Five Oceans Services - Mull

Projects : Power Cables : Mull - Coll Power Link

Five Oceans Services was commissioned by Scottish and Southern Energy plc to install a 11 KV Power Cable between the Islands of Mull and Coll. The cable was installed to replace a defective existing cable that was laid in 1987. The new cable was laid parallel but south of the existing cable with a distance between the two cables of approximately 150 m. The projected cable route was approximately 16.0 km.

The installations comprised cable lay between the joint locations on both islands and trenching of the cable to a minimum depth of 1.0 m below the seabed, where possible. Cable lay was carried out by Five Oceans Services' dedicated cable lay vessel Sea Spider, whereas the trenching of the cables was carried out using the Smartjet 1150. In order to minimize the risk of creating freespans during cable lay, touch down monitoring was carried out using the trencher as inspection ROV.

Characteristics of the Cable:
Type of Cable	:	HVAC Cable
Total Length	:	16 km
Weight (in air)	:	22 kg/m
Outer Diameter	:	94 mm
Min. Bend. Rad.	:	5 m

In order to successfully complete the Mull - Coll Power Link, Five Oceans Services utilized specialized cable equipment. The equipment utilized included, but was not limited to:

Cable loading equipment
Cable lay equipment
Cable trenching equipment

In addition to the above, dedicated support equipment such as high accurate positioning systems (DGPS and USBL), as well as typical inspection and monitoring equipment ensured that a high level of confidence was achieved and maintained throughout the project.