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

Imperial Japanese Navy

The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...

and merchant marine shipping losses caused by U.S. and Allied forces during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

Background

In January 1943, JANAC was formed by General

General (United States)

In the United States Army, United States Air Force, and United States Marine Corps, general is a four-star general officer rank, with the pay grade of O-10. General ranks above lieutenant general and below General of the Army or General of the Air Force; the Marine Corps does not have an...

George Marshall

George Catlett Marshall was an American military leader, Chief of Staff of the Army, Secretary of State, and the third Secretary of Defense...

, the Chief of Staff of the U.S. Army

Chief of Staff of the United States Army

The Chief of Staff of the Army is a statutory office held by a four-star general in the United States Army, and is the most senior uniformed officer assigned to serve in the Department of the Army, and as such is the principal military advisor and a deputy to the Secretary of the Army; and is in...

, and Admiral

Admiral (United States)

In the United States Navy, the United States Coast Guard and the United States Public Health Service Commissioned Corps, admiral is a four-star flag officer rank, with the pay grade of O-10. Admiral ranks above vice admiral and below Fleet Admiral in the Navy; the Coast Guard and the Public Health...

Ernest J. King, the Chief of Naval Operation 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 chaimanship of Rear Admiral

Rear admiral (United States)

Rear admiral is a naval commissioned officer rank above that of a commodore and captain, and below that of a vice admiral. The uniformed services of the United States are unique in having two grades of rear admirals.- Rear admiral :...

Walter DeLaney. Following the war, Rear Admiral Jerauld Wright

Jerauld Wright

Admiral Jerauld Wright, USN, served as the Commander-in-Chief of the U.S. Atlantic Command and the Commander-in-Chief of the U.S...

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
Strategic bombing survey
The United States Strategic Bombing Survey was a board tasked with examination and analysis of the United States' involvement in the World War II. Its primary purpose was to determine the effectiveness of Allied, and more specifically American, strategic bombing campaigns in Europe and in Asia...

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.

Sinking Agent	Naval Vessels		Merchant Vessels		Total Vessels
Sinking Agent	No.	Tonnage	No.	Tonnage	No.	Tonnage
*TOTALS*:	686	1,965,646	2,346	8,618,109	3,032	10,583,755
*United States (U.S.):*	611	1,822,210	2,117	7,913,858	2,728	9,736,068
Submarines	201	540,192	1,113	4,779,902	1,314	5,320,094
Surface Warships	112	277,817	11	43,349	123	321,166
Carrier Aircraft	161	711,236	359	1,390,241	520	2,101,477
Land-based Navy-Marine Aircraft	11	13,402	88	218,718	99	232,120
Army-Navy-Marine Aircraft	9	48,750	23	114,306	32	163,056
Navy Shore Batteries	2	2,770	—	114,306	2	2,770
Mines	19	17,995	247	591,660	266	609,655
Aircraft and Other Agents	26	147,883	32	132,710	58	280,593
Unknown Agents	—	—	4	3,305	4	3,305
*Allied Forces:*	45	69,636	73	211,664	118	281,300
United Kingdom (U.K.)	28	50,365	42	87,981	70	138,346
Netherlands	7	8,099	15	57,471	22	65,570
Australia	5	6,892	8	24,910	13	31,802
China	—	—	3	14,327	3	14,327
Soviet Union	2	1,660	2	8,233	34	9,893
New Zealand	2	2,095	—	—	2	2,095
Netherlands and Australia	—	—	2	8,303	2	8,303
Netherlands and India	—	—	1	10,439	1	10,439
Australia and India	1	525	—	—	1	525
*U.S. and Allied Forces*:	10	14,864	12	57,923	22	72,787
U.S. and Australia	4	7,550	7	37,072	11	44,622
U.S., Australia, and Netherlands	—	—	2	16,362	2	16,362
U.S. and U.K.	5	5,102	2	3,500	7	8,602
U.S. and New Zealand	1	2,212	—	—	1	2,212
U.S., U.K., and Netherlands	—	—	1	989	1	989
*Marine Casualties*:	13	50,338	97	268,948	110	319,286

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

Vice admiral (United States)

In the United States Navy, the United States Coast Guard, the United States Public Health Service Commissioned Corps, the National Oceanic and Atmospheric Administration Commissioned Corps, and the United States Maritime Service, vice admiral is a three-star flag officer, with the pay grade of...

Charles A. Lockwood

Charles Andrews Lockwood was an admiral of the United States Navy. He is known in submarine history as the legendary commander of Submarine Force Pacific Fleet during World War II...

and his COMSUBPAC

ComSubPac

Commander Submarine Force, U.S. Pacific Fleet is the principal advisor to the Commander, United States Pacific Fleet for submarine matters. The Pacific Submarine Force includes attack, ballistic missile and auxiliary submarines, submarine tenders, floating submarine docks, deep submergence...

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.

