Officials with Australia's marine police are puzzled by the discovery of an unmanned yacht found floating off Australia's Great Barrier Reef with its engines and electronics running, and food served on the table. The catamaran, named Kaz II, was spotted by a coastal aircraft during a regular patrol on Wednesday, but it was on Friday that rescue workers boarded the boat and reported the missing crew.

Emergency Management Queensland spokesperson Jon Hall said that when rescuers reached the yacht they found the computers on the boat running and a table that apparently had been freshly set for a meal - but there was no signs of the crew.

According to AP reports, Hall said, Radio communication devices on the boat were also working and there was no indication of any damage except for a "shredded" headsail.

The strange discovery has sparked a massive sea and air search for the three crew members - Australians aged 56, 63 and 69 - who are believed to have set sail for the north-eastern city of Townsville from Airlie Beach in Queensland State on Sunday.

Three life jackets and the vessel's emergency beacon were found on board.