A robot submarine operated by researchers from the University of Limerick, and guided by a navigation system designed at the university, has shed new light on several first World War era shipwrecks off the Irish coast.
The operation by the ROV (remote operated vehicle) Étáin was the first dive on several wrecks about which very little was known, including the only German U-Boat sunk by US forces in the first World War.
It was operated by engineers from the Centre for Robotics and Intelligent Systems (CRIS) at UL and Marine and Renewable Energy Ireland (MaREI), and operated from the research vessel Celtic Explorer.
The mission was enabled by artificial intelligence technologies that allowed the submarine to skirt some of the more dangerous items strewn around the seabed which would normally be difficult for a human operator to detect, such as discarded fishing gear.
In doing so, the ROV was able to capture photographs and sonar data of the wrecks, about which only sparing details were known before.
Pots and pans
"Close quarter inspection of these sites with an ROV is technically challenging and hazardous due to the presence of abandoned fishing gear. The blended control and automation of the ROV provided by our UL developed OceanRINGS software and other UL systems allows us to safely complete these missions," said Dr Gerard Dooley, chief scientist for the survey.
“Near the wreck we saw pots and pans and unexploded ordnance scattered on the seafloor reminding us of the human misfortune that occurred at the time of the sinking.”
“Every wreck has its own story, so it’s always interesting to locate long forgotten shipwrecks and then try to determine the identity of the wreck and understand something of the circumstances of the tragedy,” he said
The U-Boat which was surveyed, U-58, was sunk on November 17th, 1917 by the US destroyer Fanning after an encounter off Cobh, although almost all the German crew survived the battle and were interned in the US for the remainder of the war.
A camera survey undertaken on one of the wrecks showed that it had been colonised by an array of anemones, solitary corals, oysters and brachiopods.
Using a process called multibeam mapping on one wreck, which is thought to be that of the Ocean Liner SS Canadian, the surveyors were able to detect a large debris field that was not visible on the original map of the wreck, suggesting a violent impact with the seabed.