Ship	JANAC figures			Wartime Estimates
Ship	War Patrols	Ships Sunk	Tonnage	Ships Sunk	Tonnage	Tonnage Diff.
	6	21½	104,564	23½	153,800	0.65
	8	18	99,901	19	137,200	0.73
	12	17 1/3	97,579	28	197,900	0.48
	5 (lost)	24	93,824	31	227,324	0.41
	14	23	90,080	26	143,700	0.63
	5	21	88,091	21	122,7900	0.63
	12 (lost)	18 1/3	89,892	25⅓	183,900	0.47
	13	15	80,580	19	118,000	0.68
	9	15	76,687	17	115,000	0.67
	9 (lost)	17	75,473	16	105,800	0.71

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

Commanding Officer	JANAC figures			Wartime Estimates
Commanding Officer	War Patrols	Ships Sunk	Tonnage	Ships Sunk	Tonnage	Tonnage Diff.
Richard H. O'Kane	5	24	93,824	31	227,800	0.41
Slade D. Cutter Slade Cutter Slade Deville Cutter was a career U.S. naval officer who was awarded four Navy Crosses and tied for second place for Japanese ships sunk in World War II...	4	19	71,729	21	142,300	0.51
Dudley W. Morton Dudley W. Morton Dudley Walker Morton was a submarine commander of the United States Navy during World War II. He was commander of during its third through seventh patrols. Wahoo was one of the most-celebrated submarines of World War II, sinking at least 19 Japanese ships, more than any other submarine of the time...	6 (killed in action)	19	54,683	17	100,000	0.55
Eugene B. Fluckey Eugene B. Fluckey Rear Admiral Eugene Bennett Fluckey , nicknamed "Lucky Fluckey", was a United States Navy submarine commander who received the Medal of Honor during World War II.-Early life and career:...	5	16⅓	95,360	25	179,900	0.53
Samuel D. Dealey Samuel David Dealey Samuel David Dealey was a United States Navy submarine commanding officer during World War II. He was among the most decorated naval officers of the war, receiving six awards for valor including the Medal of Honor for his actions aboard the during her fifth war patrol.-Early Life and...	6 (killed in action)	16	54,002	20½	82,500	0.65
Reuben T. Whitaker	5	14½	60,846	18½	111,500	0.55
Gordon W. Underwood Gordon Waite Underwood Captain Gordon Waite Underwood was a United States Navy Captain who was awarded the Navy Cross for his achievements during World War II. He is the namesake of the ship USS Underwood .-Early life:...	3	14	75,386	14	89,600	0.81
Royce L. Gross	7	14	65,736	13½	80,500	0.82
Charles O. Triebel	8	14	58,837	13	83,330	0.71
John S. Coye, Jr.	6	14	38,659	14	71,700	0.54

Although JANAC tended to revise downward wartime esimates, one noteworthy exception involved the fifth war patrol of Archerfish (SS-311) under the command of Commander

Commander (United States)

In the United States, commander is a military rank that is also sometimes used as a military title, depending on the branch of service. It is also used as a rank or title in some organizations outside of the military, particularly in police and law enforcement.-Naval rank:In the United States...

Joseph F. Enright

Joseph Francis Enright was a submarine captain in the United States Navy...

. Archerfish was credited with sinking a 28,000-ton Hiyō-class aircraft carrier

Hiyo class aircraft carrier

The were built for the Imperial Japanese Navy during World War II. Both ships of the class were originally laid down as luxury passenger liners before being acquired by the IJN for conversion to aircraft carriers in 1941. Junyō was the first of the sisters to be completed in May 1942 and the ship...

during the war, but JANAC determined he had actually sunk the 59,000-ton carrier Shinano

Japanese aircraft carrier Shinano

named after the ancient Shinano Province, was an aircraft carrier of the Imperial Japanese Navy during World War II. Initially laid down as the third of the battleships, Shinano′s partially complete hull was converted to an aircraft carrier in 1942, midway through construction. Over the next two...

, 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 Japaneses aircraft carriers Kaga

Japanese aircraft carrier Kaga

Kaga was an aircraft carrier of the Imperial Japanese Navy , named after the former Kaga Province in present-day Ishikawa Prefecture...

, Akagi

Japanese aircraft carrier Akagi

Akagi was an aircraft carrier of the Imperial Japanese Navy , originally begun as an . She was converted while still under construction to an aircraft carrier under the terms of the Washington Naval Treaty...

, Hiryū

Japanese aircraft carrier Hiryu

was a modified Sōryū-class aircraft carrier of the Imperial Japanese Navy. She was one of the carriers that began the Pacific War with the attack on Pearl Harbor...

, and Sōryū

Japanese aircraft carrier Soryu

was an aircraft carrier of the Imperial Japanese Navy. During the Second World War, she took part in the attack on Pearl Harbor, Wake Island, Port Darwin and raids in the Indian Ocean before being sunk at the Battle of Midway.-Design:...

during the Battle of Midway

Battle of Midway

The Battle of Midway is widely regarded as the most important naval battle of the Pacific Campaign of World War II. Between 4 and 7 June 1942, approximately one month after the Battle of the Coral Sea and six months after Japan's attack on Pearl Harbor, the United States Navy decisively defeated...

by giving sole credit to the U.S. Navy.

External links

JANAC - HyperWar
Japanese Naval and Merchant Vessels Sunk During WWII By All U.S. Submarines - Valor at Sea: The U.S. Submarine War in the Pacific War 1941–1945
Ships and Tonnage Sunk or Damaged in WW II by U.S. Submarines - Pigboats.com
"Results of the German and American Submarine Campaigns of World War II" by Commander Michel Thomas Poirier, U.S. Navy (20 October 1999) - Chief of Naval Operations
Chief of Naval Operations
The Chief of Naval Operations is a statutory office held by a four-star admiral in the United States Navy, and is the most senior uniformed officer assigned to serve in the Department of the Navy. The office is a military adviser and deputy to the Secretary of the Navy...

- Submarine Warfare Division
Top Ten US Navy Submarine Captains in WW2 By Number of Confirmed Ships Sunk

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Background

Methodology & Results

Submarine service

Battle of Midway

See also

Primary Sources

Secondary Sources

External links