 It was originally intended to fit a twin 40 mm L/70 Bofors anti-aircraft mount aft, but in 1957 it was decided to fit the Seacat anti-aircraft missile instead.Seacat was not yet ready, and "Rhyl" was completed with a single L/60 Bofors 40 mm mount aft as a temporary anti-aircraft armament.The design anti-submarine armament consisted of twelve 21-inch torpedo-tubes (eight fixed and two twin rotating mounts) for Mark 20E Bidder homing anti-submarine torpedoes, backed up by two Limbo anti-submarine mortars fitted aft.