WHEN Hayman Island State School principal Rohan Robertson found a mystery aircraft motor in the shallows off a Whitsunday island late last year, he was keen to uncover the story behind it.

Mr Robertson contacted the Great Barrier Reef Marine Park Authority (GBRMPA) and Royal Australian Air Force (RAAF) in the hope of identifying what appeared to be the engine from a bomber or Catalina dating back to the Second World War.

The Whitsunday Times also ran a story on the find (December 18, 2014), which was read by local historian Ray Blackwood.

Mr Blackwood instantly recognised the motor as belonging to a Catalina that serviced Hayman Island and sank inexplicably more than half a century ago.

The woman with the full story is 85-year-old widow Joyce O'Hara.

Mrs O'Hara's husband Vic was a private pilot who often admired this Catalina, then called the 'Golden Islander'.

"It went through his mind that the hull of that Catalina would make a beautiful boat," Mrs O'Hara said.

Both Mrs O'Hara and Mr Blackwood recall the plane sinking on its mooring at Hayman Island, after which it was towed to the Langford Island spit.

Mrs O'Hara said her husband was eventually able to buy it from its former captain and on Friday, September 14, 1962, he and six or seven men from Proserpine "went out there with trees and 44-gallon drums and made a sort of raft and re-floated [it]".

"And that's when they cut the motors off," she said.

The Catalina was brought back to Shute Harbour and towed by four-wheel-drive to Hamilton Plains where the O'Hara's lived.

Mr O'Hara turned its hull into a boat called the Henrietta Ho, which after years of use as a family pleasure cruiser was eventually sold to a man from Home Hill.

"And he took it to pieces and sold the motors and it's no more," she said.

Vic O'Hara passed away in February 2014, aged 88, but the story of Mr Robertson's mystery motor has now been revealed.