Bryn Watkins had been sailing alone before he was found dead last October near his yacht Athena 2 in Kames Bay on the Isle of Bute by a fisherman.
A post mortem found the cause of death was drowning and Mr Watkins, from Cleobury Mortimer, also had signs of hypothermia.
The 74-year-old retired auditor and train guard was a well known member of Bartley Green and Dudley Sailing Clubs in recent years.
Worcestershire Assistant Coroner James Puzey recorded a verdict of accidental death noting: "It is unclear how he came to be in the water."
The father-of-three was in contact with his wife throughout his voyage, which was the last of the season, until his last phone call when he told her "not to worry".
Sergeant Christopher Dibbs, based at Rothesay Police Station, confirmed life jacket had not inflated. His body was discovered at 8am but local fishermen believe his boat had been in the bay since 2am.
His wife had begun ringing the coastguard after 10pm on October 18 last year after beginning to worry her husband might have got into difficulties on his own.
John Field, who investigated the incident, believes Mr Watkins fell into the water whilst trying to attach a rope onto a buoy, and the shock of the cold water might have meant he was unable to inflate his lifejacket.
In a tribute to Mr Watkins, a Bartley Green Sailing Club spokesperson said: "It is with sadness that we informed members of the passing of one of our former Commodores Bryn Watkins at the age of 74.
"Bryn sailed a Supernova at the club and was Commodore from 1997 to 1998."