The families of three men who disappeared from the "ghost yacht" found floating off the Great Barrier Reef have called off their search, a spokesperson said Monday.

There has been no sign of skipper Derek Batten, 56, Peter Tunstead, 69, and his brother James Tunstead, 63, since the Kaz II was spotted drifting off the northeastern Australian coast in late April with its sails up, engines running and food on the table.

Police suspect the menwere swept overboard in rough weather during their planned two-month trip around Australia's northern coast.

The official search was called off on April 22, but the families said they planned to continue their search. They spent tens of thousands of dollars hiring planes, helicopters and boats to scour nearby islands.

Family spokesperson Glenn Tunstead said the family felt a "sense of failure" because they haven't found the men.

"It was very emotional for everybody involved," he told Australian Broadcasting Corp. radio.

"There was a sense of failure (but) on the other hand it was a sense of they did everything they possibly could and we didn't achieve the outcome that we wanted."

The catamaran, nearly 10 metres in length, was found about 150 kilometres east of the city of Townsville on the northeastern coast of Australia. Life-jackets, along with a dinghy, were found on board.

Forensic examiners in the nearby city of Townsville didn't find any clues on board the ship.

With files from the Australian Broadcasting Corporation