SYDNEY (AFP) - A yacht has been found drifting off the Australian coast with computers running and a table laid for a meal -- but no sign of the crew, puzzled officials said Friday. The 12-metre catamaran was spotted by a customs helicopter about 80 nautical miles off Townsville on Australia's northeast coast, near the outer Great Barrier Reef on Thursday, national radio reported. The discovery that the yacht was unmanned sparked a major sea and air search for the three crew, two men in their 60s and one aged 56. Emergency Management Queensland spokesman Jon Hall said rescue crews were puzzled by what they found aboard the yacht because "everything appeared normal". "The engine was running, the computers were running, there was a laptop set up on the table which was running, the radio was working, the GPS was working and there was food and utensils set on the table ready to eat, but no sign of the crew," he said. "It was a bit strange." Police said one of the crewmen is believed to have bought the catamaran, KAZ II, at Airlie Beach south of Townsville and the three planned to travel home to Western Australia around the northern coastline. Hall said the boat's GPS system had been retrieved and the data would be analysed for clues to the mysterious disappearance of the crew. "That will now enable us to track backwards where this yacht has actually been in the last few days, and we're hoping that can pinpoint the search area for the missing crew," he said. All the boat's sails were up but one was badly shredded, while three life jackets and survival equipment, including an emergency beacon, were found on board. Police Chief Superintendent Roy Wall said there was nothing to indicate the yacht had capsized at any stage. "There's nothing on board to indicate there's been any great disaster. The vessel is upright and certainly in reasonably good condition. "At this stage it's just a mystery." Water police were towing the yacht to Townsville, where it would be subjected to a forensic examination, Wall said. "The weather on Sunday, Monday wasn't too good -- there was a fair sort of a wind blowing out there. But it's improved since then, so who knows what could have happened."