UPDATE: A Transocean spokesman said the Marianas rig is stable and the company will take at least a week to tow and inspect it.

“Efforts are underway to de-moor the rig and have it towed to sheltered waters to inspect the damage that has allowed water to enter,” said spokesman Guy Cantwell.

Transocean will conduct an internal investigation into the cause of the incident once the rig is moved to shallower waters, he said. Workers are in the process of disconnecting the system of wires and anchors that hold the rig in place so that it can be towed.

As of yesterday, 13 workers were on site, Cantwell said, and more could be added if necessary.

Kosmos Energy, a Dallas-based exploration and production company, said it was to receive the Marianas rig at its well site near Ghana on or about July 10. In a press release, the company said its project will be delayed because “the rig was rendered temporarily inoperable following a reported anchor-handling incident.”

Kosmos said the damage occurred while the Marianas was being prepared for transportation to its well. The company is looking for a substitute rig.

By HARRY R. WEBER and DINA CAPPIELLO

Associated Press

The owner of the rig that sunk in the massive Gulf oil spill last summer was having problems today with another one of its deepwater drillers — this time off the coast of Africa.

Transocean spokesman Guy Cantwell said that the rig called Marianas began to take on water near Ghana as it was preparing to move to another location. The rig, currently under contract to Italian oil company Eni, was not drilling at the time. It’s a moored semi-submersible rig that lifts its anchors when it prepares to move. It was doing that at the time of the mishap.

Transocean evacuated 108 non-essential workers as a precaution.

Thirteen remained on board to monitor the situation. Cantwell described the situation as stable and under control, though he could not say for sure whether workers were able to stop water from coming aboard. No one has been injured, he said. An investigation was under way, and Cantwell said it was too soon to speculate on what caused the Marianas to take on water.

On Oct. 21, 2009, the Transocean Marianas arrived on location to start drilling an exploration well on the Macondo prospect in the Gulf.

Several days later, drilling commenced, but was halted on Nov. 28, 2009, when the Marianas underwent repairs for damage caused by Hurricane Ida. British oil giant BP leased another rig, the Deepwater Horizon, to complete drilling operations on its well a mile beneath the sea. The Deepwater Horizon began its work in February 2010.

Two months later, 11 workers were killed when the Deepwater Horizon exploded off Louisiana, leading to the worst offshore oil spill in U.S. history.

Swiss-based Transocean has been under scrutiny since the Gulf disaster, but the company has largely blamed others, especially BP, for what happened in the Gulf.

In Washington, U.S. Rep. Edward Markey, a Massachusetts Democrat and ranking member of the House Committee on Natural Resources, said in a statement today that the fact that the Marianas originally drilled the well that eventually blew and resulted in the Gulf spill shows that deepwater offshore drilling “was, is, and will continue to be an inherently risky business until the highest possible safety standards are put in place in America and worldwide.”

There was no immediate comment from Eni.

Transocean’s stock fell today by $2.04, or 3.2 percent, to $62.23. Some analysts called it an overreaction.