US 9,174,705 B2 · Compensated lashing of tender assist drilling unit to a floating production facility

Abstract

A system of lashing a tender assist drilling unit (TADU) to a floating production platform includes a plurality of lashing lines reeved over a hydraulic-pneumatic tensioning system sheave assembly and a plurality of fixed anchor points to the above water line section of the production platform hull structure. The hydraulic-pneumatic tensioning device will, when in tensioning mode, compensate and control the relative movement between the two floating bodies. The hydraulic-pneumatic tensioning system will also enable lashing pre-tension adjustments during operations and fine-tuning of system performance can be done site-specific based on lessons learned. The hydraulic-pneumatic tensioning device will, when in hydraulic lock mode, enable a fixed lashing line system. This will by the means of the first units mooring winch system enable; a winch-in for close proximity during heavy lifting; or an efficient lashing pay put during extreme weather preparation for increased separation between the two units.

Claims13

Dependent claims

A system for lashing a first structure to a second structure, the first structure having a buoyant hull and floating in a body of water, the system comprising:

a plurality of winches attached to the first structure;
a plurality of hydraulic-pneumatic tensioning systems attached to the first structure,
a plurality of fixed anchor points on the second structure;
and,
a plurality of lashing lines, each of the plurality of lashing lines extending from a respective one of the plurality of winches, through a corresponding one of the plurality of hydraulic-pneumatic tensioning systems and fixed at a corresponding one of the plurality of fixed anchor points;
wherein each of the hydraulic-pneumatic tensioning systems comprise:
a first sheave assembly fixed to a first end of a hydraulic cylinder and rod assembly;
a second sheave assembly fixed to a second end of the hydraulic cylinder and rod assembly;
an accumulator operably connected to the hydraulic cylinder and rod assembly;
and
a fail safe valve between the accumulator and the hydraulic cylinder and rod assembly;
wherein the operation of the fail safe valve will make the lashing system fixed by hydraulic locking.

9 more elements

Dependencies are inferred from the claim text.

Compensated lashing of tender assist drilling unit to a floating production facility

Life of this patent

Compensated lashing of tender assist drilling unit to a floating production facility

Life of this patent

Abstract

Claims13