by Bob Wonders
The vessel was described as an 11.0-metre Halvorsen that had only recently been purchased second-hand by the owner.
Melbourne Fire Brigade Commander Wayne Garrad told the Herald Sun the boat had exploded after repeated attempts to start the engine.
The dead are believed to be a couple in their sixties, parents of the boat’s owner, a 48-year-old man.
His partner, 45, is said to be in critical condition.
Four others, a woman and her three sons, aged 13, 11 and five, were standing on the fuel dock and received minor injuries; they were taken to hospital for observation.
Commander Garrad said the vessel was “totally destroyed.”
He said wreckage had been scattered 30 to 50 metres from the dock.
Inspector Steve Guilmartin, of the Victorian Water Police, said statements were being gathered from witnesses and security television footage was being closely examined.
“A water police sonar team is also taking images of the river bed beneath the dock, as well as what remains of the vessel’s hull, in an attempt to discover the sequence of events,” Inspector Guilmartin told the Herald Sun.
“It’s particularly important we can determine the cause in order to minimise the risk of this happening again,” he added.
The fuelling dock at Melbourne’s popular Pier 35 was significantly damaged in the explosion.
Water police and arson squad detectives continue to closely examine the site and all details connected with the tragedy.