Acoronial inquest has found three members of a South East family from Keilira died as a result of exposure to the sea more than five years ago.
Annette and Len Vandepeer, both 56 and their son Douglas, 27, went missing in the Southern Ocean off Cape Jaffa on December 12, 2016.
The seven-metre aluminium boat they were on board has never been found, but is presumed to have sunk.
Deputy State Corner Anthony Schapel handed down his written findings in Adelaide on Thursday.
Mr Schapel had examined bank, phone and medical records but found nothing to contradict the belief they had died at sea.
“There is no evidence to suggest the disappearance or deaths of the Vandepeers were in any way suspicious,” Mr Schapel said.
“In my view it is highly likely the event that caused it to sink was sudden and unexpected and did not provide any opportunity for the Vandepeers to activate the EPIRB (emergency beacon) or to use a radio or mobile phone as a means of communication.
“As to why the boat has never been found can only be the subject of speculation.
“Police have maintained contact with the surviving members of the Vandepeer family and have received no information that would suggest that Len, Annette or Douglas were alive at any time after December 12. 2016.”
A number of items from the boat were later found washed up on a beach north of Kingston.
