Sky News UK reports that the bottle was found on a beach in New Zealand by Geoff Flood in November 2012, but had been set adrift in 1936.
Inside was a note, dated March 17, which said: "At sea. Would the finder of this bottle kindly forward this note...to undermentioned address."
Mr Hillbrick had died in the 1940s, but further investigation led Mr Flood to Herbert's grandson Peter Hillbrick, who was living in Perth.
"The only connection I have with Grandfather is now that bottle. That's about all. So, it's a fascinating story," he said.
Video in link.