Elliot said he was looking for the author Paul Gibson, who described himself in the note as a 13-year-old English boy traveling in a cruise ship along the southern Australian coast from Fremantle in the west to Melbourne in the east.
Government oceanographer David Griffin said the bottle could not have remained afloat for 50 years off the south coast because "the ocean never stays still."
Griffin suspected that the bottle had been buried on a beach for years then refloated by a storm.
"If it had been dropped in anywhere in the ocean somewhere south of Australia, then there's no way it's going to stay actually at sea moving around for more than a year or two," Griffin said.
The author gave his position as "1000 miles east of Fremantle." However it is not clear whether the author actually meant 1,600 kilometers (1,000 miles) out of Fremantle, which would have included a journey south along the west coast before turning east.
Hundreds of thousands of Britons migrated to Australia in the 1960s with the Australian government subsidizing their fares. Children traveled for free.
But a quarter of them returned to Britain within a few years when life in Australia fell short of their expectations.