Abstract

The invention relates to a method and apparatus for laying a length of subsea cable from on-board a vessel. The method comprises the steps of releasing the length of cable from the vessel wherein the step of releasing the length of cable comprises the steps of supporting the cable on a portion of on-board cableway, extending a portion of said cableway over-board the vessel and tilting a portion of said extended cableway relative to the portion of on-board cableway. This allows a length of cable to pass over the resulting extended and tilted portion of said cableway toward the seabed whilst in supported engagement with the extended and tilted portion of said cableway. A method and apparatus of moving the location of a cable bight point along a length of cable suspended between a vessel and the seabed is also provided. A cable recovery, repair and re-laying service is also provided.

IPC Classes  ?

• B63B 35/04 - Cable-laying vessels
• H02G 1/10 - Methods or apparatus specially adapted for installing, maintaining, repairing, or dismantling electric cables or lines for laying cables, e.g. laying apparatus on vehicle in or under water

Abstract

A jetting system for an undersea trencher (20) has jetting conduits (50) extending aftward of its trench-cutting jetting swords (30). Jetting conduit nozzles (51) direct liquid radially from their jetting conduits (50) into the trench (F) after the trench (F) is excavated by the jetting sword (30) cutting nozzles (31, 33, 35). The jetting conduits (50) direct sufficient liquid into the trench (F) to maintain the mix of trenched soil and water in the trench along the length of the conduits at not more than a super-critical density, extending the distance in which the product being laid in the trench (F) is able to descend in the trench (F) and increasing the likelihood that the product will be buried at the intended trench depth.

IPC Classes  ?

• E02F 3/88 - Dredgers; Soil-shifting machines mechanically-driven with arrangements acting by a sucking or forcing effect, e.g. suction dredgers
• E02F 3/92 - Digging elements, e.g. suction heads
• E02F 5/10 - Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for making or assembling conduits or for laying conduits or cables
• E02F 5/12 - Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with equipment for back-filling trenches or ditches
• E02F 5/22 - Dredgers or soil-shifting machines for special purposes for back-filling
• E02F 5/28 - Dredgers or soil-shifting machines for special purposes for cleaning watercourses or other waters
• E21C 25/60 - Slitting by jets of water or other liquid
• E21B 7/18 - Drilling by liquid or gas jets, with or without entrained pellets

Abstract

A seabed trenching plow (40) has a chassis (10), a sled (30) and a towing assembly (70). The towing assembly (70) has a pair of wings (71) extending laterally from each side of the chassis (10). The wings (71) are aligned on an axis (75) transverse to the chassis (10) and adapted for connection to a towing line "L". The transverse axis (75) is forward of the center of gravity (81) of the plow (40) and rearward of the sled (30), affording an over the stern releasable and retrievable trenching plow of sufficient weight and strength to excavate a three meter trench in a single pass. To assess the protective capabilities of the trench, a threshold signal indicative of a desired composition of seabed-trench soil is compared with a real-time data signal indicative of the actual to produce an alarm signal when the real-time data signal is not protective-capability compliant with the threshold signal.

IPC Classes  ?

• E02F 5/10 - Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for making or assembling conduits or for laying conduits or cables
• B63B 35/00 - Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for

Abstract

The invention relates to a method of laying and connecting cable between a first structure and a second structure. The first and second structures may be turbine towers or other structures positioned in a body of water. The method includes the step of connecting a second end laying mechanism on the second structure for engagement with a second end portion of the cable. The second end portion of the cable is then engaged with the second end laying mechanism to form a catenary of cable at one side of the second end laying mechanism between the first and second structures, and a tail section at the other side of the second structure. The height of the second end laying mechanism is then adjusted to allow connection of the second end of the cable to the second structure. Second end laying and connecting apparatus for facilitating the laying and connecting of cable between first and second structures is also provided.

IPC Classes  ?

• H02G 1/10 - Methods or apparatus specially adapted for installing, maintaining, repairing, or dismantling electric cables or lines for laying cables, e.g. laying apparatus on vehicle in or under water

Abstract

A method for governing the elevation, attitude and structural integrity of a pressure-containing vessel (V) in a body of liquid (L) counterbalances flotation (MF) and incompressible (MB) ballast mediums against each other in separate serial compartments (CF, CB). Varying the quantity of incompressible ballast medium (MB) allows control of the elevation and attitude of the vessel (V). If the flotation medium (MF) is compressible, varying the quantity of flotation medium (MF) allows control of the ambient pressure of the vessel (V). The method facilitates floating and towing and laying of an undersea pipeline on, to and at a deep water site.

IPC Classes  ?

• B63C 7/08 - Salvaging of disabled, stranded, or sunken vessels; Salvaging of vessel parts or furnishings, e.g. of safes; Salvaging of other underwater objects in which lifting action is generated in, or adjacent to, vessels or objects using rigid floats
• B63G 8/22 - Adjustment of buoyancy by water ballasting; Emptying equipment for ballast tanks
• F16L 1/12 - Laying or reclaiming pipes on or under water
• B63G 8/14 - Control of attitude or depth
• F16L 1/24 - Floats; Weights

Abstract

A plough (104) for excavating a subsea channel is disclosed. It comprises an anchor (101) and a spacing arm (201), the anchor comprising a shank (103) and one or more blade (s) (105) rigidly connected to the distal end of the shank wherein the spacing arm is pivotally connected to the proximal end of the shank and which, in use, maintains the proximal end of the shank at a substantially constant distance from the ploughing surface, thereby controlling the depth of the trench cut in the ploughing surface by the blade (s) as the plough travels over the ploughing surface.

IPC Classes  ?

• E02F 5/10 - Dredgers or soil-shifting machines for special purposes for digging trenches or ditches with arrangements for making or assembling conduits or for laying conduits or cables
• B63B 21/42 - Anchors pivoting when in use with one fluke of ploughshare type