England’s most valuable shipwrecks to be protected with ‘forensic marking’

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England’s most valuable shipwrecks are to be protected from criminal divers by new “forensic marking” technology that enables bronze cannons and other precious items to be traced and identified when offered for public sale. 

Of the 37,000 wrecks lying off the coast of England, 57 of the most important sites are to be “marked” underwater using the technique, which has taken seven years to refine to ensure it can withstand the rigours of the marine environment. 

Mark Harrison, head of heritage crime strategy at Historic England, the public body that looks after sites of historic interest, said on Wednesday that the technology would act as a “clear deterrent” to those looking to plunder protected sites.

Specialist divers have started work on the Klein Hollandia, a 17th-century Dutch warship that was sunk off the Sussex coast in 1672, applying the invisible markings to its cannons. 

Wrecks dating from before 1700 are extremely rare and little documentation exists on the design and construction of Dutch ships of the period. 

Boarded by English sailors in an attack on a Dutch convoy before going down, the wreck was identified in 2019 and remains in a “remarkable” condition.

The heritage body has joined forces with its Dutch counterpart, the Cultural Heritage Agency of the Netherlands, to develop the forensic marking system and research the site.

Hefin Meara, maritime archaeologist at Historic England, said: “This is a game-changer for us. It gives us peace of mind to know that these at-risk objects have a marker on them and it’s going to be a big deterrent to anybody thinking that they can take this stuff and get away with it.”

Underwater heritage crime has long been a problem in Britain. In 2014, two men were convicted of plundering objects such as cannons and propellers from wrecks off the Kent coast.

Another man was fined and given a custodial sentence in 2015 for attempting to sell three bronze cannons that turned out to have been from Charles II’s flagship, which sunk off Southend in 1665. Another was found guilty in 2016 of unlawfully raising tin ingots from a 19th-century wreck off the Cornish coast. 

Meara said the initiative would also help put off the souvenir hunters who, after visiting modern but nonetheless protected wrecks, might take home engine parts or fittings from the bridge as a keepsake. 

The idea of forensic marking for marine heritage was prompted by the technique being applied to the lead roofs of churches in England, where high prices for metals have led to a spate of thefts.

Meara added that bronze cannons from shipwrecks typically went to two markets: private collectors or metal dealers. 

A network of volunteer divers and boat owners already helps to safeguard wreck sites, but Historic England said many were too far off the coast to be continually monitored. 

“If someone breaks the law and removes any property, the new markings will give police the ability to link the offender to the crime scene and implement criminal proceedings,” said Harrison.