Believing a distress call was being sent out, the coastguard eventually found it was a false alarm when the they discovered it was coming from a GPS unit in a car on a ferry. The coastguard had spent three hours attempting to find the source of the distress call before concluding it was actually coming from a nearby ferry, the European Endeavour, crossing the Irish Sea. It was the first such incident, but not necessarily the last with more vehicles being fitted with devices which can send out these signals. The cause? It’s thought the rocking motion of the ferry set it off.