Searchers on Tuesday failed to find any further trace of the small, ageing runabout which launched on Sunday from a beach at Cremorne and failed to return as planned hours later.
On board were three Hobart men aged 26, 32 and 33, and a 35-year-old New Zealander, embarking on a fishing trip.
Two bodies found on Monday are yet to be formally identified while investigators try to determine if other items – a fuel tank, life jacket and tackle box – found in the search area are connected to the missing 4.9-metre fibreglass craft.
Water police Inspector Lee Renshaw held little hope that the remaining pair would be found alive.
“Based on the technical data we use to determine survivability rates, based on the sea conditions and the temperature of the water, it is highly unlikely that anyone could survive,” he told reporters.
Hobart woman Alexandra Hayes told The Australian newspaper her partner Magnus Ritter, a personal trainer, was one of the four men.
She said the incident highlights the importance of taking proper precautions on the water.
“Safety is paramount and someone experienced should always be aboard,” Ms Hayes told The Australian.
“I’m now finding it hard to contemplate life without him. There is not much hope left.”
Nevertheless, searches by land and water of sea, beaches and cliffs will continue.
Police are using drift patterns and mobile phone records to try and pinpoint where the 1970s model boat is likely to have struck trouble, and subsequently send down divers.
“We’ve done considerable work with Telstra and the Australian Maritime Safety Authority … and what we can work out on some pretty difficult mathematical equations involving telephones, we’ve now got a rough location,” Insp Renshaw said.
One of the two bodies recovered was wearing a life jacket and had suffered a head injury, police Commander Tony Cerritelli said.
“That will form part of that coronial inquiry,” he added, without speculating on what might have caused the wound.
The age of the craft means it would not have been fitted with flotation aids, compulsory in the construction of newer boats.
“That particular boat, had it been swamped with water, with four people on it, and with the motor the size it had on it – 150hp – it would have gone to the bottom,” Insp Renshaw said.
Winds on Sunday reached a maximum of about 15 knots on the water which the senior officer wouldn’t expect to have caused trouble manoeuvring the boat.
“We haven’t interviewed family members as to what experience these people had with the vessel, what experience they had as seamen, and what experience they had in driving and managing other boats.”
The boat had been purchased recently and one of the joint owners was aboard for the fishing trip. Search efforts are likely to be suspended overnight and will resume at daylight on Wednesday.