Catalogs >
Royal IHC >
SEVEN OCEANS

SEVEN OCEANS
7Pages

Catalog excerpts

Seven Oceans 28-06-2007 09:36 Pagina 1 SEVEN OCEANS MERWEDE SHIPYARD DELIVERS RIGID REELED PIPE LAY / OFFSHORE CONSTRUCTION VESSEL Builders: Merwede Shipyard, Hardinxveld-Giessendam, Netherlands Owners: Subsea 7, Aberdeen, Scotland In a joint effort with Huisman-Itrec from Schiedam, Merwede Shipyard has recently delivered ‘Seven Oceans’, a 160 m pipe-laying ship. While Merwede Shipyard was responsible for the design and production of the ship systems and the integration of the pipelay spread, Huisman Itrec took on the design and manufacturing of all the pipe-laying systems. The ‘Seven Oceans’ is a deepwater rigid and flexlay lay vessel intended for the installation of rigid pipes up to a diameter of 16” on the ocean floor in depths up to 3000 m.The ship can deploy two Remote Operated Vehicles (ROV’s) which can monitor the pipelaying activities from nearby. Besides pure pipelaying, the ship will be used for subsea construction, ROV support and survey activities.The vessel will be mainly operated in the deepwater oil fields offshore Brazil and West-Africa. The main reason Subsea 7 opted for the Merwede Shipyard - Huisman Itrec combination is the turnkey project approach and the guarantee of a delivery on time. The turnkey project approach was essential as Subsea 7 did not want to get caught in-between a yard and the supplier of the pipelay installation.The guarantee of a delivery on time was essential as Subsea 7 wished to engage in projects for ‘Seven Oceans’ when the building had not yet started. The new ship will allow Subsea 7 to lay pipes at greater depths than possible until now. Loading procedure Centrally in the ship is a large reel for the storage of the rigid pipe. In a typical loading scenario, the ship will anchor herself with her stern facing the shore. The pipe can then be reeled-in from a production facility on shore, almost eliminating the need to weld or coat pipes in the difficult conditions off-shore.The main reel has a capacity of 3500 tons, the equivalent of 12 to 120 km of pipe, depending on the diameter and weight of the pipe. As the pipe is wound upon the reel, it is subjected to a first plastic deformation. The second and last deformation follows when the pipe is straightened again for installation. Any consequent plastic deformations are not allowed, as

Open the catalog to page 1

Seven Oceans 28-06-2007 09:36 Pagina 2 ward from the vertical position through about 45 degrees.The angle is adjusted to the water depth and the characteristics of the pipe to be laid. The lower position is mainly used when loading and when pipelaying in shallow waters.The latter is called S-laying, as the pipe takes the shape of a stretched-out letter S during the procedure. When pipelaying in deep waters, the tower is in the vertical position.This procedure is called J-laying. PLET handling Pipeline End Terminations (PLETs) are manifolds which are installed in subsea pipeline systems.The...

Open the catalog to page 2

Seven Oceans 28-06-2007 09:36 Pagina 3 Hull The ships hull lines are designed to give the vessel good seakeeping performance. To be able to lay pipe in a seastate with a significant wave height hs=3.0 meter the vessel is given ample freeboard in order to avoid deck wetness. Roll accelerations are reduced by 2 passive anti roll tanks. The vessels trial speed at design draught with 3 thrusters @ 90% of maximum power is 14.5 knots. On the stern, two extensions above the waterline allow for the handling of the stern anchors and provide a good vantage point to monitor the pipelaying activities....

Open the catalog to page 3

Seven Oceans 28-06-2007 09:36 Pagina 4 engines provide a total of 20.160 kW of power.The consumers for propulsion include the following: - 3 Wartsila/Lips azimuthing thrusters (each 2.950 kW); - 2 retractable azimuthing bow thrusters (each 2.400 kW); - 1 tunnel bow thruster (2.200 kW). Each of these thrusters is located in a separate room.The retractable bow thrusters are more effective and less noisy, but a tunnel thruster was necessary for maneuvering in shallow water and ports.The engines can run on cheaper IFO-180 during transit and switch to MGO in dynamic positioning mode to avoid...

Open the catalog to page 4

Seven Oceans 28-06-2007 09:36 Pagina 5 The A & R winch is located below the aft deck in the aft ship is a room for the abandonment and retrieval (A&R) winch and a heeling pump room. In the double bottom are a number of bunker tanks and technical fresh water tanks, which can be used to fill newly laid piping. In this way, the pipe loses its buoyancy and does not corrode because of salt water. Stability Catch-22 The stability requirements had a profound effect on the design of the vessel. Different situations require very different stability characteristics. During pipelaying, the weight of...

Open the catalog to page 5

Seven Oceans 28-06-2007 09:36 Pagina 6 Electronics Nederland BV. The Integrated Navigation and Command System NACOS 35-5 includes a.o. the following components: – one X-band Chart Radar; – one S-Band Chart Radar; – two ECDIS-systems / ChartPilot-1100 (for paperless sailing); – one TrackPilot-1100,Track keeping system with dedicated Conning Monitor; – one NACOS slave station for the DP desk with Trackpilot operation panel – one AIS unit (DEBEG-3400), fully integrated in the NACOS/ Radar system; – one complete VDR system/ DEBEG-4300; – one speed log; – one Echo sounder Skipper GDS 101; – one...

Open the catalog to page 6