Friends of a Wigan businesman desperately tried to save him after he fell ill during a sailing holiday in Greece, an inquest heard.
David Avery, of Liverpool Road, Ashton, went to lie down after feeling unwell on the boat.
But friends noticed his lips were blue and he felt clammy a short time later.
They could not rouse him and performed CPR, but despite their efforts - and those of a doctor who later got on board - Mr Avery died.
An inquest at Bolton Coroner’s Court yesterday heard the 61-year-old dad enjoyed sailing and regularly went on trips with friends.
A nine-strong group hired a boat in May to spend a week sailing around Greek islands, with his friend George Dowler as the skipper.
Most of the group, including Mr Avery, flew to Greece on May 19 and the boat set sail on May 21.
Mr Dowler, who had been friends with Mr Avery since they were 16 and was his partner in Ashton-based business Blastclean, said he was making jokes on the boat.
But about 30 minutes later, he said he felt “whizzy” - used to mean dizzy - and he went to lie down.
The inquest was told Mr Avery could be heard snoring, but then one of the men on board became concerned about him, noting his lips had turned blue.
The men could not wake him so started doing CPR, while others radioed for help and consulted maps for the nearest port.
The police and medics were waiting when they arrived at the port, but Mr Avery could not be revived.
The inquest heard Mr Avery was sometimes known as a hypochondriac, but seemed well before the trip.
Mr Dowler said: “If any of us had said we didn’t feel well, we wouldn’t have set off for port but everything was fine.”
His partner of nine years, Lisa Maria Bligh, said Mr Avery had been looking forward to the trip and she had no concerns about his health.
A post-mortem examination was carried out by Dr Naveen Sharma at Whiston Hospital, though he told the inquest it was clear an examination had previously been done in Greece.
He recorded the cause of Mr Avery’s death as pulmonary oedema - a build-up of fluid in the lungs.
He explained it may have been due to cardiac failure, but he could not be sure as he did not examine Mr Avery’s heart.
He also said it was “difficult” to say whether Mr Avery would have survived if he had fallen ill on land and seen by a doctor sooner.
Coroner John Pollard said: “He has clearly had some sort of cardiac/lung event.
“The only conclusion I could possibly reach is that he has died of natural causes.”