Charles Frederick Price was 40 years old, had a wife and three children, and was a working mechanic when he launched his 20-foot boat off Oyster Cove en route to Dover, but his family never saw him again.

Coroner Simon Cooper, after investigating the circumstances surrounding Mr Price's disappearance, concluded he was dead and likely drowned, possibly when trying to detangle nets that had ensnared his propellor.

"The propeller of Mr Price's boat was found with part of a graball net wrapped around it. This may suggest that Mr Price had some difficulty setting (or retrieving) a fishing net and perhaps entered the water as a consequence of the difficulty - it is impossible to say," Mr Cooper wrote.

IN OTHER NEWS:

Mr Cooper wrote the boat had been found during extensive ground and sea searches by police in the D'Entrecasteaux Channel near Middleton.

Upon finding the boat, Mr Price was not on board and there was no evidence to suggest he had met with foul play, or that any other person was on board the boat.

Despite an unsubstantiated sighting of Mr Price some years after his death by a family member in Victoria, Mr Cooped found Mr Price was never seen or heard from after December 23, 1978.

Mr Price had not held a bank account, registered with Medicare or Centrelink, bought a house or car, voted or been issued a passport.

The investigation left Mr Cooper to conclude Mr Price died "on or shortly after 23 December 1978".

"I suspect that the cause of his death was drowning. I think it likely that he entered the water, accidentally, perhaps retrieving a fishing net, and was unable to recover himself," Mr Cooper wrote.