The Chilean navy floated a ring of booms around a grounded Peruvian ship Thursday in an effort to contain an oil spill that has created a slick more than a half-mile long in the Antarctic, a spokesman said.

The navy spokesman, Lt. Cristian Carbone, said in a telephone interview that "our priority task at this point is to contain the spill.""Floating the Humboldt comes next," said Carbone, who was in Punta Arenas, 1,500 miles south of Santiago.

He said divers plunged into the frigid waters to evaluate the damage to the Humboldt's oil tanks and begin sealing them.

Divers from nearby Uruguayan and South Korean Antarctic stations also are participating in the operation, according to a navy communique.

The 1,980-ton Humboldt ran aground shortly before midnight Sunday at the entrance of Marion Cove, on King George Island. All 64 scientists and sailors aboard were rescued by the British Royal Navy's ice patrol ship Endurance.

On Wednesday, however, a group of sailors were back on the ship to start planning the operation to float it and await for the arrival of the Chilian cutter Yelcho to coordinate the cleanup. The Yelcho arrived today.

Carbone said the barrier installed around the Humboldt is the same type used successfully a month ago to contain a mayor oil spill caused by the Bahia Paraiso, an Argentine navy vessel that run aground off the Antarctic peninsula.

The oil slick created by the Humboldt had grown to more than a half-mile long and 150 feet wide by Wednesday afternoon, more than double its size of a day earlier, according to the Chilean navy.

Peruvian officials, however, claimed the spill is minimal.

Carbone stressed that the priority was to clean up the spill, and then try to float the ship. "The floating operation will be undertaken earlier only if experts consider it is necessary to contain the oil spill," he said.