It was the height of winter in 1917 when the steam tug Nyora sank during one of the worst storms experienced by sailors in South Australian waters.

Key points: Spectacular footage of Nyora is revealed 102 years after it sank in severe weather

Spectacular footage of Nyora is revealed 102 years after it sank in severe weather Its discoverer says it will provide an important record for future generations

Its discoverer says it will provide an important record for future generations 14 people died in the disaster off the coast of South Australia

The tug had been towing the American-masted motor sailing ship Astoria from Port Pirie to Sydney.

Nyora began listing — an imbalance eventually blamed on displaced coal supplies — after it spent a day-and-a-half ploughing through heavy seas.

When its engine room door was smashed in by a wave off Cape Jaffa, the captain, William McBain, gave the order to lower the lifeboats but the tug was listing too much.

The towline to Astoria was detached but Nyora still went down, taking with it 12 of the 16 crew.

The steam tug foundered in heavy seas on July 9, 1917. ( Supplied: State Library Victoria [1651623] )

Shipwreck sighted

Nearly a century later in 2014, the remains of the 41-metre vessel were sighted for the first time thanks to the unerring passion of Steve Saville, who researches, dives and discovers marine artefacts in his spare time.

It took Mr Saville three years to locate Nyora's location 50 kilometres offshore — utilising coordinates and bearings from survivors, the assistance of local fishermen, overseas geography experts and his own scanning of the ocean floor.

He found the wreck 50 metres below the surface, a depth at which he could only spend a few minutes before starting his decompression schedule.

"I have an interest in maritime history, particularly in relation to shipwrecks and fishing vessels lost in South Australia," he said.

"After doing research on the vessel, you draw a strong connection to it because you have a much greater understanding of not only the vessel, but the crew who worked the vessel as well."

Nyora rests 50 metres below the surface. ( Supplied: Steve Saville )

Following his initial dive, Mr Saville could not return for another four years due to "work, travel, finances and other exciting shipwreck projects".

But equipped with a gas trimix to enable longer bottom times, he embarked on a series of dives in December that were initially as "dark as night" at the bottom due to an upwelling event.

Then in February, favourable conditions returned and along with more dives over Easter, Mr Saville obtained clean footage to confirm the wreck was Nyora.

Adrift on a broken lifeboat

McBain was at the wheel with able seaman Gordon Lansley during Nyora's final moments and they were tossed into the sea as it sank.

The men managed to avoid being sucked down with the vessel and swam towards an engineer sitting on top of an upturned lifeboat.

When they righted the lifeboat they found the stem — the foremost part of the bow — had been ripped out, rendering the boat near inoperable.

The region has a reputation for large waves, such as these pictured at nearby Penguin Island in 1911. ( Supplied: State Library of SA [PRG 280/1/44/184] )

The trio pulled a fourth man, a fireman, out of the water, before using a plank to try and make their way to shore.

Crew from the crippled Astoria prepared to set its auxiliary sails and attempt a rescue, but they had their own difficulties in the storm and were unable to assist.

They attempted to alert a nearby merchant steamship, SS Tarcoola, but communication failed because Tarcoola was not fitted with a radio.

Astoria and its crew eventually sailed, slowly, for Guichen Bay south of Cape Jaffa to raise the alarm.

Rescued at last

The Nyora survivors rowed as best they could, but within two hours the fireman had died from exposure and slipped into the rough seas, followed by the engineer two hours later.

A steam vessel, City of Adelaide, was dispatched from Beachport upon hearing of the disaster but was significantly delayed because its engines failed.

A tug sent to rescue and salvage Nyora in 1917 recovered a bucket. ( Supplied: State Library of SA (PRG 280/1/3/252) )

Night fell and the stranded sailors took heart when they sighted the light from the Margaret Brock Reef lighthouse off Cape Jaffa about 7:30pm.

They rowed and drifted as best they could and by 8:30am the following day, two lightkeepers — John Jameson and his assistant Robert Thomas Clark — signalled to the survivors to keep their broken lifeboat away from the breakers and the reef below.

Jameson and Clark then risked their own lives to row out and rescue the men; the lightkeepers were awarded silver medals from the Royal Humane Society of Australasia for their efforts.

McBain and Lansley, the only survivors, were transported by cutter to Kingston.

The Cape Jaffa lighthouse was built atop Margaret Brock Reef. ( Supplied: State Library of South Australia )

A record for future generations

Mr Saville has written his findings, along with research into the disaster and the inquiries that followed, in a report that he said would be made available to relevant departments and marine archaeologists and ecologists.

"South Australia is extremely rich in maritime history because of our early trading, what we call the mosquito fleet, the ketches and schooners that plied the trade," he said.

"There were no roads or rail and that's how all the goods were moved."

The Port Pirie wharf was a busy place for ships in the early 1900s. ( Supplied: State Library of SA [B 10984] )

But despite this rich history, Mr Saville said he feared today's generation would be unlikely to take as much interest as others because they were "so busy with technology and everything else".

"My main motivation for doing what I do, in the filming, is not actually for today's generation," he said.

"It's for future generations, because they will be less able to access these type of locations, the shipwrecks, because they are deteriorating."

A popular tug

Before its sinking, Nyora was well known among the public and seafarers alike, Mr Saville said.

"The Nyora was a popular tug of Port Melbourne and would be called upon to solve all sorts of shipping problems around Australia," he said.

Nyora, pictured circa 1915, towing the Inverness-Shire. ( Supplied: Museums Victoria )

It had been requisitioned to help Astoria after the ship, which had recently arrived in Sydney from the US, suffered catastrophic engine failure near Gabo Island on its way to South Australia and had to return to Sydney.

The parts Astoria required had to be ordered from the US, so the vessel and its massive load of timber were towed by Nyora to Port Pirie, from where they would begin their fateful return journey.

"This is a remarkable story of tragedy, perseverance and heroism," Mr Saville said.