Joint Army–Navy Assessment Committee

Joint Army–Navy Assessment Committee (JANAC) was a United States inter-service agency set up to analyze and assess Japanese naval and merchant marine shipping losses caused by U.S. and Allied forces during World War II.

Background

In January 1943, JANAC was formed by General George Marshall, the Chief of Staff of the U.S. Army, and Admiral Ernest J. King, the Chief of Naval Operations and Commander-in-Chief, United States Fleet (COMINCH), to assess enemy naval and merchant shipping losses during World War II. The objectives of JANAC were as set forth in the following joint Army–Navy directive:

JANAC consisted of representatives of the U.S. Navy, the U.S. Army, and the Army Air Forces, with a joint Army–Navy secretariat, under the chairmanship of Rear Admiral Walter S. DeLany. Following the war, Rear Admiral Jerauld Wright succeeded Delany as JANAC chairman.

Methodology & results

JANAC used the following sources to compile information on Japanese vessel losses during World War II:

* Prisoner of War Reports
* Captured Enemy Documents
* United States and Allied Intelligence Sources
* Naval Shipping Control Authority for Japanese Merchant Marine (SCAJAP)
* Ariyoshi's Final List (Japanese)
* Ariyoshi's List (Japanese)
* Shipowners' List (Japanese)
* Naval Ministry List (Japanese)
* United States Mine Warfare Report
* United States and Allied Action Summaries
* United States Photographic Intelligence
* United States Strategic Bombing Survey (USSBS) Reports

The assessment of losses, unanimously agreed to by all JANAC members of the committee, was published in 1947, which included:

* All Naval vessels known or believed to have been lost.
* All merchant vessels of 500 or more gross tons known or believed to have been lost.

JANAC provided a detailed chronology of Japanese naval and merchant marine losses cross-indexed in the appendix of its final report, including a separate summary about losses caused by U.S. submarines. JANAC noted that a negligible number of vessels were not assessed because of insufficient information as to the cause of loss.

File:Pacific Theater Areas;map1.JPG, Pacific Theater of Operation (PTO)
File:Japanese Naval-Merchant Shipping Loses by Allied Forces - JANAC.svg, Japanese Naval and Merchant Shipping Losses by the Allied forces
File:Japanese Naval and Merchant Shipping Losses by the United States-JANAC.jpg, Japanese Naval and Merchant Shipping Losses by U.S. forces
File:US landings.jpg, PTO naval campaign

Legacy

Submarine service

JANAC significantly altered wartime estimates for Japanese losses inflicted by the U.S. Navy's submarine service. At the end of World War II, Vice Admiral Charles A. Lockwood and his COMSUBPAC staff had estimated that approximately 4,000 ships had been sunk, totalling 10 million tons lost. JANAC revised this total to 1,314 enemy vessels and 5.3 million tons sunk. JANAC estimates of Japanese losses revised wartime claims downward for most war patrols carried out by the submarine service during World War II as noted in the following table of the revised list of top ten submarines based upon the total tonnage sunk as determined by JANAC.

JANAC also revised the achievements of individual submarine commanding officers as noted in the following table.

Although JANAC tended to revise downward wartime estimates, one noteworthy exception involved the fifth war patrol of ''Archerfish'' (SS-311) under the command of Commander Joseph F. Enright. ''Archerfish'' was credited with sinking a 24,000-ton ''Hiyō''-class aircraft carrier during the war, but JANAC determined he had actually sunk the 66,000-ton carrier ''Shinano'', making this the most successful submarine patrol of the Pacific War.

Battle of Midway

JANAC also addressed wartime claims made by the U.S. Army Air Force regarding the sinking of the Japanese aircraft carriers ''Kaga'', ''Akagi'', ''Hiryū'', and ''Sōryū'' during the Battle of Midway by giving sole credit to the U.S. Navy.

See also

* Allied submarines in the Pacific War
* Strategic Bombing Survey

Notes

Bibliography

Primary Sources

*
* Special Research History – Navy Department Library – Naval Historical Center:
** SRH-163 - Joint Army–Navy Assessment Committee (JANAC), Miscellaneous Memoranda, 1943–1947
** SRH-164 - Memoranda from COMINCH, (F-20) to Joint Army–Navy Assessment Committee (JANAC), 1944–1945
** SRH-165 - Memoranda from Office of Naval Communications to Joint Army–Navy Assessment Committee (JANAC), 1943–1944
** SRH-166 - Joint Army–Navy Assessment Committee (JANAC), Memoranda to Office of Naval Communication
** SRH-167 - Memoranda from Army Signal Corps to Joint Army–Navy Assessment Committee (JANAC), 1945–1946
** SRH-168 - Agenda Minutes/Assessments, Joint Army–Navy Assessment Committee (JANAC)

Secondary Sources

* Clay Blair Jr. ''Silent Victory: The U.S. Submarine War Against Japan'' (Philadelphia: Lippincott, 1975) (Paperback)
* David M. Key Jr. ''Admiral Jerauld Wright: Warrior among Diplomats'' (Manhattan, Kansas: Sunflower University Press, 2001)
*

External links

JANAC report


- Valor at Sea: The U.S. Submarine War in the Pacific War 1941–1945


- Pigboats.com


- Chief of Naval Operations - Submarine Warfare Division
* ttp://ahoy.tk-jk.net/macslog/TopTenUSNavySubmarineCapt.html Top Ten US Navy Submarine Captains in WW2 By Number of Confirmed Ships Sunk
{{DEFAULTSORT:Joint Army-Navy Assessment Committee
Intelligence services of World War II
Pacific War
Joint committees