Pharos Offshore Group has started construction of a newly designed remotely operated vehicle (ROV) specifically for the offshore wind farm cable market.
The new Inter Turbine Array Trencher, the ITAT 800™, is an 800 HP (600 kW) self-propelled trenching ROV that can be more easily manoeuvred by the operators onboard its support ship than a towed plough. It uses a unique water jetting technology to cut the seabed. The technology is safer than a metal plough share or mechanical cutter around the valuable power cable. The water jets “fluidize” the sea floor material and allow the interconnecting power cables of a wind farm to sink in up to three meters deep.
Wind farm developers and cable installers can also gain scheduling flexibility when using a trenching ROV like the ITAT 800™ when compared to a conventional cable ploughs. The inter-array cable can be laid on the sea floor to connect the wind turbines more quickly and then a process called Post Lay Inspection and Burial – PLIB is used to complete the burial process using a trenching ROV.
This industry practice of subsea cable burial ensures cable protection in distribution systems worldwide and is widespread best practice in the telecoms industry. Left unprotected, power cable, fiber optic telephone cable and oil and gas pipe is vulnerable to damage from ship anchors, fishing activity and other threats.
The design of the ITAT 800™ has been a priority for Pharos Offshore Group due to demand from customers for safer trenching methods, particularly for the offshore wind market. The need to operate around the inter turbine array cable, also called infield cable, with extreme care is due to the multiple short runs of cable within a confined, precisely planned area of the turbine foundation array. Over the last eight years, many insurance claims have been needed by offshore developers to cover the costs of damage to cables during the installation and burial processes currently used.
“ We are excited to bring together the expertise of our operational personnel and designers, with the construction of the ITAT trenching ROV. We think this will fulfill a critical need of the growing offshore wind farm market,” says Phil Walker, CEO of Pharos Offshore Group.
The ITAT 800™ is about the size of large car. The concept and the design have been developed from the experience gained from many tens of thousands of kilometers of cable burial in the telecoms and oil and gas sectors. It is built using many proven and readily available Commercial-Off-The-Shelf (COTS) parts -this reduces the system’s initial price tag, and helps keep ongoing operating costs low. The ITAT’s maneuverability, survey equipment, low profile and jetting power provides the flexibility required for infield cable work.
The cable maintenance version of the ROV named the MENTOR 800™ provides the ITAT’s powerful jetting capability to depths up to 3000 meters for deeper cable and O&G pipeline work. Interchangeable tooling systems provide the flexibility to accommodate the most demanding undersea cable installation and maintenance operations. Pharos Offshore Group. plans to sell and lease multiple vehicles to serve Round 3 wind farm projects in the United Kingdom and upcoming projects in North America.
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Source: Pharos Offshore Group, August 25, 2011;