In this second segment, we will continue our discussion on Cold War Submarines by exploring NARA records that can be utilized to research the developmental shift from diesel-electric boats to nuclear fast-attack submarines with the modern,  more hydrodynamic, "tear-drop" shape. We will also address what series relate to  operational records for this period, and alternative repositories where further research can be done outside of the National Archives. (Part III of this series, to be published next quarter, will discuss records about the development and available operational and command records to the Fleet Ballistic Missile (FBM) submarines.)


To understand how modern submarines evolved from World War II boats, one needs to revisit the end of World War II and the German and Japanese innovations to their Type XXI and I-200 submarines. For all technical purposes, the submarines of World War I, World War II, and the GUPPYs of the early Cold War were submersibles, but not true submarines. Running on diesel engines, the earlier boats were faster and could maintain a higher speed longer on the surface as compared to their differentially slower speed when using battery power while submerged. They were also heavily dependent on surfacing to renew the air supply in the boat and to recharge the batteries. The post-war innovations from Germany and Japan improved these situations, but did not solve the slow and cumbersome speed underwater. 


The U.S. Navy first improved the hull design to make American submarines better swimmers. The first steps in the GUPPY program was to  remove the extraneous objects that created drag, including deck guns, open periscope shears, and broad decking. The early GUPPY conversions, which included the Tang-Class submarines, maintained the World War II-era submarine shape, which had its problems, such as drag, trapped air bubbles, and cavitation (the collapsing of air bubbles making noise).  Thus, designers revisited the Type XXI design, and developed a “tear top” or blimp shape hull. This new structure had no prominent decking. From the conning tower, - or sail* - of the submarine, it tapered off into a rounded conical shape. The bow was more bulbous, whereas the aft tapered down a single propeller shaft. The other significant change was a single hull design instead of a double.  [Double hull designs have the ballast tanks on the outside of the submarine superstructure, making a second hull. Single hull designs, however, have ballast tanks on the inside of the primary hull structure.] The result was a hydrodynamic hull that was more efficient underwater than on the surface.


* [Terminology NOTE: During World War II, submarines had a command and control work area inside the large dorsal fin. The bridge and periscopes in this area was called the Conning Tower. Post-war improvements moved the command and control area below decks, and it was called the Control Room.  The now empty dorsal fin structure that included the bridge and periscopes became known as the sail.]


The “tear-drop” shape led to two other significant changes.  The large “drop” bow now housed a large spherical SONAR hydrophone array. Older submarines with hydrophones installed on the bottom of the vessel could only scan forward and aft; the spherical hydrophone allowed the sub to be more multi-directional.  With the SONAR array in the bow, this forced the forward torpedo room to be shifted to midship. The other advantage to the “tear-drop” shape was more effective management of water pressure. Combined with advances in metallurgy, these innovations produced submarines with greater operating depths than their World War II counterparts.  


The next major change to construction involved the power plant of the submarine. From 1912 to 1956, the primary propulsion of a submarine was the diesel-electric drive. As effective as these submarines were, their critical flaw was their limited speed and time submerged. Prior to the German and Japanese innovations to battery storage, most submarines could move at 2-3 knots for several hours or as high as 8-9 knots for an hour before the batteries would drain. Following their innovations, the speed increased as high as 20 knots, but still could not be maintained for more than an hour. The batteries also presented safety concerns due to their large, lead acid cells that had the potential to emit unstable hydrogen gas through electrolysis, or deadly chlorine gas if introduced to saltwater. The Navy sought to create a safer vessel, as well as to develop a true submarine that could operate submerged for indefinite periods of time. At the end of World War II, the dawn of the nuclear age offered the promise of unlimited power. The primary concern involved containing the awesome potential of atomic energy in a safe and sustainable power plant. 


