Three friends who drowned on a daytime boating trip had earlier been drinking and taking drugs, and should not have been on the water, a coroner has found.
Isaiah Dixon, Bree-Anna Thomas and Thomas Courto set off from Wynyard in northwest Tasmania around 10am on October 18, 2021.
A large-scale search was sparked around seven hours later when police were told the five-metre white and yellow fibreglass motorboat was overdue.
The bodies of Mr Dixon, 23, and Ms Thomas, 31, were found washed ashore two days later.
Remains belonging to Mr Courto, 27, were discovered in April 2022 by a recreational diver, while the boat has never been recovered.
Coroner Simon Cooper said it was difficult to avoid the conclusion a combination of alcohol, illicit drugs and a failure to take basic safety precautions caused their deaths.
None of the trio were wearing life jackets and all were affected by alcohol, methylamphetamine and fatigue.
"Having regard to the evidence as a whole it is my firm opinion (they) should not have been on the water that day," Mr Cooper said in findings published on Tuesday.
He said it was impossible to determine why the boat sank but the most likely explanation was a mishap as a result of drug or alcohol impairment.
"The tragedy was wholly avoidable," Mr Cooper said.
The group had been drinking until at least 4am the night beforehand and bought six four packs of vodka cruisers and a 10 pack of cider in the morning to take with them.
Mr Dixon told a fishing shop worker they were going on a "fun drinking trip".
The same worker said Mr Dixon looked drug or alcohol-affected and appeared to lack boating experience because he asked a question about fuel ratios.
Another witness thought the trio were "very intoxicated" the morning they left.
The last contact made by the group was from a social media video posted by Mr Dixon which showed him on the boat without a life jacket.
Mr Cooper said if the trio had been wearing personal flotation devices they would have likely all survived.
Autopsies revealed Mr Dixon and Ms Thomas had methylamphetamine in their system.
Mr Dixon had a blood-alcohol level of 0.110g per 100ml - above the legal limit for operating a non-commercial boat.
Mr Dixon held a motorboat licence and borrowed the vessel from his father, who said his son was experienced and familiar with Bass Strait near Wynyard.
Mr Cooper said there was no evidence adverse weather conditions, the lack of a seaworthy boat or actions of a third party contributed to their deaths.
Mr Dixon's father said the boat had a radio, navigation lights, life jackets, oars, flares, a fire extinguisher and an anchor.
