JEKYLL ISLAND, Ga. (AP) -- Coast Guard rescuers pulled four trapped men alive from a capsized cargo ship Monday, drilling into the hull's steel plates to extract the crew members more than a day after their vessel overturned while leaving a Georgia port.
All four were described as alert and in relatively good condition and were taken to a hospital for further evaluation.
"Best day of my 16-year career," Lt. Lloyd Heflin, who was coordinating the effort, wrote in a text message to The Associated Press.
A video posted online by the Coast Guard showed responders clapping and cheering as the final man, wearing only shorts, climbed out of a hole in the hull and stood up.
Three of the South Korean crew members came out in the midafternoon. The fourth man, who was trapped in a separate compartment, emerged three hours later.
The rescues followed nearly 36 hours of work after the Golden Ray, a giant ship that carries automobiles, rolled onto its side early Sunday as it was leaving Brunswick, bound for Baltimore.
"All crew members are accounted for," Coast Guard Southeast wrote on Twitter. "Operations will now shift fully to environmental protection, removing the vessel and resuming commerce."
South Korean President Moon Jae-in sent a letter to President Donald Trump to express gratitude over the successful rescue of the men, saying that the news brought "huge relief and joy" to South Koreans.
The presidential Blue House said Moon also sent a letter to U.S. Coast Guard Commandant Karl Schultz and praised the "courage and dedication" of Coast Guard members involved in the rescue.
In the hours immediately after the accident, the Coast Guard lifted 20 crew members into helicopters before determining that smoke and flames and unstable cargo made it too risky to venture further inside the vessel. Officials were concerned that some of the 4,000 vehicles aboard may have broken loose.
That left responders looking for the remaining four crew members. At first, rescuers thought the noises they were hearing inside could be some of the vehicles crashing around. But by dawn Monday, they were confident that the taps were responses to their own taps, indicating someone was alive inside.
"It was outstanding when I heard the news this morning that we had taps back throughout the night," Capt. John Reed said. Those sounds helped lead rescuers to the right place on the 656-foot (200 meter) vessel and provided motivation.
"They were charged up knowing the people were alive," Reed said.
On Monday morning, rescuers landed on the side of the Golden Ray and rappelled down the hull. Heflin, who was coordinating the search, said they found three men in a room close to the propeller shaft, near the bottom of the stern. Responders began drilling, starting with a 3-inch (7.5-centimeter) hole. Coast Guard officials brought the ship's chief engineer, who was rescued Sunday, out to the ship to translate, and found the three men were "on board and OK," as Heflin put it.
Reed said rescuers passed food and water through the hole to the men. They also provided fresh air to the propeller room, which Reed said was even hotter than outside, where the high was 93 degrees (34 Celsius).
Responders set up a tent on the hull and began drilling additional holes, eventually making an opening large enough to insert a ladder and help the men climb out.
"It was like connect the dots," Reed said of the hole, which grew to 2 feet by 3 feet (0.6 meters by 1 meter).
The fourth rescue was a greater challenge. That crewman was behind glass in a separate engineering compartment on another deck, Reed said.
The Golden Ray is now stuck in the shipping channel, closing one of the busiest U.S. seaports for shipping automobiles. One ship is unable to leave port and four more are lined up outside waiting to come in, according to ship-tracking website Marine Traffic.
A statement issued Monday by the South Korea foreign ministry said the crew members were isolated in an engine room. It said 10 South Koreans and 13 Filipinos had been on board, along with a U.S. harbor pilot, when the ship began tilting.
Position records for the Golden Ray show the ship arrived in port in Brunswick Saturday evening after making the short sail from a prior stop in Jacksonville, Florida. The ship then departed the dock in Brunswick shortly after midnight and was underway only 23 minutes before its movement stopped in the mouth of the harbor where it capsized, according to satellite data recorded by Marine Traffic.
Port officials were "working closely with the Coast Guard to reopen the channel," Georgia Ports Authority Executive Director Griff Lynch said in a statement after the final man was rescued.
The cause of the capsizing remains under investigation. Marine Traffic shows the Golden Ray overturned as it was passed by another car carrier entering St. Simons Sound.
At the time, the skies were clear and the weather calm, with a southerly breeze of only 5 miles per hour, according to National Weather Service records.
Many of those rescued were taken to the International Seafarers' Center in Brunswick. Sailors arrived with only what they were wearing when rescued. A restaurant donated a meal, and the volunteer-run center provided the seamen with clothes, toiletries and Bibles.
The vessel is owned by Hyundai Glovis, which carries cars for automakers Hyundai and Kia as well as others.
In a statement, the company thanked the Coast Guard for saving the crew and sought to assure the public that it would now focus on "mitigating damage to property and the environment."