The desire for a self-contained portable nuclear reactor that could be fitted aboard a submarine emerged as early as 1946.  Admiral Hyman Rickover, then a Captain, was placed in charge of the nuclear program under the Bureau of Ships to develop safe, ship-sized nuclear reactors. The program produced a reactor that could operate more than just propulsion. It also powered air exchangers and other electrical systems for a seemingless unlimited amount of time.  His project created the USS Nautilus (SSN 571), the first nuclear submarine, in September 1954. The Nautilus, though carrying a nuclear reactor, still looked like a diesel-electric GUPPY submarine with a flat deck and low freeboard. This design was maintained in the next few experimental boats, such as the USS Seawolf (SSN 575) and the Skate-class (SSN 578-579 and SSN 583-584).  The first fast-attack submarine class to combine the “tear-drop” shape with a nuclear reactor was the Skipjack-class (SSN 585-SSN 592) in 1959. From the Thresher/Permit-class commissioned in 1961 to the Los Angeles-class commissioned in 1976, there were new innovations introduced that made each new class of fast-attack submarine quieter, more efficient, deeper diving, and deadlier hunter-killers.


The fate of diesel-electric boats was sealed in 1956 when Chief of Naval Operations, Admiral Arleigh A. Burke announced that the US Navy was no longer going to invest in the development of diesel-electric boats and focusing instead on nuclear-powered submarines. This made the Tang-Class subs, the Sailfish-Class of RADAR Picket subs, the USS Grayback Guided-missile sub, and the “tear-top” shaped Barbel-Class subs built between 1949 and 1957, the last of the diesel-electric sub of the United States Navy.  Although they stopped building diesel-electric submarines, many remained in service for several decades. The last of the Barbel-class were decommissioned in the 1990’s.


Researching the material aspects of the last diesel-electric boats and the early nuclear sub is similar to the procedures discussed in Part I of this series. In Record Group 19: Records of the Bureau of Ships, there are several relevant series. . They include correspondence arranged according to the 5th Edition of the Navy Filing Manual (1950) and - for a brief period in 1960 and 1961 - the current Standard Subject Identification Code (SSIC) filing manual, which was introduced in 1960. 


There is a disruption in the continuity of the Unclassified Correspondence between 1962 and 1965. The Navy began to index the correspondence and no longer arranged it by the SSIC filing system. The indexing was not intuitive and did not follow a pattern that would allow a researcher to pinpoint specific records.  Additionally, the index for this series was determined to be a temporary record and disposed, .Ultimately, the 1962, 1963 and 1964 Unclassified Correspondence were also determined as disposable, because they were not easily accessible.  The 1965 Unclassified Correspondence was retained, and contains  differences in the filing systems. There are some gaps in correspondence in higher classifications, but not as many as during the mid-1960’s for the Unclassified Correspondence.


Unclassified General Correspondence: 1954, 1955, 1956, 1957, 1958, 1959, 1960, 1961, 1962, 1965

Confidential General Correspondence: 1954, 1955, 1956, 1957, 1958, 1959, 1960, (1960-62), 1961, 1962

Secret General Correspondence: (1947-1966), 1954, 1955, 1956, 1957, 1958, 1959, 1960, 1961, 1962, 1964


[Please NOTE: As you review the various Catalog entries on these topics that the entries mentioned in this blog may be still classified for various reasons including for containing Restricted Data (RD) and Formerly Restricted Data (FRD).  Please check the “Access Restriction(s)” section of each of the Catalog entries and that if you are interested in these records that you should follow the guidance on filing a Freedom of Information Act request]


In using correspondence from the 1950s to 1961, you can use similar methods as those described in Part I.  However, you should note the additional designation prefix “SSN” for nuclear submarine, or “fast-attack” submarine.


In addition to the general correspondence series, there are specific series on particular submarines, submarine classes, and submarine systems. For example, there are series on the Nautilus and Skate-class submarines: Correspondence for USS Nautilus , Nuclear Power Plant Diagrams, and Test Reports, 1953 - 1958; Technical Manuals and Related Records for SSN 571-578 part of [Central Correspondence Enclosures]; and U.S.S. Skate (SSN 578) Report of Patrol Number One (Entry UD-WW 39 - No NAID).  Series exist on hull forms, construction, and other systems: Central Correspondence Enclosures 1945-1965; Submarine Reports, 1929-1965; and General Correspondence Relating to Submarine Sonar Systems, 1956 - 1965.  [A note on Submarine Reports (UD 1022-W2): the title is misleading and does not include “patrol” reports, but reports on various ship constructions, hull forms, and machinery arrangement of submarines and other types of ships.]


