Skip navigation

At the conclusion of World War II, the political landscape shifted from suppression of aggressive fascist regimes to the threat of Soviet communist influence over war torn Allied occupied countries, and territories still under colonial rule calling for liberation. As the United States and the Soviet Union began to square off on land, a larger, more unseen conflict developed under the surface of the ocean.  Similar to both world wars, the US primarily defended against foreign invasion at sea, and the Soviets made ample preparations for confrontation. They armed themselves with newly acquired technologies from the defeated Germans, and began to assemble a large navy with primary investments in undersea warfare. Submarine forces on both sides were near war footing for most of the Cold War, consisting of  quieter and more imperceptible ships, armed with deadlier weapons as part of the booming nuclear deterrence.


This is the first installment of a four part series on the records of Cold War Submarines. It will describe the period from 1946 to 1958, from which there are many records available for research. The second part will discuss nuclear age records of US fast-attack submarines (SSNs) and the height of the Cold War, and the recordkeeping issues with this period. The third part will discuss the development of the Fleet Ballistic Missile submarine (SSBN) and currently available records. The final portion will discuss submarine deck logs for the whole Cold War and the changing landscape of available information.


This chapter of submarine history has two distinctive periods with very different availability of records. Unfortunately, there is no one year when the line is drawn, so there may be some overlap depending on the record group, entry, or government agency.


From the end of World War II to about the mid-1950’s, the US evaluated the successes of their Pacific submarine campaign and their Atlantic Anti-submarine campaign to prepare for future conflicts. They experimented in the creation of various submarine types, including troop transports (ASSP/LPSS), fuel tankers (SSO), RADAR picket (SSR), and guided-missile submarines (SSG). These experimental developments were drawn in part from wartime experiences. They also studied innovations in submarine technology developed by the defeated Germans and Japanese.


By the end of World War II, both Germany and Japan made great strides in developing better submarines that were faster submerged, had more combat capabilities, and were harder to detect even with newer SONAR systems. The Germans developed a snorkel, which enabled their submarines to use diesel engines at periscope depth, giving them greater speed than their American or British counterparts.  The Germans and Japanese experimented with larger battery wells and newer hydrodynamic hull designs to allow submarines to move more efficiently underwater and dive deeper.  They also both experimented with sound absorbing coatings to make submarines less detectable by absorbing active SONAR waves. The Germans developed more sensitive passive SONAR equipment that could hear targets or threats at greater distances. The Japanese developed huge aircraft carrying submarines that had the potential to carry out stealthy air raids.  The most important innovations included the Germans Type XXI and the Japanese I-200 (Sen Taka) submarines. These became the basis for future designs during the Cold War. They were distinguished by enhanced hydrodynamic hulls that were quieter, deeper diving, and capable of tracking potential targets or threats at greater distances, which made the anti-submarine warfare (ASW) practices at the time obsolete.


The records of the evaluations of enemy technology can be found in the Naval Technical Mission Reports for Germany and Japan. There are other series related to Tambach Files, captured records on German technological developments in Record Group 38 and in Record Group 242, which include German submarine developments like the snorkel, passive SONAR, and hydrogen peroxide propulsion.


For Japanese submarine technology, there are other reports, specifically from Submarine Squadron 20, who evaluated the Japanese submarines that surrendered in Tokyo Bay. These included the mammoth aircraft carrying I-400’s and the I-14 in the World War II Command Files and the Flag File Screening Documents. Also, the final reports of the Naval Technical Mission to Japan (NTMJ) include an evaluation of Japanese Submarines (S-17) and other submarine systems and ordnance (S-19).


The other large group of records on the Navy’s evaluation of enemy technology can be found in Record Group 19: Records of the Bureau of Ships in correspondence files, which are arranged using the Navy Filing Manual.  The filing designations that would be helpful would be the country designations for Japan and Germany, which are EF30 and EF37 respectively. There is also a filing designation for captured enemy equipment - EF74. The filing designation for correspondence about submarines, in general, is “SS”. In pairing the different filing designations, files on German submarines are under EF30/SS and files on Japanese submarines are under EF37/SS. These files can be found in the General Correspondence, 1940-45 under the EF 30, EF37 and EF74 segment and the SS segment of the series, the Bulky Enclosures to the Bureau of Ships Correspondence and the Confidential Correspondence, 1946.


