HMNZS Otago (F111) was a Rothesay-class (Type 12M) frigate acquired from the United Kingdom by the Royal New Zealand Navy (RNZN) before completion. Otago and were the only two Otago-class frigates; they differ from the Rothesays that served in the Royal Navy as they were not reconstructed to the Type 12I Leander-class standard with hangar and landing pad for a Westland Wasp anti-submarine helicopter as the main weapon system with torpedoes, depth charges and SS.12/AS.12 missiles to engage fast attack craft and surfaced submarines. Otago was launched on 11 December 1958 by Princess Margaret, and was commissioned into the Royal New Zealand Navy on 22 June 1960. The ship was named after the province of Otago in New Zealand's South Island, and associated with the city of Dunedin. The sensors of the Otago were generally updated in line with those of the Royal Navy's Rothesays to year 1980 standard but Otago unlike the RN frigates, was not fitted as a specialised anti-submarine frigates and retained the medium range air- and surface-warning Type 277Q radar, and original Type 275 and Type 262 fire control. Otago had Seacat anti-aircraft missiles fitted in New Zealand in 1963-64. Design The Rothesay-class was an improved version of the anti-submarine frigate, with nine Rothesays ordered in the 1954–55 shipbuilding programme for the British Royal Navy to supplement the six Whitbys. In February 1956, New Zealand purchased the Rothesay-class frigate Hastings, which was on order for the Royal Navy, to be renamed Otago and an additional Rothesay, to be called . The New Zealand ships were largely the same as those built for Britain, but had revised internal arrangements, with air conditioning, bunks for the crew rather than hammocks, and cafeteria dining. Otago was long overall and between perpendiculars, with a beam of and a draught of . Displacement was standard and full load. The Rothesays were powered by the same Y-100 machinery used by the Whitby class. Two Babcock & Wilcox water-tube boilers fed steam at and to two sets of geared steam turbines which drove two propeller shafts, fitted with large ( diameter) slow-turning propellers. The machinery was rated at , giving a speed of . The ship had a crew of 219 officers and other ranks. A twin 4.5-inch (113 mm) Mark 6 gun mount was fitted forward, with 350 rounds of ammunition carried, with a single Mk 9 L60 40 mm Bofors guns