GTS Subsea completes deep-water coring contract off the west coast of ScotlandProjects and Operations // August 16, 2006
GTS Subsea, the Surrey and Somerset based, independent site investigation business in the UK has successfully completed its part of a cable route survey between Oban and Mull.
The contract required GTS Subsea to mobilise a 3m, high performance, electric vibrocorer as part of a cable route survey for Scottish and Southern Electricity via the prime contractor Osiris Projects.
Over the course of the contract, twenty-two cores were taken over a proposed cable route from the Scottish mainland near Oban via the Island of Kerrera and onwards to the Isle of Mull.
Due to the route the cable has to take between the mainland and the islands, a large number of cores had to be taken in deep water.
Several of those cores were taken in water depths of over 200m and the deepest of all was some 220m. Excellent penetration and recovery was obtained at all depths (bedrock permitting) in material including clays, sands and angular gravels.
The work itself was carried out from a small, 15m multicat, with surveyors from Osiris Projects carrying out the vessel positioning and navigation.
The compact vibrocore spread proved that it could work well within the constraints of a smaller vessel. However, for jobs requiring greater sample depths, the flexibility of GTS Subsea’s vibrocorer design means it can also be quickly configured to operate in longer modes (for example 6m).
GTS Subsea also put into service the first production run of its new, toughened, umbilical. This latest addition to the equipment spread carries both power conductors and four twisted pairs for bi-directional data, video and control signals to the corers. The umbilical proved very easy to manage, even during spring tides, and the jacket has shown itself to be extremely hardy.
Fergus Taylor, owner of GTS Subsea, said: "We were delighted with the levels of recovery achieved from such a wide range of materials and were really pleased with the performance of the new umbilical in the water column. The job really demonstrated how versatile the equipment spread is and also how well our team can react to on-site changes in requirements.”