A rescued surfer told his family he had "made himself at peace" with not surviving after 32 hours adrift at sea.
Matthew Bryce, from Airdrie in North Lanarkshire, was found 13 miles off the Argyll coast on Monday night after going surfing on Sunday morning.
From his hospital bed in Belfast, he said he watched the sun set, believing he would not survive another night.
His parents John and Isabella described their anguish as they waited for news.
The 23-year-old told BBC Scotland's Jackie Bird how it had started as "just a normal day".
He said he had driven to Westport car park in the Kintyre peninsula on Sunday morning, waxed his surfboard then gone into the sea about 11:00 to catch some waves.
The day soon turned into a nightmare and he began to panic as tides and winds carried him out to sea.
"The wind and water was just relentless," he said.
At one point he got back to within about a mile of land, only for the tide to change direction.
"It got to the point where my paddling was ineffective, but I was doing it to keep myself warm."
If he had been surfing he said he might have stayed in the water for about four hours, but now the sun was setting and he was carried further out to sea.
Mr Bryce said his hopes were raised when he saw fishing boats, but his shouts went unheard and they sailed off.
He described how deep fear set in when night fell.
"It was incredibly lonely and quiet because there was just nothing - just waves," he said.
"I hadn't seen any helicopters.
"I was thinking I was going to die - I was almost convinced.
"I didn't think I would see sunrise."
Mr Bryce said he then saw ships, and since he was well out of the coastguard search area, he decided to try and get into a shipping lane in the hope someone might see him.
He continued to paddle towards the ships through the night.
By daylight he was starting to pass out and fall off his board.
He continued to drift through the day and as night approached again he said he was resigned for death.
"I knew I wasn't going to make another night, so I was watching the sunset," he said.
"Then a helicopter flew over me."
Terrified that he wouldn't be spotted he jumped off his board and held it above him and started waving it.
After thinking they had missed him, he described the moment his luck changed.
"But then they turned round and when I saw them turn it was indescribable," he said.
"I can't describe it at all.
"These guys were the most beautiful sight I had ever seen.
"I owe them my life."
He was winched from the North Channel by the search and rescue helicopter at about 19:30 on Monday.
Police Scotland and the coastguard had launched a large-scale search earlier that day, including rescue teams from Campbeltown, Southend, Gigha, Tarbert and Port Ellen.
During the day of the coastguard search, his parents John and Isabella, who are both nurses, were with their eldest son at their caravan near Campbeltown.
Mrs Bryce said she spent the day looking at the water praying her son would be found alive.
Mr Bryce said while he had tried not to give up hope, he had started discussing with his brother-in-law, the process of who would go to identify his son's body when it was found.
He said: "We tried to keep strong, but it was just getting harder and harder."
Describing the moment his phone rang, he said: "I walked outside the caravan because I think it's the worst news possible.
"It was the police inspector and all he said was 'he was found alive'.
"I was outside crying my eyes out and obviously Isabella and my son thought we'd received the worst possible news.
"So I had to run in and tell them 'he's alive, he's talking to the coastguard'."
About half an hour later they were able to speak to their son on the phone.
Matthew said he owed his life to the coastguard, RNLI, the police and the staff at Ulster Hospital.
"They are all heroes," he said.
He added that he would not be surfing again.