Semi-submersible drilling rig ran aground on coast of Isle of Lewis in Scotland as it was being towed to Malta

Fourteen salvage experts have boarded the drilling rig that ran aground on the coast of the Isle of Lewis in Scotland last week, as the official overseeing the operation confirmed it could take weeks before the stricken oil platform can be moved.

The 17,000-tonne semi-submersible rig, Transocean Winner, ran aground close to Dalmore beach last Monday as it was being towed from Norway to Malta and its towline snapped in heavy seas.

Hugh Shaw, the secretary of state’s representative for maritime salvage and intervention, told BBC Alba that any attempt to refloat the rig was still weeks away.

The platform was carrying 280 tonnes of diesel, and specialists believe two of the four storage tanks were damaged when it hit rocks near Carloway, with a potential loss of 53 tonnes of fuel. But there has been no sign so far of an oil slick or reports of pollution.

Smit Salvage confirmed on Monday that the remaining two diesel oil tanks in the hull were intact and plans were now under way to transfer their contents – a total of 137 tonnes – using onboard pumping systems to other tanks above the water line.

Meanwhile, the salvage team, which includes staff from the rig’s owner, Transocean, will continue their damage assessment and preparations for the eventual refloat. A wire will be run between the shore and the rig to enable supplies and equipment to be delivered to those working onboard.

The Maritime and Coastguard Agency is continuing to impose a 300-metre exclusion zone around the popular surfing spot covering sea and air, to prevent onlookers hampering the salvage teams and to prevent drones being used in the area. The Scottish operational environment group is closely monitoring the incident.