Amid pounding waves, the shoreline was littered with shiny pieces of coal for hundreds of metres after a fierce storm.

Locals quickly guessed that the remarkable sight didn't come from flooded deep-sea ocean tunnels beneath the sand and earlier Hunter River delta mining. It came from coal cargoes of old wooden colliers sunk in the bight many decades before.

These old shipwrecks, mostly timber, were assumed to have finally broken up with the undersea fury of the recent tempest.

Some of the "black diamonds" covering the shore would probably have come from the wreck of the paddle steamer Yarra Yarra sunk way out beyond the breakers in July 1877.

The once pioneer steamship had unsuccessfully attempted to return to the safety of Newcastle harbour in a gale with 500 tonnes of coal onboard before being sunk.

About 18 lives were lost. The sunken vessel now sits upright in 15 metres of water out in the bight and is a popular spot for recreation divers.

The coastal trader was once described as being one of the most intact paddlewheel steamers in Australia. And there are many other shipwreck gems, if you can find them, amid the constantly shifting sands of Stockton Bight.

Another highlight for scuba enthusiasts is a fellow paddle-wheeler, the tug PS Commodore, which was scuttled in 36 metres of water in September 1931 about six kilometres due east of Nobbys.

The wreck of the vessel, which was built in 1878 near Newcastle, in the United Kingdom, had rare side-lever engines but was severely damaged by a dragging ship's anchor about 1984. This came only weeks before keen scuba divers called on the federal government to protect the historic site.

At least 48 wrecks are estimated to litter Stockton Bight seafloor today, with as many as 50 more perhaps buried along Stockton beach itself over the past 200 years.

All this is very topical, with NSW geoscientists assembling a precise map of shipwrecks off Newcastle's coast during their search for a suitable sand source to replenish Stockton's rapidly disappearing beachfront.

As the Herald reported recently, this map data will be part of an extensive report soon to be tabled, advising on how to best tackle the suburb's beach erosion crisis.

Concerned Stockton residents believe that 10 million cubic metres of sand has disappeared in the area since 1887, including a landmark sandbank a kilometre offshore. This once acted as a buffer to big swells and during major storms, dissipating the energy of rogue waves.

Residents say this protective sand barrier once rose to within two metres of the surface, but the water there is now up 15 metres deep, giving the beach little protection from future big waves.

Surfers say that waves of up to 5.5 metres high occur at least once a year at Stockton. But during the huge storm that caused the grounding of the bulk carrier Sygna on the beach to Stockton's north in 1974, the swell reportedly topped 17 metres.

Much of the tidal sand changes have been blamed on the creation of Newcastle's twin ocean breakwaters, protecting the port, but interrupting currents carrying suspended sand north.

Since 1846, blocking this longshore drift has caused an extraordinary built-up of sand, actually creating today's Nobbys Beach from deep water.

All of which means that today there's a tremendous amount of sand swirling about in different ways in Stockton Bight.

Up on the North Coast, coastal storms in 2009 suddenly uncovered five shipwrecks, but the sites of most of Stockton's shipwrecks are already reasonably well known.

Enough sand has already been scoured within the bight for marine archaeologists to positively identify at least eight major wrecks, including the PS Commodore.

So, possibly expect no big surprises from the latest, official shipwreck map.

Best known among the bight shipwrecks are the Berbice, a British cargo ship which foundered off Stockton Beach in July 1888. Finally emerging from its sandy tomb in 2018, it has a debris field about 40 metres long.

Then there's SV Durisdeer, a three-masted iron barque, which ran aground on Stockton Beach on December 22, 1895. It's about 500 metres north of the Berbice. Both vessels are in about five metres of water offshore.

Next comes the Yarra Yarra from 1877 and the SS Davenport, a US ship once carrying war munitions that caught fire in harbour in October 1943. It was then towed into the bight.

The fire-ravaged ship soon sank in 12 metres of water in front of the Stockton Surf Club.

Other found vessels include the 1883 tugboat Irresistible that was scuttled in the bight also in 1931 and lies upright 26 metres down on sand.

Then there's the SS Osprey. Built in 1885, it's also sitting upright on sand but 42 metres down.

Over the years, scuba divers and trawler crews have dragged up a wealth of bight shipwreck objects, ranging from anchors, to portholes, parts of ship rudders, to three mystery pre-1850s cannons buried in sand.

The single, oddest find, however, is probably the tail shaft and two wheels of a six-wheel army "duck", or DUKW, found entangled in the net of a trawler off Stockton Beach in April 1974.

This capsized amphibious vehicle, found in about 27 metres of water, was a relic from the Stockton Bight military disaster of 1954. It was one of eight amphibious vehicles that simply disappeared, sunk, when a sudden squall struck a pre-dawn army convoy heading towards Morna Point from Horseshoe Beach.

About 100 soldiers were pitched into freak heavy seas infested with sharks. Two men died and a third was declared missing. It was one of Australia's worst peacetime disasters.

The full story is told in my latest book, The Hidden Hunter ($40). Another sequel to this tragic tale came around 1987, or earlier, with a discovery way up the bight by scuba divers. This find also came from the same ill-fated military exercise and was a lost, barnacle-encrusted amphibious army tank, or LTV (A)4, swarming with fish life.

Live ammunition is still visible on the tank turret about 33 metres down on the sand. The other four missing tanks have never been found - officially, at least.

The incident has never been forgotten, and is even commemorated on a special wall that was erected in parkland in 1988 at the former Camp Shortland base, near Nobbys Beach. The monument also features a ship anchor similar to those once discovered in Stockton Bight.

Meanwhile, some mysteries remain. Like why are there strange pyramids of stone, often hidden by sand and covered in fishing nets, in Stockton Bight?

But that's a tale for another day.

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