EFFORTS TO save the world's largest floating oil platform failed as the giant Petrobras 36 rig sank in rising seas last month.
The 32,000t P-36 was holed below the waterline after three explosions ripped through the semi-submersible platform in the Roncador oilfield, 125km off the Brazilian coast, killing 10.
The structure is now resting on the seabed in 1,362m of water.
Contracted to Brazillian oil conglomerate Petrobras, the rig took up position last year.
The steel platform deck was supported by two steel pontoons, each supporting a pair of cylindrical steel legs, and anchored with 16 polystyrene ropes, 187mm in diameter. Its operating draft was 22m.
A Petrobras spokeswoman said that the cause of the blasts was unknown but that the first major breach, inundated compartments of one pontoon, with the structure developing a 28infinity list.
A team of more than 300 people and Dutch salvage specialist Smit Tak pumped in compressed air and non-explosive nitrogen in an attempt to expel water from the pontoon and level the rig. 'We had stabilised it for a time, but once the list developed, water came in through ventilation openings, ' said a spokesman, and Smit Tak evacuated its team.