As his boat drifted towards the rocks, Mr Hendron grabbed his passport and money and jumped into a liferaft.
Richard Hendron was on a solo adventure in the 34ft Spirit of Daedalus when the seas around the Bay of Biscay took a dramatic turn for the worse.
Speaking to reporters, Mr Hendron, 38, from London said: 'I really thought my time was up and I am very fortunate to have escaped with just a few bruises.'
He had left the Spanish port of A'coruna at dawn and travelled for 20 miles when the seas suddenly changed.
He said: 'I don't usually clip myself in the cockpit but for some reason I did when I left the port. The weather was good, but it just changed and suddenly I could see these huge waves.
'They looked as big as a football stadium, and then one of them just crashed down on the yacht causing it to capsize.
'I have never seen such a huge wall of water. It was terrifying. I really thought I was going to drown
'For 30 seconds it felt like being in a washing machine. Finally it rolled back up with me still clipped in.'
In a vivid Facebook post written just after his rescue, Mr Hendron described the situation he faced: 'The boat is now a scene of utter carnage, sails ripped, solar panels torn off, Kayak snapped in two halves, water tanks from the saloon have been ripped out and the boat is four feet deep of water inside.'
Worse still, he appeared to be heading for a large collection of rocks with no engine, no sail, and no communication.
After attempting a mayday call he wrote: 'I have no idea if emergency signal went though. I can't just sit back and be rescued as I do not know if anyone is coming – besides I don't have long before the yacht could be ploughing into the rocks.
'If the yacht hits the rocks it will be too late for me to jump in life raft it will be no good to me, the yacht, life raft and I would be smashed into rocks. Do I risk it and abandon ship in hope that I might be able to have some control over steering of life raft or do I stay put those were my options – Do or die!'
He reluctantly concluded he had to abandon shop so he grabbed his passport, money and a knife, jumped into the raft and cut the line.
'I paddled frantically, draw stroking,' he wrote. 'The waves kept on coming. At one point I was flattened by a breaking wave on top, it was like being vac packed - but it soon pops up again and I kept on paddling.
'I miss the first set of rocks then the second set of rocks and third set of rocks and so on until eventually an hour and a half later I am clear of all the rocks and now in the middle of some big bay.'
Unbeknown to Mr Hendron, the emergency call he had made had gone through to the coastguard but was delayed by over an hour due to the rocks blocking the signal.
He was eventually spotted by a helicopter and a rescue diver jumped down from a Sea King helicopter to winch him to safety.
'Unfortunately I wasn't insured but I am just happy to be alive,' he told MailOnline.
'We flew back to the coastguard station and they were just great. They said most people they usually rescue have to go to hospital, but I only had a few bruises so we all had lunch. I owe them a debt of gratitude.'
Mr Hendron made headlines when he defended his brother Henry, a celebrity barrister, who was arrested in 2015 for supplying 'chemsex' drugs to his teenage boyfriend who died from an overdose.