The operator of the Basker Manta oil project said it had used a remotely operated vehicle to inspect the damage after the vessel broke free from its mooring on Thursday night and drifted away.

“A pin in one of the chain shackles has become dislodged, allowing the upper mooring elements to detach from the three-point mooring at the nodal point,” Anzon said.

“The mooring system itself is in good condition, with no reason to question its integrity.”

The hose that transfers oil from the Crystal Ocean floating production storage and off-take (FPSO) vessel was also damaged, Anzon said, as it took the load of the Basker Spirit when the shackle broke.

Anzon said while it has spare hoses in stock, it needed to deploy a specialised construction vessel to repair the full mooring system and allow full production to restart.

It expects to have one of three such vessels in the field in the second half of August, subject to negotiations with the vessel owners.

Until then, Anzon and partner Beach Petroleum plan to use the FPSO to shuttle oil to the Basker Spirit while it is moored at port. They expect to produce about 3000 barrels of oil per day using this method.

Before the accident, the Basker Manta project had been producing about 10,000bopd – still only half of the planned rate of 20,000bbls.