Samuel Ogbodo
Life of this patent
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Abstract
A structure such as a pipeline bundle is pulled into or through shallow water, for example, when launching the structure, by applying a tensile pulling force to the structure through rigging that extends to the structure from a winch of a first vessel. The pulling force is at least partially reacted through a pennant line that extends from the first vessel to a second vessel and that hangs between the first and second vessels to engage the seabed soil frictionally. The vessels can also self-propel to contribute their thrust to the pulling force. The pennant line includes a clump weight such as a bundle of chains that can be repositioned easily for additional pulls by being lifted between the vessels before being lowered to the seabed at a new location.
Claims29
A method of launching a structure across a shore and into water, the method comprising:
- applying a tensile pulling force to the structure through rigging that extends to the structure from a near-shore tug;
- and
- reacting the pulling force through a pennant line that extends from the near-shore tug to a far-shore tug and that frictionally engages seabed soil between the near-shore tug and the far-shore tug to augment the tensile pulling force and resist motion of the near-shore tug towards the shore, wherein the near-shore tug is located intermediate the far-shore tug and the structure.
A pulling arrangement for launching a structure across a shore and into water, the arrangement, in use, comprising:
- a structure to be launched;
- a near-shore tug and a far-shore tug disposed in series with each other and with the structure, the near-shore tug being located intermediate the far-shore tug and the structure;
- rigging that extends to the structure from the near-shore tug;
- and
- a pennant line that extends from the near-shore tug to the far-shore tug and that frictionally engages seabed soil between the near-shore tug and the far-shore tug in order to augment a tensile pulling force applied by the near-shore tug to the structure to be launched and to resist motion of the near-shore tug towards the shore.
Dependencies are inferred from the claim text.