BATTLE BENEATH THE WAVES
WWII U.S. Submarines at War in the Pacific
A history of the U.S. Silent
Service in World War II and
unrestricted submarine warfare against Japan 1941 - 1945
THE PACIFIC SUBMARINE WAR
The island hopping war
waged against Japan posed terrific challenges for the United States armed services during
World War II. Committed to a war in two theaters of operations, the logistics of
moving man and machinery over vast expanses of the Pacific Ocean against
a seasoned and tenacious enemy was an obstacle that certainly had to be
overcome if the war against Japan was to prove to be victorious. Many of
these same issues held true for the Japanese, only to a much
greater degree. Highly dependent on imports, this island nation's
lifeline was the sea.
During
the 1930's many believed that a war in the Pacific was inevitable.
Serious concerns over aggressive Japanese imperialism led to the
imposition by the
United States of potentially debilitating sanctions of raw materials.
With the armed conflict raging in Europe, the isolationist American
leadership sought to avert committing itself to open hostilities, although
clandestine material support of America's European allies was actively in
progress. Negotiations between the United States and Japan had been
ongoing for months. Japan obviously wanted an end to U.S. economic
sanctions. The Americans demanded that Japan pull out of China and
Southeast Asia and for
her to repudiate the Tripartite "Axis" Pact with Germany and Italy before
those
sanctions could be lifted. Neither side was willing to budge. President
Roosevelt and Secretary of State Cordell Hull were anticipating a Japanese
military strike as retaliation - they just didn't know where. The
Philippines, Wake Island, and Midway Island were all very strong
possibilities. American intelligence reports had sighted the Japanese
fleet movement out from Formosa (now Taiwan), apparently headed for
Indochina. The U.S. State Department demanded from Japanese envoys
explanations for the fleet movement across the South China Sea but they
claimed ignorance. U.S. military intelligence reassured the president
that, despite understandable fears, Japan was most likely headed for
Thailand and not the United States.
Unfortunately, the predictions of an armed conflict were about to become a
reality on 7 December, 1941 when the surprise attack by Japanese forces
against the United States Naval base at Pearl Harbor, Hawaii proved to be a
decisively overwhelming success for the enemy. The bottom line was that
the nation of Japan ultimately went to
war when the imports of her vital resources were threatened. Severely
overpopulated, their goal was to assure that this supply of goods and raw
materials would continue undisturbed.
The
Japanese attack on Pearl Harbor was a bold, calculated attempt to gain the
military advantage against the nation that was at the root of her economic
and industrial concerns.
Knowing that the United States was rich in resources and capable of a
considerable military might, Japan's initial effort to secure the
dominating control over the Pacific was unleashed on that "day that will
live in infamy". Their plan being that a decisive, crippling blow to
the Pacific fleet would destroy the United States' morale and her
willingness to fight. Believing that the American masses were committed to
a political philosophy of isolationism, Japan would soon discover that
this was an extremely serious miscalculation of the American fighting
spirit.
In a
matter of a little more then two hours, the Imperial Japanese Navy
inflicted a potent, punishing blow to the U.S. Pacific fleet anchored at
Pearl Harbor, with more than 2400 naval personnel killed and over 700 wounded. All
but the battleship Pennsylvania either lost or out of commission for more
then a year. Two thirds of the US Army Air Force aircraft were destroyed along with
196 navy/marine corps fighter planes. In short, the Pacific U.S. surface
fleet was decimated. Ironically, the Japanese planes barely even buzzed
the American submarine base. The adjacent fuel depot and ammunition dumps
emerged unscathed from the attack; possibly nothing more than an oversight
at the time but an error which would eventually be proven to have been a
grievous military blunder.
The
escalation of tensions during the latter part of the 1930's indicating the
possibility of a
war in the Pacific led the US Navy to actively develop a submarine capable
of supporting surface fleet operations. The desired "fleet boat" would be required
to possess the speed, the range and the ability to maintain extended
deployments which would be necessary for a war in the world's largest
ocean. Various classes of submarines were designed and commissioned but
regardless of the many technological improvements made to the American
submarines, the U.S. Navy's submarine force was caught woefully unprepared for the type of
warfare which they were about to face. All of
the pre-war, peacetime training for the U.S. submarine commanders which was
previously geared in support of the surface fleet, was now obsolete and
impractical. Submarines were originally looked upon to serve as scouts and
screens for the navy's capital warships. Unfortunately, following the
devastating
attack on Pearl Harbor virtually no surface fleet of any consequence
remained in the Pacific waters for which to scout or screen. The
United States Navy developers of tactical planning for submarine warfare
never anticipated the situation that they found themselves in during
those early days of the war. With the American Navy in the Pacific all but destroyed,
the rules of submarine warfare had to be drastically changed.
