DOUGLAS HISLOP is a reluctant hero despite his actions preventing a partially submerged 300- metre walkway weighing more than 1000 tonnes from crashing into Brisbane's Gateway Bridge.

He was listening to the radio at about 4am when he heard a report that the walkway had broken loose up river. "I knew it could cause a big problem as I had helped put it there … it's a massive thing," he said.

Hero ... Douglas Hislop. Credit:Jason South

Mr Hislop, 65, fired up the 8000-horsepower engine on his 50-foot tug, Mavis, at the base of his Bowen Tug and Barge company near Brisbane Port and chugged up river against the raging torrent.

Twenty minutes later he reached the walkway about half a kilometre away from the bridge, just as it appeared to be heading for the pylons. Police had closed the bridge, fearing the impact would badly damage the bridge or even cause it to collapse.