 "Tyr" was built at Voldnes Skipsverft in 1981 and was used as an offshore standby-ship in the North Sea under the name MS "Standby Master", yard number 31.The Royal Norwegian Navy took her over in December 1993, and "Tyr" went through a comprehensive rebuilding and modernization program between 1994 and February, 1995 at the Mjellem & Karlsen shipyard in Bergen.Under the rebuilding "Tyr" was equipped with new thrusters, the bridge was expanded and a mine hangar was built on the aft-deck, and new hydraulic equipment was installed on the work-deck.