Niteroi

The Brazilian navy ordered six frigates from the British Vosper-Thorneycroft shipyards in 1970. Based on the company's Mk 10 frigate design, four are specialist antisubmarine warfare frigates and two are more general purpose.

The ASW frigates have Branik anti-submarine missiles, a development of the Australian Ikara system- whereas Constituicao and Liberal have a second 4.5-inch DP gun turret instead and a rack of depth charges. Most importantly, the latter vessels also have four Exocet missiles, although the Brazilian navy announced in 1991 that the ASW frigates would be receiving Exocet too.

Plans to replace the Sea Cat SAMs in favor of Phalanx CIWS have also been mooted; sensors and countermeasures are being upgraded.