Designated SCB No. 199C, the "Knox" was planned as the follow-on to the twin 5" gun-armed Garcia class frigates and the Tartar missile-equipped s. Their initial design incorporated the prior classes' pressure-fired boilers in a similar-sized hull designed around the massive bow-mounted AN/SQS-26 sonar, with increased endurance and reduced crew size. Anti-submarine armament was to consist of ASROC anti submarine missiles together with the QH-50 DASH drone helicopter, while defensive armament was to be the RIM-46 Sea Mauler short range anti-aircraft missile backed up by a single 5-inch/54 caliber Mark 42 gun.