PORT FOURCHON, LA. -- Families anxiously awaited news of the 12 people missing from a capsized oil industry vessel Thursday while stormy weather delayed divers from searching for survivors.

Rescuers don't know whether any of the missing might be caught inside the lift boat called the Seacor Power that flipped over Tuesday in hurricane-force winds and high seas about 8 miles (13 kilometres) off the coast of Louisiana, Coast Guard spokesmen said.

"There is the potential they are still there, but we don't know," Petty Officer 2nd Class Jonathan Lally said Thursday. "We're still searching for 12 people because there are 12 still missing."

The Coast Guard said divers were on the scene Thursday afternoon but could not confirm whether they'd begun diving.

A handful of the missing workers' family gathered at a two-story fire station at Port Fourchon, a sprawling port where much of the industry that services the oil rigs in the Gulf of Mexico is based.

Workers from across Louisiana and other parts of the country arrive at the port to load up on the fleet of helicopters and ships that take them to the oil rigs miles out for long stretches of work. The flat landscape is punctuated by cranes where cargo can be loaded or unloaded and docks or hangers to make repairs.

In a nearby harbour, shrimping boats were docked, and fishing camps stood raised on stilts to protect them from incoming storms.

Marion Cuyler, who is engaged to crane operator Chaz Morales, spoke to reporters Thursday outside the fire station after briefings by executives with boat owner Seacor and the Coast Guard. She said they were told that divers entered the water Thursday morning, paused because of rough weather and were returning later. She said she believes all 12 missing people are on the vessel.

"I heard from someone that was rescued that they are in the boat -- which is why we needed those divers in the water, as quickly as possible," she said.

Cuyler wavered between optimism and fear as she spoke but held out hope that Morales was in a part of the ship that had air after the accident and would be rescued alive.

"Hopefully, they are all in one room, and they can just rescue them all in one day," she said.

She said she and other family members are frustrated and want answers about why the boat went out in the first place.

"I asked, `Who gave the orders' and of course -- silence," she said. Cuyler said she'd told her husband-to-be that he shouldn't be going out in such weather. "And he knew they shouldn't have been going out."

A total of six people were rescued Tuesday when the ship capsized, and the Coast Guard Thursday released new details of how the rescue unfolded. The crew of a Coast Guard ship that answered the ship's distress signal, arriving about 5:10 p.m. Tuesday, saw five men clinging to the hull, said Petty Officer 3rd Class Carlos Galarza.

A helicopter crew from Bristow, a marine company, lowered life vests and VHF radios to them, he said. Two of the men dropped into the water and were picked up by the Coast Guard. About the same time, Good Samaritan vessels rescued four other people, he said. The Coast Guard was also able to talk to the three people still on the ship's hull using the radios that had been dropped. Later Tuesday night the Coast Guard was notified that one person had fallen in the water and wasn't seen again.

Shortly before 10 p.m., the two remaining people told the Coast Guard they were going back inside, and that was the last time the Coast Guard spoke with them, Galarza said.

On Thursday, Coast Guard members in a boat made their way to within a few yards of the capsized vessel and tried throwing a hammer at the hull in an attempt to make contact with potential survivors, the agency said.

One person's body was recovered from the water Wednesday as searchers scanned an area roughly the size of Hawaii, the Coast Guard said. The Coast Guard said it had been classified as a "major marine casualty" with the National Transportation Safety Board joining the investigation.

The Lafourche Parish Coroner's Office identified the dead man as David Ledet, 63, of Thibodaux -- a town in southeastern Louisiana where many people work in the oil industry.

"Capt. Dave was awesome," Joshua Segura, a mate and crane operator, said on Facebook. He said he had worked with Ledet before moving to another offshore company, describing him as one of the nicest and most humble people he's met.

"Captain David has been on that boat over 15 years and is one of the most experienced captains I've ever worked with," he wrote.

Part of the overturned ship's hull and one of its legs were still visible, leaving most of the bulky vessel underwater, in an area 50 to 55 feet (15 to 17 metres) deep, according to the Coast Guard. The ship has three long legs designed to reach the sea floor and lift the boat out of water as an offshore platform.

The vulnerabilities of lift boats in storms have been known for years, and federal authorities have investigated multiple deaths on them. Four people on board the Trinity II died in September 2011 in the Gulf of Mexico when large waves struck its hull. Then in July 1989 a lift boat sank off the coast of Louisiana in storms associated with Hurricane Chantal. Ten of the 14 people on board died.

Coast Guard Capt. Will Watson said winds were 80 to 90 mph (130 to 145 kph) and waves rose 7 to 9 feet high (2.1 to 2.7 metres) when the Seacor Power overturned.

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Martin reported from Atlanta. Photographer Gerald Herbert contributed to this story from Grand Isle, Louisiana and reporters Janet McConnaughey and Rebecca Santana contributed from New Orleans.