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John T. Kuehn is an Associate Professor of Military History and has served on the faculty of the U.S. Army Command and General Staff College since July 2000. Retiring after naval service in 2004, he earned a Ph.D. in History from Kansas State University in 2007. He is the author of Agents of Innovation (2008) and co-authored Eyewitness Pacific Theater (2008) with D.M. Giangreco, as well as numerous articles and editorials. In October 2009 he lectured Chief of Naval Operations Strategic Studies Group in Newport, Rhode Island, chaired by retired Admiral James Hogg. He recently was awarded a Moncado Prize from the Society for Military History in 2011 for “The U.S. Navy General Board and Naval Arms limitation: 1922-1937.” He is also an adjunct professor for the Naval War College Fleet Seminar Program and with the MA in Military History Program at Norwich University. A former naval aviator (flying in both EP-3 and ES-3 aircraft), he has completed numerous cruises aboard four different aircraft carriers. He flew reconnaissance and combat missions during the last decade of the Cold War, the First Gulf War (Desert Storm), Iraq and the Persian Gulf (Southern Watch), and the Balkans (Deliberate Force over Bosnia)

Editor’s Note: To augment his lesson on naval innovation in World War II, Commander Kuehn sent a request for a short summary (4 to 5 pages) of the WW II submarine campaign to Captain Peter Swartz of the Center for Naval Analyses. The request was forwarded to several possible sources, one of which was THE SUBMARINE REVIEW. That answer is next in this interesting interchange.

Commander Kuehn,

As with several others who have responded to your request for a 4 or 5 page summary of US Submarine Operations in World War II, I have to say I am not aware of any worthwhile summary of anywhere near that length. I do note, however, that you mentioned naval innovation as an interest so perhaps a few facts might help:

Roscoe’s book Submarine Operations in World War II published in 1949 by the Naval Institute in a tabular description of results gives these figures which describe the intensity of the effort31,571 days of submarine patrols in the op areas with a total of 1, 150 merchant ships sunk out of a total of 2,250 by all forces. This with 6% of the Navy’s personnel. Although the primary job for WW II US Subs was Commerce Raiding against Japanese Logistics, some other missions were squeezed in, often enroute to patrol areas:

A. Fleet Scouting- Some done but considered by Nimitz to be secondary to Unrestricted Submarine Warfare vs. Logistics
B. Fleet Interdiction- Phil Sea, Leyte Gulf
C. Special Force Operations- Agent & Marine Recon Landing and Support
D. Mining- Done as a second priority to torpedo attacks
E. Photo Reconnaissance- After September ’43, Every Landing was preceded by a Submarine Photo Recon.
F. Support of Amphibious Operations
G. Lifeguard Duty–Later in War when targets were few and far between, to rescue downed aviators in forward areas (as with George H. W. Bush)

Captain John F. O’Connell USN (Ret.) has published two books on “Submarine Operational Effectiveness” (I Universe Bloomington Indiana) Part I goes up to 1939 and Part II is for World War II period.

In his 260 pages of text in Part II he uses about 45 pages to describe US Submarine Operations in the Pacific. That’s the shortest summary I can think of.

I hope this helps.

Jim Hay
Capt. USN (Ret.)

Dear Captain Hay,

Thank you so much for these references, actually I am familiar with Roscoe. As for your list of missions, we had a bright young submarine officer going to SAMS and he did a wonderful monograph on submarine support to land operations. Finally, as I read all the emails I realized that I might have a short-term solution three feet away from my keyboard- Fleet Admiral King’s Official Reports to the SECNA V published in 1946- the submarine section is a tight, concise 3 and half pages. I added a quick addendum as you can see to help explain the numbers. I added my former submarine officer brother to the cc line (pre-com USS LOUISVILLE), I hope you do not mind. Sorry for the size of the attachments.

