Editing Knox-class frigate (section)

==Modifications==
The {{USS|Joseph Hewes|FF-1078}} and subsequent ships of the class were modified to enable them to serve as flagships. The primary change was a slightly different arrangement of the "Officer's Country" staterooms with additional staterooms in a new 01 level structure which replaced the open deck between the boats. The stateroom on the port side under the bridge was designated as a "flag" stateroom, with additional staterooms for flag staff when serving as a flagship. These ships have been referred to as the ''Joseph Hewes''-sub-class {{citation needed|date=September 2018}}.

[[File:USS Bowen (FF-1079).jpg|thumb|left|Bow modifications including bulwark and horizontal spray strake on {{USS|Bowen|FF-1079}} in 1984.]]

The ''Knox'' class had been criticized for deck wetness and there were a number of instances of damage to the forward weapons mounts in heavy seas, so the class were refitted with "hurricane bows" beginning with {{USS|Bagley|FF-1069|3}} in 1979. The modification heightened the bow section, adding bulwarks and spray [[strake]]s to prevent burrowing into on-coming seas and to better protect the forecastle armament.<ref>{{cite book |url= https://books.google.com/books?id=Tzp58htKLkEC&pg=PA360 |last= Friedman |first= Norman |title= US Destroyers: An Illustrated Design History |publisher= Naval Institute Press |location= Annapolis |year= 2004 |page= 360 |isbn= 978-1-55750-442-5 |edition= Revised }}</ref>

[[File:USS McCandless (FF-1084).jpg|thumb|left|Aerial view of ''Knox''-class frigate {{USS|McCandless|FF-1084}}]]

Twenty-five ships of the class (DE-1052, 1056, 1063–1071 and 1078–1097) were refitted with the AN/SQS-35(V) Independent Variable Depth Sonar, an active sonar operating at about 13&nbsp;kHz.<ref name="conways47 p598-9" /><ref name="S&A12 p121">Polmar 1981, p. 121.</ref><ref name="Combat Fleets 90 p807"/> The IVDS' sonar transducers were packaged within a 2-ton fiberglass-enclosed "fish" containing the sonar array and a gyro-compass/sensor package launched by the massive 13V Hoist from a stern compartment, located just beneath the main deck, to depths of up to {{cvt|600|ft|m|-1}}. The IVDS could take advantage of water layer temperature conditions in close-range (less than {{cvt|20000|yd|round=5}}) submarine detection, tracking and fire-control.{{citation needed|date=May 2015}} The AN/SQS-35 "fish" was later modified to tow an AN/SQR-18A TACTASS passive towed array sonar.<ref name="Combat Fleets 90 p808">Prézelin and Baker 1990, p.808.</ref><ref name="jfs85 p718">Moore 1985, p. 718.</ref> The DASH drone proved unreliable, and following its withdrawal in 1973, the ships' helicopter facilities were expanded to accommodate the larger, manned, [[Kaman SH-2 Seasprite|Kaman Seasprite]] [[Light Airborne Multi-Purpose System|LAMPS 1]] helicopter.<ref name="jfs85 p717">Moore 1985, p. 717.</ref>

Thirty-one ships (DE-1052–1069 and 1071–1083) were fitted with an eight-round Basic Point Defence Missile System (BPDMS) launcher for [[RIM-7 Sea Sparrow]] missiles in place of the cancelled [[MIM-46 Mauler|Sea Mauler]] short range surface to air missile system, while {{USS|Downes|FF-1070|3}} was fitted with a NATO Sea Sparrow (IBPDMS) launcher. It was planned to equip the other 14 ships with [[MIM-72 Chaparral|Sea Chaparral]], based on the [[AIM-9 Sidewinder|Sidewinder]] air-to-air missile, but this plan was abandoned.<ref name="Fried p361">Friedman 1982, p. 361.</ref> Most ships were refitted with a {{cvt|20|mm}} [[Phalanx CIWS]] aft during the 1980s, replacing the Sea Sparrow launcher.<ref name="Combat Fleets 90 p808"/>

In the 1970s, several ships received an interim [[surface warfare]] upgrade allowing [[AGM-78 Standard ARM|Standard ARM]] anti-radar missiles to be fired from the ships' ASROC launcher.<ref name="Fried p361"/> Later, all ships were modified to launch [[Harpoon (missile)|Harpoon]] anti-ship missiles from the ASROC launcher, which could carry two Harpoons, with two more carried in the ships' ASROC magazine.<ref name="Combat Fleets 90 p808"/>