View source for Passive Underwater Fire Control Feasibility System

{{Short description|Passive sonar system for submarines}}
[[File:USS Harder (SS-568).jpg|thumb|{{USS|Harder|SS-568}} with the three distinctive shark-fin PUFFS domes]]
[[File:Onslow fin and Micropuffs.JPG|thumb|Fin and central section of {{HMAS|Onslow}}. The three orange covers on the casing are protective sheathes over the submarine's Micropuffs sonar]]
'''Passive Underwater Fire Control Feasibility System''' (or Study) ('''PUFFS''') is a [[passive sonar]] system for [[submarine]]s. It was designated AN/BQG-4 and was primarily installed on [[United States Navy]] conventional submarines built in the 1950s beginning with the {{Sclass|Tang|submarine|4}}, and also those converted to [[GUPPY]] III or otherwise modernized in the 1960s. It was also equipped on the nuclear-powered {{USS|Tullibee|SSN-597}}. It was also installed on the {{USS|Thomas A. Edison|SSBN-610}} but never achieved operational status. Its transducers can be seen on pictures of the vessel. A version known as "Micropuffs" was fitted on {{Sclass|Oberon|submarine|2}}s for the [[Royal Australian Navy]], and as Type 2041 on the [[Upholder/Victoria-class submarine|''Upholder''-class]] for the British [[Royal Navy]]. This class still serves in the [[Royal Canadian Navy]] as the ''Victoria'' class, where Micropuffs is known as BQG-501.<ref>Friedman, p. 246</ref> The system was notable for three tall, fin-like domes topside, except on Micropuffs installations (''Tullibee'' had the second dome built into the aft end of the sail). The system was retained on several submarines transferred by the US to foreign navies. It was associated with long-range passive detection of targets for the [[Mark 45 torpedo|Mark 45 nuclear torpedo]] and other weapons. Most submarines backfitted with it were also lengthened {{convert|12|-|16|ft}} to accommodate additional electronics and plotting rooms. It was also planned for {{Sclass|Thresher|submarine|5}} and {{Sclass|Sturgeon|submarine|4}} [[nuclear submarine]]s, but was not fitted on them except Micropuffs experimentally on {{USS|Barb|SSN-596|2}} and {{USS|Haddock|SSN-621|2}}.<ref>{{cite book| last = Friedman| first = Norman| title = U.S. Submarines Through 1945: An Illustrated Design History| publisher = [[United States Naval Institute]]| year = 1995| location = [[Annapolis, Maryland]]| pages = 16–17, 43| isbn = 1-55750-263-3 }}</ref> With the exception of the four Canadian ''Victoria''-class submarines, all PUFFS-equipped submarines have been disposed of or preserved as museum ships.
== See also ==
* [[Greater Underwater Propulsion Power Program]] (GUPPY)
== References ==
{{reflist}}
* {{Cite book
|last=Alden  |first=John D., Commander (USN Ret)
|title=The Fleet Submarine in the U.S. Navy: A Design and Construction History
|year=1979
|publisher=Arms and Armour Press  |location=London
|isbn=0-85368-203-8
}}
*''Sub vs Sub'', Cdr R Compton Hall, [[Orion Books]], 1989
[[Category:Military sonar equipment of the United States]]
[[Category:Submarine warfare]]
[[Category:Anti-submarine warfare]]