High Quality Content by WIKIPEDIA articles! HMS Tracker (P274) is an Archer-class (P2000) patrol and training vessel of the British Royal Navy, used for training purposes by the Oxford University Royal Naval Unit (URNU). Part of the 1st Patrol Boat Squadron (1PBS), the vessel is based at HMNB Portsmouth, and is the third ship to bear the name HMS Tracker. Tracker`s primary role is to be the training ship for Oxford University Royal Naval Unit (Oxford URNU), but she also trains regular officers in navigation, supports fleet training, usually by acting as the enemy, provides sea experience to the Cadet Forces and can provide VIP transport.