FUNNY how the past can sometimes continue to haunt us, isn't it?
Take the discovery recently on the sands of Nine Mile Beach at Blacksmiths.
Here, a strange, bulky, rust-red object suddenly came to light, puzzling surfers. It was thought to be part of an old steam boiler from the iron paddle-steamer Lowestoft swamped by heavy seas, then beached in 1864 only to break in half.
Then there's the strange find at Birubi Beach up at Port Stephens back in late 2014.
In this case, a long-lost aviation secret came to light.
Does an historic, once abandoned sailing ship lie undiscovered after sinking in the Hunter River at Morpeth 179 years ago?
Shifting sands revealed what at first looked like the wreckage of an entire RAAF aircraft from maybe the 1950s. A metal frame and exposed wing then led people to believe it might have been part of a Sabre jet which had crashed on the beach in February 1960.
Parks and Wildlife officers on the scene, however, came to another conclusion. They believed the aircraft may have been deliberately planted there for target practice around the end of World War II.
And believe it or not, that remote section of beach had indeed once been used by Williamtown RAAF fighter pilots as a bombing range!
Newcastle scuba diving pioneers also knew this to be true. When materials were still in short supply after WWII, they'd scavenged there for hard-to-obtain parts from the aluminium aircraft relics.
Of course, where wrecks are concerned, there's also something bigger and better. The next case concerns a major "lost" ship with a lot of history and strong links with Lake Macquarie. It's the former famous sleek and speedy passenger clipper called Sobraon.
One of her claims to fame was her having the largest composite hull (teak planking over an iron frame) ever built for a sailing vessel.
Built in Scotland in 1866, the large (2131 ton) sailing ship had an overall length of 317 feet (97 metres) and on its maiden voyage to Australia, she was described as the largest ship at that time to enter Sydney Harbour.
And here she is (pictured) floating high and empty and impressive, towering over Sydney's west Circular Quay in February 1871 at the height of her career as a people carrier.
When retired, the passenger clipper then became a nautical school ship (1891-1911) for NSW's colonial government to keep gangs of delinquent and vagrant boys away from moral danger on city streets and also to learn a trade to become employable.
The old Sobraon never went to sea again and was instead was moored off Sydney's Cockatoo Island.
Later, the ship was renamed HMAS Tingira (an Aboriginal word meaning "open sea") a name familiar today to people who know the Lake Macquarie suburb.
(Originally called Violet Town, the local progress association accepted the suburban name change suggested by members of the HMAS Tingira Old Boys Association after it was realised another Violet Town already existed in Victoria.)
The third stage of the old ship's career had begun when the Commonwealth Government stepped in to take over Sobraon for use as a naval training ship, renaming her HMAS Tingira and moving the ship to Rose Bay in 1912.
With her topmasts gone and repainted a stark white, the moored ship was a very visible landmark for many years for Sydney commuters.
The good ship Tingira is mostly only remembered these days for training thousands of young sailors for the infant Royal Australian Navy (RAN) until she was finally decommissioned in 1927.
From luxury clipper to floating reformatory, then as the RAN's first training vessel, the Tingira/Sobraon had a busy 61-year lifespan before going to the ship breakers' yard and into oblivion.
Or did she?
A shipwright bought Tingira in 1929 and towed her to Berrys Bay near the inner Sydney suburb of Waverton. She appears to have been run ashore in the early 1940s when a salvage crew began dismantling her. The sight from afar of her gaunt metal ribs was a sad reminder of Tingira's glory days.
But did the vessel ever leave Berrys Bay? Early research by the Australian National Maritime Museum's marine archaeology section suggests much of the forlorn shell of Tingira may today still lie buried beneath the water's edge of the (now reclaimed) Waverton Park.
And now to another ongoing mystery. Does an historic, once abandoned sailing ship lie undiscovered after sinking in the Hunter River at Morpeth 179 years ago?
If so, is anyone interested in finding her? Well, both answers are yes. The latest attempt began last September and research is ongoing.
Her name was St Michael and one reason for the great difficulty in locating this former store ship is that she's probably long buried in a private paddock at Phoenix Park. The St Michael may have been pushed into an inlet in the high riverbank opposite the historic old river port of Morpeth.
But flood silt up to seven metres deep has since been deposited over the vast floodplain.
The wooden vessel is, of course, much smaller though than the Tingira. St Michael was a 170-ton vessel once armed though with eight guns and surprisingly had a crew of 30. Originally registered in Bordeaux, France, she may have been built circa 1790 and was possibly originally seized by English sailors during the Napoleonic wars.
It has long been claimed Edward Close, the founder of Morpeth, bought his new wife to live onboard the ship as their first home in 1821, but this seems unlikely.
What is known is that St Michael was used in the South Sea island trade and in 1826 was used to transport convicts to Newcastle.
Two years later the vessel was converted into a supply depot ship for soldiers and convicts cutting cedar.
The ageing vessel then sank at her moorings opposite the township in 1841. She was supposed to be raised and reused but was still there in 1857.
Researchers have pinpointed a possible location at what is known as Taggarts Reef, a sandbar.
Late last year, a boat loaded with sonar equipment began to survey the Hunter River thereabouts. The effort was co-ordinated by marine archaeologist Dr Brad Duncan and Heather Berry from the Morpeth Heritage Conservation Group.
No news of a find has been announced to date, so, as they say, watch this space.