Very Respectfully, John

John T. Kuehn, Ph.D.
Associate Professor of Military History
U.S. Army Command and General Staff College
Fort Leavenworth, KS


Washington United States Navy Department 1946

(Ed. Note: Addendum to Professor Kuehn ‘s letter to the Editor)

Submarine Operations

Submarine warfare was an important factor in the defeat of the Japanese. With the end of hostilities, it is now possible to reveal in greater detail the splendid accomplishments of the submarines of the Pacific Fleet and the Seventh Fleet. Our submarines are credited with almost two thirds of the total tonnage of Japanese merchant marine losses, or a greater part than all other forces, surface and air, Army and Navy combined. (See Plate 18.) Of the total number of Japanese naval vessels sunk, our submarines are credited with almost one third.

Attacks on Merchant Shipping

Our submarines, operating thousands of miles from their bases and deep within enemy-controlled waters, began their campaign of attrition on Japanese shipping immediately following the attack on Pearl Harbor, and continued to fight with telling effectiveness until the Japanese capitulated. During the early part of 1942, while our surface forces were still weakened by the Japanese initial attack of 7 December 1941, submarines were virtually the only United States naval forces which could be risked in offensive operations. Although the number of submarines available at the start was so small that the 1500-ton fleet-type class was augmented by older types, submarine attacks produced immediate and damaging results, which were greatly needed at the time. They made it more difficult for the enemy to consolidate his forward positions, to reinforce his threatened areas, and to pile up in Japan an adequate reserve of fuel oil, rubber, and other loot from his newly conquered territory. Their operations thus hastened our ultimate victory and resulted in the saving of American lives.

Sinking of enemy merchant ships rose from 134 ships totaling 580,390 tons in 1942 to 284 ships totaling 1,341,968 tons in 1943. Then in 1944, when submarine coordinated attack groups reached the peak of their effectiveness, the merchant fleet of Japan suffered its worst and most crippling blow-492 ships of 2,387,780 tons were sunk or destroyed in submarine torpedo and gun attacks. The figures given above, which are based on evaluated estimates, include only ships of 1000 tons and larger. It should be borne in mind that our submarines sank or destroyed, chiefly by gunfire, large numbers of small vessels, particularly during the latter part of the war, when few large enemy ships still remained afloat.

In 1945, because of the tremendous attrition on Japanese shipping by our earlier submarine operations and the destructive sweeps by our fleets and carrier air forces, enemy merchantmen sunk by submarines dropped to 132 ships totaling 469,872 tons. The advance of our forces had further driven Japanese ships back to the coast lines and shallow waters of Japan and the Asiatic mainland. Our submarines followed the enemy shipping into these dangerous waters and made many skillful and daring attacks, such as the one in April when TIRANTE entered a patrolled anchorage in Quelpart Island to blow up a 10,000 ton tanker and two 1,500 ton escort vessels, which were peacefully lying at anchor. Further south, persistent submarine patrolling plus air sweeps had, by the end of March, stopped almost all enemy traffic along the sea lanes of the East Indies and the coast of Indo-China.

For a time, Japanese shipping continued to ply in the East China and Yellow Seas, but the invasion of Okinawa in April soon made the East China Sea untenable to the Japanese. Causing heavy damage, our submarines were very active during April and May in the Yellow Sea and along the east and south coasts of the main Japanese islands. In June the landlocked Sea of Japan was penetrated in force. The submarines had excellent hunting, and in a series of coordinated attacks did tremendous damage to the remnants of the Japanese merchant fleet. One of the intruders, BARB, even landed a party on the coast of Honshu, and successfully blew up a bridge and the speeding train that was crossing it. By the end of the war, the Japanese merchant fleet was virtually nonexistent.