In the finding aids for general and confidential correspondence from 1940 to 1946, there are several topics relating to submarines that can be researched using the filing designation “SS”.  You can also reverse the filing designation from EF30/SS to SS/EF30.  But to research innovations in propulsion or other submarine systems in the post-war period, you will need to find the corresponding filing designation. For example, correspondence on developments in propulsion are filed under SS/S41-1 (with S41-1 designating main propulsion).  For other ship related developments, check the S-Section of the manual for filing designations for Ship’s Material.


You may find additional materials on the evaluation of enemy submarines prior to 1947 that later contributed to Cold War developments in Record Group 313: Records of Naval Operating Forces. Listed below are potential series in RG 313 for the Commander, Submarine Forces, Atlantic Fleet (COMSUBLANT) and Commander, Submarine Forces, Pacific Fleet (COMSUBPAC) that may have more materials on the evaluation of enemy submarine technology. 



A1 275 Organizational, Operational, Instructional, and Communication Records

UD 1278 Confidential and Unclassified General Administrative Files

UD 2064 Secret General Administrative Files



UD 2015 Secret Serial Files

UD 1274 Secret Serial Files

P 53 Secret Serial Files

P 57 Top Secret General Administrative Files

A1 222 Confidential, Restricted, and Unclassified General Administrative Files

P 58 Confidential General Administrative Files

P 49 Confidential, Restricted, and Unclassified Administrative Files 

P 46 Confidential, Unclassified & Restricted General Administrative Files

UD 2041 Secret Correspondence Files


These files may contain valuable information, because the Navy relied on the opinions and practical experience of the submarine personnel who had been at sea, in addition to the naval architects and engineers from the Bureau of Ships. In COMSUBLANT, Submarine Squadrons 6 and 10 helped evaluate captured German U-Boats like the Type XXIs, U-2513 and U-3008. On the Pacific side, for COMSUBPAC, Submarine Squadrons 13 and 20 helped evaluate captured Japanese submarines.  Submarine Squadron 13 evaluated the Japanese I-200s (Sen Taka), the Japanese equivalent to a German Type XXI with a streamline hull and larger battery capacity for greater speed and longer endurance submerged. Submarine Squadron 20 helped evaluate the monstrous aircraft carrying I-400s (Sen Toku) that carried three high-speed armed float planes.


As the United States evaluated innovations from captured enemy submarines, the Soviet Union also evaluated captured German submarine technology. The Soviets wanted to make immediate use of this new technology and planned to expand their Navy to include a large submarine arm.  The Soviet submarine force became equipped with hundreds of German Type XXI copied subs that would become the Zulu, Romeo, and Whiskey-classes of attack submarines.  The prospective threat of a large Russian submarine force convinced the NATO navies to rethink their anti-submarine strategies. The US Navy assessed that the Soviet submarine threat was so great that all service arms needed to be included in the new anti-submarine effort. To this end, the US Navy wanted to utilize existing submarines and developed a new class of ASW Hunter-Killer submarines (SSK) to be completed by 1955.


Therefore, the US Navy updated existing World War II-era submarines with German and Japanese wartime innovations. This program was called the Greater Underwater Propulsion Power or GUPPY.  The GUPPY program gave US subs increased underwater speed, endurance, and stealth, which were all necessary for the SSK goal.  However, to be a good hunter-killer, these vessels needed to be able to both locate and attack their quarry sailing at depth. During the same period, the US Navy experimented with copies of the German Gruppenhorchgerät (GHG) passive SONAR set to locate possible enemy submarines. During the late 1940’s and 1950’s, the US Navy tested passive SONAR sets and how to use them during Project Kayo. The goals of the project were two-fold: to make recommendations for the new Hunter-Killers, and to create a manual for existing GUPPY converted World War II-era submarines to follow in the meantime, until the new SSKs come online. 


Correspondence in Record Group 19: Records of the Bureau of Ships, 1940-1966 includes a series of records for each year. To find information on these programs, use the filing designation of “SS” for general submarines and SS### for any specific submarine.  If you are looking for information on specific classes of submarines like the Tang-class or the Hunter Killers, look under SS563-Class or SSK1-Class. These were the first purposely built GUPPY submarines.  The boats of the Tang-class were numbered SS563 to SS568.


Unclassified General Correspondence: 1947, 1948, 1949, 1950, 1951, 1952, 1953, 1954 and 1955

Confidential General Correspondence: 1947, 1948, 1949, 1950, 1951, 1952, 1953, 1954, and 1955

Secret General Correspondence: 1947, 1948, 1949, 1950, 1951, 1952, 1953, 1954, and 1955


[Please note that with Confidential and Secret General Correspondence series in later periods, there may be more restricted classified records that you may need to request under the Freedom of Information Act.]


