22 nautical miles off the coast of Yorkshire, England , archeologists found the UC-47, one of the first German U-boat sunken by English forces during World War I in November 1917, along with torpedoes of which it is not known whether they are still active.
The discovery of the 30-meters long and 5-meters wide U-boat took place last April, when a team led by Mexican archeologist Rodrigo Pacheco Ruiz, a researcher of the University of Southampton, was performing an inspection of underwater infrastructure. In April, near the site, oil company staff – considered essential workers during the pandemic, was performing works that led to the vessel.
The submarine, as explained by Pacheco Ruiz, was “marked” in the nautical letters as the UC-47, that is, there is only a name without a description so, with the help of robots, they made a 3D mapping of the site on April 25.
The mapping meant facing the first obstacle because the submarine is located at the North Sea, which is known for being turbulent, so they noticed they could not conduct works of photogrammetry, which is the reconstruction of places from photographs.
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Instead of photogrammetry, the experts used technology based on acoustic pulses that was developed during WWI .
“When a sound bounces in an object, it causes an echo and it also bounces. The time the acoustic pulse takes to bounce and come back to the receiver is measured. This system works with thousands of acoustic sounds that create a tridimensional model. Each point of the 3D model is an acoustic reflection and we constantly register billions of points. That is, we use the sound to know the shape of the seafloor and the archeological site,” he explains.
The works were done through robots operated from a 100-meters long boat that was on the surface and a crew comprised of 40 members. “These vessels are quite expensive; renting a boat costs approximately £80,000 per day. It is cutting-edge technology that is used to have a map of the seafloor with submillimetric accuracy.”
The Remotely Operated Vehicles (ROV), according to the Mexican researcher, have a kind of “umbilical cord” that allows them to go as far as 4km deep, although this case only required 56 meters.
Through their cameras, the robots were able to capture different aspects of the metal vessel that has been sunken for almost 103 years; likewise, they also registered elements about its conservation status.
“We must consider the submarine has been at the bottom of the sea for over 100 years because it was sunk in 1917. Metal is an element that suffers great erosion underwater. Last year, we found a 500-years-old ship that survived because it was made of wood, a material that is well-conserved in underwater environments. Metal corrodes and there is solidification.”
Despite the turbulent sea, the cameras showed the submarine’s hull, propellers, and engines are complete and it could be seen that the tower was damaged by a Royal Navy vessel.
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Historical vessel
Mexican archeologist
Rodrigo Pacheco explains that the UC-47 was used by the German to build a mine barrier, which was used to sink the Allies ships.
“The vessel has circular holes, which are where the mines were kept; those hatches are intact. The submarine has survived because it is 22 nautical miles off the coast where diving is not as easy as in other places. During WWI , these submarines were part of the German vanguard to prevent the Allied nations from receiving essential provisions. Moreover, they were the first submarines and the English did not know how to react because there was no such naval intelligence.”
Over time, Great Britain learned how to trace and sink submarines. Rodrigo Pacheco Ruiz mentions that in 1918, there was a group of divers known as the “Tin-Openers” who submerged to recover key information about mines.
“Apart from mines, these submarines had official documents from Germany that described the position of the mines and that represented essential information for Great Britain ,” he says.
By knowing the information retrieved by the “Tin-openers,” Pacheco Ruiz and his team posed two hypotheses: that the submarine could have been one of the firsts to be inspected by the team of divers or that it had never been inspected.
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“We have searched for information for the SARS-CoV-2 virus has prevented us from directly visiting the archives; we have only been able to investigate the online archives. It could be that this submarine has never been penetrated by divers, which suggests the submarine could be intact inside and that there could be eventual archeological research,” he mentioned.
In order to prove or dismiss their ideas, Rodrigo Pacheco Ruiz is already working on the project for a second research on the site; nevertheless, he said they would use non-intrusive techniques.
We are interested in developing technology that scans the vessel’s inside without touching anything because once the site is excavated, it begins to get lost.”
The development of new technology will be funded by companies and universities such as the Coastal and Offshore Archaeological Research Services and the University of Southampton, and it will also be possible thanks to alliances with other institutions, including the Institute of Archeological Research of the National Autonomous University of Mexico.
As stressed by the Mexican expert, research on the submarine is highly relevant because the site still has live ordnance, that is, there are torpedoes that could be active.
“The site is a war cemetery; all the crew died in the British attack and the bodies were never rescued. If the “Tin-Openers” did not come in, we might still find human remains. The submarine is one of the firsts ones and it can provide more information. We’re interested in a better understanding of history.
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A latent risk
Rodrigo Pacheco Ruiz asserts that archeological sites from the two world wars are constantly targeted by looters because there are myths about the vessels carrying treasures.
“There has always been a looting risk; there are three ships from the same time that are closer to the coast of Yorkshire that have already been looted and devoured by treasure hunters. They are people with little archeological knowledge that do not understand the conservation process.”
The researcher mentions that the problem worsens because the United Kingdom’s legal protection is not applied further than 12 miles.
“The UC-47 is not protected; it is in international waters and law does not protect it,” he stresses.
Last year, Pacheco Ruiz found the remains of a 500-year-old ship at the Baltic Sea. In this regard, he says there is a plan in the making for a second season that allows conducting sampling, but that there has not been much progress due to the pandemic.
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