Attacks on Naval Vessels

While United States submarines were effectively eliminating the Japanese merchant fleet, they were also carrying out damaging attacks on Japanese naval units. During the course of the war, the following principal Japanese combatant types were sent to the bottom as a result of these attacks:


Battleship 1
Carriers 4
Escort carriers 4
Heavy cruisers 3
Light cruisers 9
Destroyers 43
Submarines Minor combatant vessels and naval 23
auxiliaries (including 60 escort vessels) 189

Details of these sinking’s will be found in Appendix A. While the loss of the heavier naval units was critical to the Japanese, especially as the strength of our surface fleet increased, the surprisingly high losses of enemy destroyers and escort vessels to submarine attack are particularly noteworthy. Our submarines, refusing to accept the role of the hunted, even after their presence was known, frequently attacked their arch-enemies under circumstances of such great risk that the failure of their attack on the enemy antisubmarine vessel placed the submarine in extreme danger of loss. So successful, however, were these attacks that the Japanese developed a dangerous deficiency of destroyer screening units in their naval task forces, and their merchant shipping was often inadequately escorted.

Special Missions

Among the special missions performed by submarines were reconnaissance, rescue, supply and lifeguard duties. An outstanding result of effective submarine reconnaissance was the vital advance information furnished our surf ace and air forces prior to the Battle for Leyte Gulf, information which contributed materially to that victory. Our submarines in a number of instances rescued stranded personnel and performed personnel evacuation duties notably from Corregidor. The supplies and equipment delivered by submarines to friendly guerilla forces in the Philippines did much to keep alive the spirit of resistance in those islands.

When our air forces came into positions from which they could intensify their attacks on Japanese-held territory, United States submarines were called upon to carry out lifeguard operations to rescue aviators forced down at sea in enemy waters. Sometimes assisted by friendly aircraft, which provided fighter cover and assisted in locating survivors, and sometimes operating alone, our submarines rescued more than 500 aviators during the course of the war.

Fifty-two United States submarines were lost from all causes during the war, forty-six due to enemy action, six due to accidents and stranding. These losses were due to continued penetration deep within the enemy zone of defense, far from our bases, and, until the last phase of the war, far beyond the areas where our surface ships and aircraft could operate. Because of the nature of submarine operations and the general necessity of submarines operating alone, the personnel loss in most instances was the entire ship’s company. As heavy as were the losses in submarine personnel and equipment, submarine training and building programs supplied replacements so effectively that our Submarine Force at the end of the war far exceeded its pre-Pearl Harbor strength- and was the most powerful and effective in the world. The Japanese capitulation found our submarines on station searching for the remnants of the Japanese Navy and merchant marine, and on the alert to rescue downed aviators off the coast of Japan.

Submarines of the Pacific Fleet have been commanded by Vice Admiral C. A. Lockwood, Jr., since February 1943. Rear Admiral James Fife, Jr., has commanded the Seventh Fleet submarines, including a number of British and Dutch submarines, since December 1944.

No account of submarine warfare in the Pacific would be complete without mention of the splendid contribution of the submarines of our Allies. These craft, operating in the southwest Pacific, contributed materially to the destruction of Japanese naval and merchant shipping, and inflicted losses over and above those previously listed.

Addendum to U.S. Navy At War: 1941-1945. by Fleet Admiral Ernest J. King

John T. Kuehn (01/18/2011)

Admiral King’s reports to the Secretary of the Navy James Forrestal offer little explanation as to why the U.S. Submarine Force did so much damage to the Imperial Japanese Navy and the Japanese Merchant Marine during the war beyond the excellence and ferocity of the elite crews and captains of the Pacific Submarine Force. As with most things in history, there is more to the story than American courage and know how. Contingency, serendipity, and accidents played their roles. The numbers cited in the King report, especially the vast increase in tonnages sunk in both 1943 and 1944, require additional discussion.

In the first place, the Americans designed the best long range submarine of any of the naval combatants used in the war, including the Germans, typified by the Tambor/Gato class. These submarine designs were the result of a painful process during the interwar period, but the payoff was extremely high. TAMBOR and later classes had first-of their kind/state-of-the art air conditioning systems, extremely long range, reliable engines and batteries, and were the most habitable submarines of any combatant in the war due to the restrictions of the Washington Naval Treaty and the requirements of War Plan Orange. The Tambor and Gato classes additionally had ten torpedo tubes mounted both fore and aft (six bow and four stem) as well as the ability to mount a five inch deck gun to replace the small three inch gun if required, more on this in a moment.

