WHEN Peter Manderson heard his boat propeller jam on the Fitzroy River, he thought it was a piece of wood causing the trouble.
But when he went to look, he found a stingray stuck between the propeller and rudder post of his 46ft (14m) boat, King Cnut.
"It made a hell of a bang (when it hit)," he said.
Peter was 10kms downstream from Nerimbera boat ramp on Sunday when the stingray became caught.
It took some effort to find out what it was, Peter said.
"It wasn't even that big, only about 10kg, but still enough to jam the propeller.
The coast guard was called, but due to their flotilla undergoing repairs, they couldn't get the stranded boat back to shore until Tuesday.
Peter said he'd never heard of a stingray causing this sort of trouble.