 It was rejected for RN use because of doubt about its sustained firing, the large stocks of surplus WW2, single 4.5- and twin 4-inch guns which the RN claimed wrongly were close to the new 4-inch N(R) in performance, and mainly because it was a private out-of-house, Vickers design  The ships were modernised in Britain in 1975, and decommissioned in the late 1990s.Chile decided to upgrade its destroyer fleet in the early 1950s and turned to British yards to fulfill the order.Bids were received from Vickers and Thornycroft (Freedman 2006); the Vickers design was chosen.