On 13 May 2003, while on exercise in the Arctic and travelling at a depth of 60 metres, "Tireless" collided with an iceberg. There was no prior warning of the impending collision from passive sonar or other onboard sensors. The submarine's bow was forced down nine degrees and the vessel subsequently broke free of the iceberg at a depth of 78 metres. Some damage was sustained to the upper section of the boat. Before the incident, the Royal Navy had not conducted under-ice operations since 1996.