We also have records on the other two classes constructed during the later period of the Bureau of Ships: the Skipjack-Class (SSN 585-SSN 592) and Permit/Thresher-Class (SSN 593-596; SSN 603-607; SSN 612-615; SSN 621). Most of the information and records on these classes are covered in the Correspondence.


The Bureau of Ships records in Record Group 19 ended in 1966 when the bureau was reorganized into the Naval Sea Systems Command (Record Group 344).


The Unclassified Correspondence of both the Naval Sea Systems Command and the Naval Ship Engineering Center (NAVSEC) are divided into incoming and outgoing correspondence. They are not arranged by Navy Filing Manual or the Standard Subject Identification Code (SSIC).  The incoming correspondence is arranged by the date of correspondence. The outgoing correspondence uses the category system that was developed by the Bureau of Ships in the early 1960’s, as reflected in the 1965 correspondence. It is arranged using these letter categories A, C, D, E-R, N, and S, SS, Y, and then arranged by date. There is a rudimentary relationship between the category letter and the correspondence about a type of ship. For example, the majority of material on submarines should be in the “S, SS, Y” segment. “SS” covers all submarine topics including nuclear fast-attack (SSN) and nuclear ballistic missile (SSBN) subs, as well as conventional boats (SS). However, because of the generalized category system and correspondence being arranged by date, it may be challenging to determine if there is correspondence about the particular boat you are interested in. It is important to note that there may be a minority of correspondence spread out across the other categories about subs, depending upon how the correspondence was categorized.


Because there is not a key to the category designations in these series that were used by the Bureau of Ships and the Naval Sea Systems Command, the National Archives cannot properly navigate these records and advise the public where there is specific information on shipyards, private companies, or shipborne systems.


Unclassified Correspondence (Incoming)

1968, 1969, 1970, 1971


Unclassified Correspondence (Outgoing)

1966, 1968, 1969, 1970, 1971


Unclassified Serial Correspondence Files of the Naval Ship Engineering Center (NAVSEC) (Incoming)

1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976


Unclassified Serial Correspondence Files of the Naval Ship Engineering Center (NAVSEC) (Outgoing)

1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977


Central and Contract Records Branch Ships

Official Subject Files, 1967


In NAVSEA records, there are some series on specific classes of submarines as well as series that cover a broad period of time.  One series covering several classes is Nuclear Powered Attack Submarine (SSN) Maintenance Case Files [Maintce Day C79 C84], Secret Subject Files, 1966-1970 and Ship Design Project Files, 1969-1974


The two main classes of fast-attack submarines developed during the period of NAVSEA are the Sturgeon-class (SSN 637-639; SSN 646-653; SSN 660-687) and the Los Angeles-class (SSN 688-725; SSN 750-773).


Here is a select list of series related to Sturgeon-Class:


Sturgeon Class (SSN 637) and USS Glenard P. Lipscomb (SSN-585) Nuclear Powered Attack Submarine Project Files [CORRES C84]


Sturgeon Class Nuclear Powered Attack Submarine (SSN 637) Project Files [SUBM CASE FILES C84   73]


Overhaul Correspondence Files for Sturgeon Class Nuclear-Powered Fast Attack Submarines (SSN 637)


And here is a select list of series related to Los Angeles-Class:


Los Angeles-class Nuclear-Powered Fast Attack Submarine (SSN 688) Hull and Weapons Development Files [Hull and Weapons Branch, Submarine Ship Acquisition Project Management Office, Fast Attack Class (SSN699) Submarine Design and Technical Files]


Los Angeles-class Nuclear-Powered Fast Attack Submarine (SSN 688) Development Files [Submarine Directorate (NAVSEA 92), Attack Submarine Acquisition Project (PMS 393)]


Correspondence Regarding all Phases of the Construction and Delivery of Los Angeles-class Nuclear-Powered Fast Attack Submarine (SSN-688)


Los Angeles Class Nuclear Powered Attack Submarine (SSN 688) Design Studies and Task Descriptions [SEA PMS 393 Ship Case Files]


Submarine Files [ SSN-688 Class Project Files;  {SHIPS PMS393 SHIP CASE FILE C81/83 75}]


