A 300-square mile debris field dotted with shipping containers and an empty lifeboat is being searched for survivors by the Coast Guard, which now believes the TOTE Maritime ro/ro container vessel El Faro sank close to its last reported position in Hurricane Joaquin.

“We are still looking for signs of life,” said Capt. Mark Fedor at a Monday morning press conference at Coast Guard Air Station Miami. Fedor said unidentifiable human remains in a survival suit had been seen in the water by a rescue swimmer from one search helicopter, and a damaged lifeboat found with markings showing it came from the El Faro.10.5.15 ElFaro LifeRingAn empty life ring from El Faro was recovered by the Coast Guard on Oct. 3. Image via USCG.

The searchers are shifting efforts “to focus on possible persons in the water,” Fedor said, checking on every sighting of survival gear. Fedor said the 33-member crew was well trained, but cautioned they were up against horrendous conditions for evacuating a sinking ship.

“They would have been abandoning ship in a category 4 hurricane, with 140 mph winds and seas up to 50’,” Fedor said.

Given warm water temperatures in the area east of the Bahamas, it is conceivable survivors could live four to five days immersed, he said.

“We are not going to discount somebody’s will to survive,” Fedor said.

The 735’x95” El Faro departed on its usual route from Jacksonville, Fla., to San Juan, Puerto Rico, on Sept. 29, when Joaquin was still at tropical storm strength. The ship was carrying 391 containers on the cargo deck and more than 200 vehicles and trailers on the lower vehicle deck.

TOTE company officials said the crew was monitoring the storm and following procedures to avoid the worst weather, and captain Michael Davidson reported good weather Wednesday. But Coast Guard officials think the complicated track taken by Joaquin may have caught up with the ship, the Bangor Daily News reported.

Contact was lost with the ship Thursday, and the Coast Guard received a single Inmarsat message from the crew, saying the ship had lost power and developed a 15-degree list. The message said there had been some flooding but the crew had it under control, according to the Coast Guard.

The search is continuing with three cutters, three ocean tugs hired by TOTE, and Coast Guard and Navy aircraft, Fedor said. The National Transportation Safety Board announced Monday afternoon that it would launch an investigation into the loss of the El Faro, with a team traveling to Jacksonville on Tuesday morning.