Work continues on the OS 35

Overnight work continued onboard grounded bulk carrier OS 35 (IMO 9172399) during the night of September 4th. The situation in both the engine room and cargo hold 5 remained stable. Pumping operations were ongoing, further reducing the amount of oil onboard the vessel.

These operations concentrated on the lube tanks of the engine room, all of which had now been pumped out.

High wind conditions off the eastern side of the Gibraltar peninsula, where the vessel was grounded last week, created difficulties for the response teams on site, and have impacted the efficacy of the booms placed around the vessel to prevent pollution spread. The second boom around the vessel was reported as displaced, but not damaged. Similarly, the boom at Catalan Bay had also been displaced, with some parts of the boom reaching shore.

Works to ameliorate the impact of the problem were ongoing.

Meanwhile in Little Bay no new oil was reported. In Sandy Bay some oil patches on groynes and small patches were scattered along the main beach. In Catalan Bay a small sheen patch was observed offshore. At the eastern and western Beach no oil was reported.

Through to September 4th there had been continuous pumping of fuel from the vessel although at a slightly slower pace than predicted.

AquaGib conducted a diving inspection early in the morning of September 3rd at Little Bay, which confirmed that their salt water intake inlets are unaffected.

A sorbent boom was deployed to protect Sandy Bay, where there was evidence of sheening and small amounts of oil on the shore. A clean up operation to remove it was underway.

The vessel’s own systems could not safely be used to pump fuel out. The salvors were therefore having to rely on independent off-ship systems to pump out the oil.

Dive teams were investigating the source of water ingress. Work was underway to clear away any non-essential materials that could potentially add to the levels of contamination.

The majority of fuel had already been successfully removed with the ongoing work consisting of removing residual fuel. Operations to pump out water from the engine room commenced in the afternoon of September 3rd and were largely successful, in that the situation had been stabilized. Divers were working to identify the source of the leak into the engine room.

Given the circumstances that have arisen in respect of the flooding of the engine room, water has been also pumped out of cargo hold 5 to add to the buoyancy of the aft section of the vessel in an attempt to mitigate the impact of the leak on the structural integrity of the vessel.

The vessel’s forward Tank 1 is split into 4 distinct parts – Port, Centre Port, Starboard and Centre Starboard – and extraction was taking place section by section.

Tank 1 Centre Starboard looked to have suffered a minor breach which was letting water into the tank. The extraction from this tank therefore needed to be achieved by relying on the pressure of the water entering the tank pushing the oil upwards toward and through the tank vent. This was necessarily a slow process that needed to be managed carefully in order not to increase the amount of water that was mixed in with the fuel when extracted. It was estimated that there are approximately 80 tonnes of heavy fuel oil in Tank 1 Centre Starboard.

1999-built, Tuvalu-flagged, 20,947 gt OS 35 is owned by Oldstone Cargo Ltd care of manager Oldstone Management Ltd of Piraeus, Greece. It is entered with British Marine on behalf of Oldstone Cargo Ltd.