A twin 4.5-inch (113 mm) Mark 6 gun mount was fitted forward. A single Sea Cat surface-to-air missile launcher was fitted aft (on the Helicopter hangar roof), while two Oerlikon 20mm cannon provided close-in defence. A Limbo anti-submarine mortar was fitted aft to provide a short-range anti-submarine capability, while a hangar and helicopter deck allowed a single Westland Wasp helicopter to be operated, for longer range anti-submarine and anti-surface operations. "Ariadne" was fitted with a large Type 965 long range air search radar on the ship's mainmast, with a Type 993 short range air/surface target indicating radar and Type 978 navigation radar carried on the ship's foremast. An MRS3 fire control system was carried to direct the 4.5-inch guns. The ship had a sonar suite of Type 184 medium range search sonar, Type 162 bottom search and Type 170 attack sonar, together with a Type 199 variable depth sonar (VDS). She had a crew of 260 officers and other ranks.