However, the American Navy went to war with one of the worst torpedo designs of any of the major naval powers- for its submarines, destroyers and airplanes. Because of this deficiency, the initial submarine offensive was a flop. Because of the obstinacy of the senior naval leadership, both in Pearl Harbor and especially at the Bureau of Ordinance, which had overseen the Mark XIV torpedo program’s testing, development, and operational employment, the torpedo problem was not fixed until mid-1943. The increase in numbers of sunk merchant tonnage in 1943 reflect this fix and then the additional tonnages in 1944 reflect an entire year of these excellent submarines with a now serviceable torpedo at work.

However, there is more to the story. The normally catastrophic torpedo situation eventually worked in the U.S. Submarine Force’s favor. When the torpedoes failed and the first submarine patrols returned with disappointing results, this, plus the cautious pre-war tactical training of the U.S. submarine skippers (commanding officers) often resulted in that officer’s relief. It has been said that fully a third of the Submarine Force’s skippers were relieved in the first year for poor performance that was the result of a combination of bad torpedoes and timid interwar operational doctrine designed for major fleet engagements and not for illegal unrestricted submarine warfare. These officers were often replaced with a new breed of up-and-coming, aggressive naval officers as reflected in reality by Dudley Mush Morton of USS WAHO fame and even infamy. Additionally, U.S. submarines were refitted with the five inch gun mentioned previously in order to allow them to attack targets on the surface when the torpedoes didn’t work or simply after the supply had been expended.

At the strategic level the U.S. had abandoned nearly 160 years of defending the rights of neutral shipping at sea when the Chief of Naval Operations, on the day of Pearl Harbor, issued a terse:


Recently Joel Holwitt has shown that this decision to execute unrestricted submarine warfare did not arise from spur of the moment anger at Pearl Harbor so much as it was the result of deliberate strategic planning in the late 1930’s by the Navy’s senior leadership. The problem was, of course, that this strategy could not be operationalized or even reflected in tactical doctrine and so resulted in the over cautious sub skippers mentioned above. This interacted with Japanese plans with favorable results.

Japan’s merchant marine fleet constituted the great Achilles heel for her maritime empire. The ineffectiveness of the U.S. submarine campaign during the first 18 months of the war reinforced a false sense of security in the Japanese Navy as well as contributed to an ongoing Japanese failure to adequately address anti-submarine warfare (ASW) in its training and doctrine. In fact, there was only one Japanese officer on the Naval General Staff primarily tasked with oversight of ASW. Japanese officers and sailors disesteemed protection of merchant ships as a lesser and even dishonorable naval mission.

The final nail in the coffin that constituted Japan’s vulnerable sea lines of communication had to do with leadership. Admiral Charles Lockwood, one of the pre-war advocates of the Tambor class boats, received orders to take over submarine operations out of Freemantle, Australia in 1942 and his aggressive leadership resulted in Admiral Nimitz bringing him back to Pearl Harbor to command the entire Pacific submarine force (SUBPAC) in early 1943 after the untimely death of Admiral Thomas English. Lockwood was a veritable American version of Karl Doenitz in his leadership of his command. He employed an operational analytical approach in utilizing America’s huge intelligence windfalls from code-breaking and was instrumental in fixing the torpedo problem. The combination of all these factors: Japanese complacency and ignorance of the danger, effective torpedoes, aggressive skippers, intelligence superiority (in tracking ships and convoys), and a superb leader with a highly effective tracking and command and control center in Pearl Harbor hit the Japanese merchant fleet like an underwater tidal wave. The Japanese lost the rest of their merchant fleet in about nine months, especially the precious oil tankers and escorting destroyers (the two top targets in the first part of the campaign). By the time they realized the danger it was too late. This discussion helps clarify the startling numbers in King’s report with one final comment- a third of the Japanese Navy’s warships were sunk by submarines, too .

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