Of the 156 U-boats that surrendered to the allies at the end of the war, 116 were scuttled as part of Operation Deadlight.[1] The Royal Navy carried out the operation, and planned to tow the submarines to three areas about 100 miles (160 km) north-west of Ireland and sink them.[2] The areas were codenamed XX, YY and ZZ.[2] They intended to use XX as the main scuttling area, while towing 36 boats to ZZ to use as practice targets for aerial attack.