First seen by a local diver in 1971 and designated under the Protection of Wrecks Act 1973, the Schiedam wreck had long been buried under shifting sands until it was rediscovered by local divers David Gibbins, an archaeologist and novelist, and Mark Milburn of Atlantic Scuba in Penryn.

“We’d searched the cove many times for the Schiedam, but only seen sand," the divers have reported in a statement. “Then the breakthrough came one day after a storm.

“Snorkelling north over the cove, we saw not just one cannon, but three. It was incredibly exciting. One of the guns was among the longest we’d ever seen on a wreck, standing proud of the seabed on a rocky ledge with the muzzle poking out, almost as if it were on a gun-carriage.

“Exploring the reefs around the guns, we saw other amazing artefacts – concreted musket barrels, cannonballs, lead musket and pistol shot, and even an iron hand-grenade, the wooden plug for the fuse still intact.

“We knew that most of what we were seeing was cargo carried from the English colony at Tangier, making the wreck a fascinating window into a forgotten corner of history.”

The Schiedam was lost in April 1684 while part of a fleet carrying ordnance, tools, horses and people back to England from Tangier in what is now Morocco, as the English evacuated the port following years of siege by the Moors.

Originally a Dutch merchantman, the Schiedam had been captured by Barbary pirates off Spain the previous year and her crew enslaved. Soon afterwards she was captured again, this time by a Royal Navy ship commanded by the young Cloudesley Shovell (later noted as the admiral lost with his fleet in 1707 in the Scilly Isles).

Shovell brought the Schiedam to Tangier, where diarist Samuel Pepys, then an Admiralty official sent to help oversee the evacuation, wrote about the ship.

The big gun seen by the divers was a demi-culverin, one of a number recorded among the ordnance at Tangier but the only one from the colony known to survive.

The hand-grenade is one of the earliest-known examples to be found archaeologically.

“Hand-granadoes” had been used by English regiments only for a few years but were among the first arms requested for Tangier in 1662 for use in the defence against the Moors.

When the Moors captured an outlying fort in 1680 they seized a large store of hand-grenades and other armaments, swinging the siege in their favour and influencing the the English decision to abandon the colony a few years later.

Although the Schiedam dates back a century before the setting of Poldark “you would have seen local people lining the shore just as the film crew were that day in 2014, and flotsam coming ashore at exactly the same place,” said Gibbins.

A letter written soon after the wrecking to Lord Dartmouth, Admiral of the Fleet, suggests that the locals salvaged what they could but were far from the murderous Cornish wreckers of legend: “All the guns and mortar pieces may be saved, but palisades, muskets, rigging etc are mostly embezzled, though the justices and gentlemen of the country are extremely civil and save what they could; and the country very kind to the poor people.”

Historic England (HE) is responsible for managing the wreck-site. “We are delighted to work with divers like Mark and David to help ensure that England’s protected wreck sites are enjoyed and protected for years to come,” said HE Maritime Archaeologist Alison James.

“They are helping to ensure that the story of the site is not lost and is known to a wider audience.”

Further exploration of the Schiedam is planned for next year. 

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