He will forever be remembered as the hero tug boat captain who could well have saved the Gateway Bridges from disaster during the 2011 Brisbane flood.

Now, the late Peter Fenton has been honoured in a permanent underwater memorial, attached to the sunken barge on which he lost his life.

Mr Fenton, 67, died 11 months after he made world headlines with his maritime heroics when he was crushed to death by a crate that fell on top of him on board the MDT 7 barge.

Months earlier, Mr Fenton prevented potential disaster on the Brisbane River when he and colleague Doug Hislop successfully steered a dislodged 200-metre section of the Brisbane Riverwalk clear of the Gateway Bridge.