In January 1997, Tony Bullimore was trapped inside an upturned yacht that was filling up with "bitterly cold" water in one of the remotest parts of the Southern Ocean. In History looks back at an incredible feat of survival, and an amazing rescue.

British sailor Tony Bullimore had just made himself a cup of tea and was settling down to eat some crackers and corned beef in the galley of his racing boat, the Exide Challenger, when he heard the sound of a crack. "The snap was like a match," he said in a BBC documentary in 1997. That sound was the keel – the flat blade on the yacht's bottom that kept it right-side up – snapping off. It was then that all hell broke loose. "The yacht turned over in literally a few seconds – three, four, five seconds, the yacht was upside down. I mean, it was as quick as that."

As the boat rolled over, Bullimore was catapulted out of his seat, somersaulting and landing feet first on the inside of the roof of the yacht's galley. "The amazing thing was, I was standing all of a sudden on the roof, inside on the roof of the yacht. The roof was now the bottom of the hull. And I've got these very big viewing windows and I'm looking down into the sea."

It was then that Bullimore realised just how much trouble he was in. "When I looked down into the windows, I noticed that the boom from the foremast was slamming up against one of the windows because it was now loose, but it was hanging in there because the ropes were holding it in place." The solid carbon-fibre pole was being rammed repeatedly against the window like a sledgehammer by the motion of the storm waves. "Within about half an hour, it smashed the window. And the water came in the boat like the Niagara Falls upside down," he said. As freezing water poured into the hull, it fused the electrics – plunging Bullimore and the whole vessel into darkness. "Once the window went, that really put me into a different league of problems," he told the BBC with characteristic understatement.

The 57-year-old sailor from Bristol, England had been competing in the Vendée Globe, a gruelling non-stop singlehanded around-the-world yacht race. It is considered by many to be the world's toughest sailing race, but Bullimore was a seasoned yachtsman. As the race took the competitors eastwards into the Southern Ocean towards Australia, a violent storm struck, and the Exide Challenger was battered by ferocious waves and winds of up to 100mph (160km/h).

"You look in front of you and think it's an iceberg, you see this enormous mountain [of water], it could be up to 60, 70, 80ft (25m) high, and you can't believe it," Bullimore said. "Apart from the wave breaking forward, you get a split wave where it's breaking backwards as well, like a tumultuous mountain of water. It's really quite incredible. The power behind some of those waves, I mean, you are talking about several double-decker buses chucked in together."

He had battled this wild and unforgiving storm for several hours and, believing that he had his yacht under control and all the hatches battened down, he was "feeling pretty pleased" with himself. When the boat then suddenly flipped over, initially he couldn't believe what had happened. "I probably said to myself, 'I don't believe that the keel's snapped off,' a couple of dozen times, but it had," he told the BBC. "I was shocked, but I'm a pretty steady guy. I don't panic."

With the viewing window now broken and the upturned hull rapidly filling up, Bullimore fought his way through the "bitterly cold" rising seawater to get his insulated waterproof survival suit, stripped off his sodden clothes and put it on. Despite the sea rushing in, The Exide Challenger didn't immediately sink. This was because its bulkheads, which divided the ship into smaller watertight compartments, were helping keep it afloat. The water stopped rising just below Bullimore's neckline but it now formed waves inside the boat that were pitching from side-to-side, as the squall pounded the Exide Challenger from the outside. "You could see the seas that were inside the hull smashing up against one side, then rolling and churning up and then rolling to the other side of the yacht. It was like the inside of a washing machine," he said.

The smashed window and the boat's motion were creating a powerful vacuum effect, pulling everything – food, charts, equipment – out through the hole. "It was unbelievable, it just kept ripping things out. Food in plastic boxes that was lashed down, once the lashings got loose, the boxes just flew out." Bullimore found one of his emergency beacons, tied it to a piece of rope, dived down and pushed it through the broken window, hoping it would float to the ocean surface and someone would pick up its distress transmission.

Although the Exide Challenger was afloat for now, he knew that if the capsized yacht's watertight bulkheads........

© BBC