Editing Knox-class frigate (section)

==Design==
Designated SCB No. 199C, the ''Knox'' was planned as the follow-on to the twin [[5-inch/38-caliber gun|5" gun]]-armed [[Garcia class frigate]]s and the [[RIM-24 Tartar|Tartar]] missile-equipped {{Sclass|Brooke|frigate|1}}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 [[RUR-5 ASROC]] [[Anti-submarine missile|anti submarine missiles]] together with the [[Gyrodyne QH-50 DASH|QH-50 DASH]] [[Unmanned aerial vehicle|drone]] [[helicopter]], while defensive armament was to be the [[MIM-46 Mauler|RIM-46 Sea Mauler]] short range [[Surface-to-air missile|anti-aircraft missile]] backed up by a single [[5"/54 caliber Mark 42 gun|5-inch/54 caliber Mark 42 gun]].<ref name="Fried p358-0">Friedman 1982, pp. 358–360.</ref>

[[File:Knox-class frigate drawing 1974.png|thumb|left|Drawing of a ''Knox''-class frigate as built.]]

The design soon ran into problems however, with the US Navy deciding to switch to conventional {{cvt|1200|psi}} boilers, requiring a redesign, and the ships became longer and heavier in order to accommodate the less compact power plants. Furthermore, Sea Mauler was cancelled in 1965, leaving the ships to complete without any anti-aircraft system except the 5" gun.<ref name="Fried p360">Friedman 1982, p. 360.</ref><ref name="conways47 p598-9" />

[[File:USS Fanning (FF-1076) overhead view.jpg|thumb|left|Overhead view of ''Knox''-class frigate {{USS|Fanning|FF-1076}}]]

The steam plant for these ships consists of two [[Combustion Engineering]] or [[Babcock & Wilcox]] [[Water-tube boiler#D-type Boiler|"D" type boilers]], each equipped with a high-pressure (supercharger) forced draught air supply system, with a plant working pressure of {{cvt|1200|psi}} and {{cvt|1000|°F}} superheat and rated at {{cvt|35000|shp}} driving a single [[propeller|screw]]. This gives them a speed of {{cvt|27|kn}}.<ref name="S&A12 p121"/><ref name="Combat Fleets 90 p807">Prézelin and Baker 1990, p.807.</ref>

The ships were designed primarily as [[anti-submarine warfare]] (ASW) platforms.<ref name="conways47 p598-9" /> Their main anti-submarine sensor was the large bow-mounted [[AN/SQS-26]]CX low-frequency scanning [[sonar]], operating as an active sonar at a frequency of about 3.5&nbsp;kHz and passively at 1.5–4&nbsp;kHz. The active modes of operation included direct path, to a range of about {{cvt|20000|yd}}, bottom bounce, and convergence zone, which could give ranges of up to about {{cvt|70000|yd}}, well outside the capability of ASROC, and requiring the use of a helicopter to exploit.<ref name="conways47 p598-9" /><ref name="WNS97 p629-0">Friedman 1997, pp. 629–630.</ref><ref name="conways47 p553">Gardiner and Chesneau 1995, p. 553.</ref> An eight-round ASROC launcher (with 16 missiles carried) was fitted between the gun turret and the bridge, backed up by four fixed {{cvt|12.75|in}} [[Mark 32 Surface Vessel Torpedo Tubes|Mark 32]] anti-submarine torpedo tubes. A flight deck and hangar for operating the DASH drone helicopter was fitted aft.<ref name="jfs71 p481"/><ref name="conways47 p598-9"/>