Permit-class submarine: Difference between revisions

*[[New York Shipbuilding]]

*[[General Dynamics Electric Boat]]

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The ''Thresher'' class was one of several results from a study commissioned in 1956 by [[Chief of Naval Operations]] (CNO) Admiral [[Arleigh Burke]]. In "[[Project Nobska]]", the Committee on Undersea Warfare of the [[United States National Academy of Sciences]], collaborating with numerous other agencies, considered the lessons of [[submarine warfare]] and [[anti-submarine warfare]] learned from various prototypes and experimental platforms. The design was managed under project [[Ship Characteristics Board|SCB 188]].<ref>Friedman, p. 143</ref>

 

==Design==

 

The small sail of ''Thresher'' (the smallest fitted to an American SSN) compensated for the increased drag of the longer hull, giving ''Thresher'' a top speed of {{convert|33|kn|lk=in}}, the same as the ''Skipjack''s, according to one recollection.<ref>Polmar, Norman; Moore, K. J. (2004) ''Cold War Submarines: The Design and Construction of U.S. and Soviet Submarines'', Potomac Books, p. 363</ref> However, the small sail had disadvantages as well, including room for only one [[periscope]] and a reduced number of electronics masts, less convenient surfaced operation in rough seas, and an increased possibility of "broaching" (inadvertent surfacing) at [[periscope depth]] in rough seas.<ref name="Friedman, pp. 143-146">Friedman, pp. 143–46</ref>

Only ''Thresher'' was fitted with a five-bladed symmetric [[Propeller|screw]], very similar to the ones originally fitted to the ''Skipjack''s, which allowed her to reach this speed. During [[Sea trials|trials]] of the ''Skipjack'' class, it was found that the propeller produced noise below [[cavitation]] depth. It was determined that the source of this noise, called blade-rate, was the blades of the screw vibrating when they hit the wake of the sail and control surfaces.<ref name="FriedmanSubs1"/> This produced a noise that could carry for many miles and could be used by an enemy submarine to set up a firing solution because the frequency of blade-rate was directly related to the speed of the submarine (the RPM of the screw). The solution was to either make the screw smaller so it did not hit the wakes of the sail and control surfaces, which would cavitate more easily because of its increased speed, or have a large screw that gently interacted with these areas of disturbed water. The latter solution was chosen for all subsequent American SSNs. ''Permit'' and later submarines of this class had seven-bladed skewback screws, which reduced the problem of blade-rate, but reduced the submarines' top speed to {{convert|29|-|28|kn}}. ''Jack'' was designed with counter-rotating screws, each of which were smaller than the standard seven-bladed screw, as an alternative solution to the blade-rate problem.<ref name="FriedmanSubs1"/>

 

 

==Armament==

 

The maximum weapons load was 23 torpedoes/missiles or, theoretically, up to 42 Mk 57, Mk 60, or Mk 67 [[Naval mine|mines]]. Any mix of mines, torpedoes, and missiles could be included.<ref>''War Machines Encyclopedia'', Aerospace Publishing Ltd., Italian version printed by De Agostini, pp. 526–27</ref>

 

==Construction==

 

 

The engine room of {{USS|Jack|SSN-605|2}} was lengthened by {{convert|10|ft|m}} to accommodate an experimental [[direct drive|direct-drive]] propulsion system using concentric counter-rotating propellers. Although counter-rotating propellers produced impressive gains in speed on the experimental {{USS|Albacore|AGSS-569|2}}, in ''Jack'' the results were disappointing because of the difficulty in sealing the shaft. ''Jack'' was also used to test polymer ejection that could reduce flow noises that degraded sonar performance.{{citation_needed|date=August 2019}}

 

 

{| class="wikitable" style="font-size:97%;"

!Launched

!Commissioned

! width="35%" | Fate

|-

|9 July 1960

|3 August 1961

|-

|{{USS|Permit|SSN-594|2}}

|SSN-594

|16 July 1959

|29 May 1962

|-

|{{USS|Plunger|SSN-595|2}}

|SSN-595

|2 March 1960

|9 December 1961

|21 November 1962

|-

|{{USS|Barb|SSN-596|2}}

|11 Feb 1962

|24 August 1963

|-

|{{USS|Pollack|SSN-603|2}}

|SSN-603

|14 March 1960

|17 March 1962

|26 May 1964

|-

|{{USS|Haddo|SSN-604|2}}

|SSN-604

|9 September 1960

|18 August 1962

|16 December 1964

|-

|{{USS|Jack|SSN-605|2}}

|SSN-605

|16 September 1960

|24 April 1963

|31 March 1967

|-

|{{USS|Tinosa|SSN-606|2}}

|SSN-606

|24 November 1959

|9 December 1961

|17 October 1964

|-

|{{USS|Dace|SSN-607|2}}

|18 August 1962

|4 April 1964

|-

|{{USS|Guardfish|SSN-612|2}}

|15 May 1965

|20 December 1966

|-

|{{USS|Flasher|SSN-613|2}}

|SSN-613

|14 April 1961

|22 June 1963

|22 July 1966

|-

|{{USS|Greenling|SSN-614|2}}

|SSN-614

|15 August 1961

|4 April 1964

|3 November 1967

|-

|{{USS|Gato|SSN-615|2}}

|SSN-615

|15 December 1961

|14 May 1964

|25 January 1968

|-

|{{USS|Haddock|SSN-621|2}}

|21 May 1966

|22 December 1967

|-

|}

{{reflist|30em}}

* Gardiner, Robert and Chumbley, Stephen, ''Conway's All the World's Fighting Ships 1947–1995'', London: Conway Maritime Press, 1995. {{ISBN|1-55750-132-7}}.

* Hutchinson, Robert, ''Jane's Submarines, War Beneath The Waves, From 1776 To The Present Day'', Harper Paperbacks, 2005. {{ISBN|0-06081-900-6}}.

* Polmar, Norman (2004). ''Cold War Submarines: The Design and Construction of U.S. and Soviet Submarines, 1945-2001''. Dulles: Brassey's. {{ISBN|978-1-57488-594-1}}.

 

{{Permit class submarine}}

 

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