Dire warnings over wreck of the RMS Niagara off Northland coastby Lois Williams
There are fears the hull - holding back 1500 tonnes of oil - could finally implode.
The RMS Niagara, sunk by German mines 77 years ago, has been leaking oil ever since, and fears are growing that the wreck could suddenly collapse.
The once-stately ocean liner lies on her side, some 120m deep, in the shipping channels between the Hen and Chicken and Mokohinau Islands, off Whangarei's Bream Head.
On the night of 19 June 1940, she was on her way from Auckland to Vancouver with passengers and a top-secret cargo of gold bars - payment by the UK government for American munitions.
A mine - one of 228 placed a week before by the German naval cruiser Orion in a bid to blockade the Port of Auckland - blew a large hole in her bows. The passengers were saved and most of the gold was salvaged.
Author and underwater explorer Keith Gordon and others have warned a ticking ecological time-bomb still lies unexploded in her bunkers.
Mr Gordon, who once owned salvage rights to the wreck, said it had been belching oil since he first explored it in the 1980s.
"Even sitting [in a boat] over the wreck, there was always a strong smell of oil coming up around us," he said.
"We were based out at Tutukaka, and sometimes going out to the wreck we would find oil slicks. I remember one, it was about 15 kilometres long, coming from the wreck."
The oil rose up in tennis-ball sized blobs, probably from popped and corroded rivets, Mr Gordon speculated.
He feared the time was coming when the hull of the Niagara would finally implode, and a huge quantity of oil would be released into the seas off Northland and Auckland.
Maritime New Zealand has said in the past it did not know what how much oil was still in the Niagara's bunkers, but it was highly unlikely there would be any significant release.
It said there were large oil spills at the time of the sinking, and later during salvage operations.
Mr Gordon said that by his reckoning, even allowing for the spills, the Niagara still had about 1500 tonnes of heavy oil on board in bunkers that had so far held their own against the sea.
Year by year, the wreck was breaking down, he said.
"As well as the corrosion of the metals, it's biologically imploding - there's a bacteria that actually eats away at the iron. So, structurally, the ship in time loses its strength and it will suddenly collapse.
"It's not sitting upright and ships are not designed to be in that position."
Mr Gordon and a team of supporters asked this month for the Auckland and Northland Conservation Boards to back a plan for a high-tech survey of the Niagara.
Mr Gordon's associate Clive Sharp, a former Hong-Kong-based operations manager of a company specialising in underwater inspection and salvage, said modern remote-controlled submarines now used ultrasound to test the strength of a hull - and could even determine how much oil was inside.
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