Record Group 19 also includes several non-correspondence series that relate to submarine development during the Early Cold War Period. These include Entry P 37: Preliminary Design Books, 1904 - 1957, Entry P 62: Records Related to Ship Hull Design, 1940 - 1966, and Entry P 13: Submarine General Information Books and Related Documentation , 1913 - 1961. Another series exists in Record Group 344: Records of Naval Sea Systems Command, Entry P 11-D: Ship Information Books and Related Documentation - Submarines, 1914 - 1978.


In addition to the SSK Hunter Killer Submarines, the Navy began to upgrade and develop submarines for different missions like the Submarine Transport (SSP), Submarine RADAR Picket (SSR), Submarine Fleet Oiler (SSO), and Submarine Guided Missile (SSG). The USS Perch (ASSP 313) and USS Lionfish (ASSP 315) were developed into submarine transports.  The Navy modified each boat under the GUPPY program.  They removed the torpedo tubes to make room for troops. They added a watertight container aft of the sail to hold equipment which was large enough to house an amphibious tractor. The USS Guavina (ASSO 362) was refitted into an oiler. Several submarines were converted into RADAR pickets, including USS Burrfish (SSR 312) and USS Rasher (SSR 269). Starting in 1946, they were converted under the Migraine programs I to III so that the aft torpedo rooms were removed to expand the Combat Information Centers (CICs) and add new RADAR equipment. You may find records on the development of these offshoots and the guided missile submarine (SSG) in the correspondence files in Record Group 19. With the exception of the transport submarines, these experimental variations had limited service lives as new technologies made them obsolete.


On the topic of guided missile submarines, the US Navy first fired small rockets at shore establishments during World War II when the USS Barb (SS 220) attacked Japanese facilities. This led to developing the first guided missile submarine (SSG), borrowing the German’s V-1 “Buzz Bomb,” and Japanese innovations of watertight above deck storage compartments.  Project Loon began in the late 1940’s. These programs led to Projects Regulus and Regulus II, which were built on the same concept but improved the missile and changed the warhead from conventional to nuclear. In Record Group 72: Records of the Bureau of Aeronautics are the chapters and background notes to Admiral D. S. Fahrney’s History of Pilotless Aircraft and Guided Missiles.


The National Archives in College Park also maintains operational records for submarines during the Early Cold War. In particular, the Korean Conflict was an example of the pivot from World War II’s unrestricted global submarine warfare to a maritime policy of limited regional war. At the outset of the Korean Conflict in June 1950, the US and the Western Allies were anxious that the conflict was just the opening act to World War III. The few submarines based in Japan and Pearl Harbor were rigged with a full war load of torpedoes and deployed to the waters neighboring Korea to look for Soviet ships.  Unlike in World War II, the submarines of the Far East Command were instructed to observe and await further orders. What concerned the US Navy was the 50 to 60 reported submarines in Vladivostok, Russia. As the conflict continued, the mission for US submarines became the surveillance of Soviet and Chinese shipping in the East China Sea and the Sea of Japan.


These reports, as well as other pre-Korean and post-Korean Conflict submarine reports can be found in Record Group 38 in the post-1946 Submarine Patrol Reports. This collection of post-World War II patrol reports include operational reports for US submarines during the period of the evaluation of enemy technology. It includes US utilization of that technology in new types of classes (1946-1950), the Korean Conflict (1950-54), and some post-Korean patrols (1954-59).  The series includes reports of diesel-electric submarines (SS) with a few reports from early nuclear submarines (SSN) and one endorsement for a nuclear ballistic submarine (SSBN).  This is not the main body of records for nuclear fast-attack or ballistic submarines, but this will be discussed in the next installment.


Another source of operational records during the Korean Conflict and continuing through 1958-59 are in Record Group 313. In addition to the submarine commands, there may be other files relating to submarine missions under other types of commands, depending on the mission.  For example, there are training reports of US Marines and the Royal Marine Commandos aboard the USS Perch (ASSP 313) prior to and during the early part of the Korean Conflict in the Commander, Amphibious Forces, Pacific. There may be additional  records under other commands, like fleets or service forces.


This concludes the first part of this topic. The next segment will discuss the records of the Cold War Submarines from 1954 to 1992 with the advent of nuclear power and the development of fast-attack submarines (SSNs), and the problems that arise with pertinent records.