Operational records of submarines during this period can appear confusing. As previously mentioned, Record Group 313 is a good resource for submarine records at the National Archives. After 1954, however, series of theater commands, theater submarine forces, and some individual submarine commands are inconsistent in continuity. There are discontinuous periods of record with gaps. Additionally, for the more recently accessioned records, regardless of their actual classification, will be held as classified records awaiting a second review before being released. In short, like with the Bureau of Ships and Naval Sea Systems Command records, even though series appear in the Catalog, they may not be immediately available, so check the “Access Restriction(s)” section of the Catalog entry for availability.   For those familiar with them, there is a portion of RG 313 defined by Red and Blue Folder numbers. The colors and numbers pertain to a particular series of administrative records from a specific command. There is usually a dossier file associated with the color/number folder, which could be a general container list of Navy Filing Designations or a specific folder list. These records are generally dated through1961. There have been recent accessions, but many are classified, and the accessioning paperwork is not very descriptive. The series COMSUBPAC Primary Program records, 1968-76, which one might think would contain valuable operational records for Vietnam era submarines, only has general administration records (SSIC 5000-5999) and ships material correspondence (SSIC 9000-9999). It does not appear to include any operational records (SSIC 3000-3999 specifically SSIC 3800: Submarine Patrol Reports). 


Record Group 313 is still open and the National Archives is receiving a new series of records for different naval commands including submarine commands. Being new arrivals, it will be some time before series get declassified (if that is necessary), processed and described.  As information becomes available for newly received records of submarine commands, we will update this portion with new information on these series.


In Record Group 38, Records of the Chief of Naval Operations, the Entry UD-UP 11-B (Records Regarding Pacific Area Naval and Fleet Operations, 1966-1970) contains monthly reports from the Commander-in-Chief, Pacific Fleet, reports on Operation Market Time, and submarine surveillance reports of Soviet and Chinese shipping in the South China Sea and the Gulf of Tonkin.  However, the brief reports contain more information about the foreign shipping traffic than the American submarines making the reports.


RG 38 also includes Entry UD-09D 24: Post-1946 Submarine Patrol Reports. As mentioned in Part I, this series contains submarine patrol reports dated through 1958. The reports are mainly from the diesel-electric submarines (SS), with a few from missions to the Arctic by early nuclear submarines like the Nautilus and Skate. However this series is incomplete for the remaining years of the Cold War, and does not contain reports on the numerous patrols made by diesel-electric and nuclear fast-attack submarines. Unlike the World War II and the Korean War patrol reports, there is not a set of patrol reports for the rest of the Cold War and the Vietnam War.  

You may use the NARA Catalog to search for “submarine” topics by refining your search to RG 38 or RG 313 and “series.” If you have further questions about searching the Catalog, email


For Command Operational Reports, Command Histories, Patrol Reports, and other records held outside of the National Archives, the Naval History and Heritage Command is a repository for Cold War and Vietnam War era submarine records.  Command Operational Reports (COR) and Command Histories are annual reports of the ship’s activity. These reports were established in 1964 and maintained through the rest of the Cold War. There were some earlier command histories, but prior to the escalation to the Vietnam War in 1964, regular reporting was not required. The command histories and COR list the location and activities of the ship or sub throughout the year. However, apart from stating the beginning and ending ports and dates for the patrolhe histories, they do not disclose where and what the submarine was doing while on the actual patrol.


There are select patrol reports in the Naval History and Heritage Command’s Vietnam Command Files. These include: the USS Bashaw (LPSS 241) July 1967 report, USS Perch (LPSS 313) in Operation Dagger Thrust IV in December 1965 USS Pickerel (SS 524) January 1967 report, USS Sabalo (SS 302) report on operations for 1969 to 1971, USS Salmon (SS/AGSS 573) reports on operations in 1966 and 1969, and a report from Submarine Flotilla Seven.

For further questions on records on Cold War Submarines in the post-Korean War period, you may contact the Naval History and Heritage Command:


Operational Archives

Naval History and Heritage Command

805 Kidder Breese Street SE

Washington Navy Yard, DC 20374-5060

(202) 433-3224; Fax (202) 433-2833