Knox-class frigate

The Knox class was a group of 46 frigates of the United States Navy, the largest, last and most numerous of its second-generation anti-submarine warfare escorts. They were laid down as ocean escorts, formerly called destroyer escorts, and were redesignated as frigates on 30 June 1975, their hull designation changing from DE to FF. The lead ship, Knox, was commissioned on 12 April 1969. A single screw was driven by a steam plant of two 1,200 psi boilers rated at 35,000 shaft horsepower, giving about 27 knots, and the class was the Navy's last destroyer-type design with a steam turbine powerplant. Armament centred on an eight-round ASROC launcher, Mark 32 torpedo tubes, a 5-inch Mark 42 gun and the large bow-mounted AN/SQS-26 sonar. Nicknamed McNamara's Folly, the ships were all retired from US service by 1994, though some served on with Egypt, Taiwan, Thailand and Mexico.