'The Trafalgar-class submarine HMS Turbulent has completed a weapons upgrade that will extend its service life in the UK Royal Navy (RN) by two years. The 5,200-ton boat received upgrades to its communications, IT, sonar, command and weapon discharge systems during the 15-month refit in Plymouth, enabling it to fire the Tomahawk torpedo-tube-launch (TTL) Block IV land-attack cruise missile.