IT TOOK less than three hours for a 40ft ex-trawler to go from the surface to the bottom of the Yamba Harbour this morning.
The question that hasn't been answered yet is why.
Roads and Maritime Services boating safety officer Luke Tucker said the speed that the wooden vessel, now a privately-owned recreational vehicle, sunk at could offer some clues to the cause.
"At sunrise she was high and dry, by 9.30am she was on the bottom," he said.
"Usually it's what they called a sprung plank in this type of situation, where a board on the boat fails and sudden rush of water the pumps can't keep up.
"Or it could be as simple as what's called a skin fitting, where a fitting through hull fails and the little pipe behind just leaks and leaks."
Whatever is behind it, it doesn't change the fact the boat will have to be salvaged.
The owner is aware of the incident, and is understood to be fairly devastated.
A small amount of diesel fuel leaking has been contained by a boom, set up by RMS and NSW Fire and Rescue personnel.
Update your news preferences and get the latest news delivered to your inbox.