Some upgrades for older vessels
HMS Arrow, 1979
The two Orange Nell armed Type 80 frigates were retired from their primary duties quite early on due to the limitations of the SAM system. HMS Arrow became the trials ship for the Confessor SAM system, to enter service as the Sea Wolf and the successor to Orange Nell. A 12-cell VLS was fitted forward and all other armament removed. A prototype Type 996 radar was also fitted, along with a dedicated IFF antenna. She served on missile development from 1976 to 1992 when she was finally decommissioned. Other weapons tested aboard included Shorts Seastreak and development work on the Type 911 and Type 912 trackers.
HMS Slingshot, 1977
The other Type 80 frigate with the Orange Nell system was converted to a patrol frigate at the height of the 'Cod Wars'. The missile system and Limbo was replaced by a 375mm Bofors A/S mortar mounted forward. Her already upgraded SeaCat 2 systems (installed in the late 1960s) were retained and another MRS-3 fitted forward. Two triple lightweight torpedo tube mounts were also fitted and the old 40mm Bofors (removed in 1968) were replaced by 20mm cannon. HMS Slingshot served in this guise from 1976 to 1983.
HMS Crescent, 1993
HMS Comet, 1988
Following the Falklands War the Type 21 frigates received a single Phalanx CIWS aft and newer 20mm GAM-BOI mounts. By the early 1990s most had also received the Type 996 radar and GWS-60 Harpoon missiles instead of the heavier Woomba SSMs. During the early 1990s four of the class also received a Seastreak CIWS missile system aft, replacing the Phalanx.