UNRESTRICTED WARFARE
On December 7th, 1941
there were twenty one submarines attached to the U.S. Pacific Fleet based
in Pearl Harbor: six V class, three of the P class and twelve T class subs
although only eleven boats could actually be considered available for
combat operations. Four were in Pearl Harbor at 7:55 am when the Japanese
began the attack. The USS Narwhal, Dolphin, and Tautog were tied up at the
sub base finger piers while the USS Cachalot was in the navy yard for
repairs. As the first bombs began to fall on Ford Island Naval Air
Station, the crews of the moored subs sprang to action and began firing on
the Japanese torpedo bombers tracing their way to Battleship row (The USS
Tautog is credited with downing a Japanese Kate bomber). By 10 o'clock,
the attack was over. The submarine base survived undamaged, although a
crewman was wounded during a strafing run. Following the attack, the
American submarine fleet received at 4:00pm on the afternoon of 7 December
1941 orders issued by Admiral Harold Stark, the Chief of Naval Operations,
for all available boats to immediately put to sea and for those already
underway to conduct "unrestricted submarine warfare" against anything
Japanese. The primary task of of the United States fleet was to
attack heavy ships (defined as a battleship, aircraft carrier, cruiser
etc). It is important to note the gravity of this very powerful decree.
The United States, by calling for unrestricted submarine warfare,
officially renounced article 22 of the London Naval Treaty of 1930 which
formally spelled out the guidelines and procedures that a submarine was
required to follow when attacking an enemy non combatant vessel. The
London agreement of course permitted aggressive operations against an
enemy warship, however it demanded that the attacking submarine inform a
merchant vessel of the its' intention to sink it; allowing passengers and
crew the opportunity to abandon ship prior to any hostile action. While
this was certainly a gentlemanly way to wage war, militarily it was
largely unfeasible and extremely dangerous for the submarine. To be in
compliance with the agreement, the submarine would have to leave the
relative safety of the ocean's depths by surfacing, rendering her highly
vulnerable to an air attack or a counterattack by the an enemy warship.
The U.S. rationalization for dismissing the London Treaty was that Japan's
attack on Pearl Harbor constituted a serious breach of international law.
Further the U.S. anticipated that Japan would arm and escort her merchant
fleet. Finally, owing to the fact that all Japanese marus (merchant ships)
would fall under the direct control of Japan's military, the United States
would be absolved from observing treaty restrictions and any offensive
operation against a merchant vessel was justified as enemy merchant ships
were no longer "non combatants". With the attack on Pearl Harbor and
the CNO's call for unrestricted warfare, U.S. submarine commanders now had
free reign and the blessing of the Naval High Command to seek out and
attack any ship flying the flag of the Rising Sun.
Previously during peacetime, strict adherence to the London Treaty of 1930 was
understood and absolute. As a result combat training concentrated solely
on offensive operations against the swifter warships and not against the slower,
lumbering merchant vessels which they were now permitted to target and engage. Untrained
for waging this type of search and destroy mission, it is small wonder
that the submarine commanders recorded poor initial tallies. Much can be
attributed to the fact that caution seemed to be the watchword for the
submarine fleet. Tactical peacetime doctrine demanded that attacks against enemy vessels
were to be made from deep submergence and well below periscope depth using only sonar bearings in which to develop an acceptable firing
solution. Surface attacks, which proved to be such an important tactic of
the German U-Boats in the Battle of the Atlantic, were out of the
question for U.S. submarines. In addition, it was discovered that from the air a submarine
could be detected to depths of over one hundred feet during conditions of
optimal visibility so all submarines were required by orders to remain
submerged within 500 miles of an enemy airfield. This only tended to
reinforce the belief that operational caution was critical, thus
compounding the poor performance of American subs early in the war. Few skippers were willing to buck the pre-war rule book by
coming to surface or periscope depth for an attack. All were career
officers, generally older and thus much more conservative and cautious in
combat. Consequently, most of the early offensive maneuvers were made from
the safety of deep water by sonar, with predictably dismal results. The lack of
offensive initiative and flawed doctrine however were just a part of the
problem. Defective torpedoes was an issue that would severely reduce
the submarine fleet's effectiveness during the first few years of the war.
Additionally, the lack of a unified submarine command compounded the
challenges. Infighting between the Pacific Fleet based in Pearl and the
Asiatic Fleet in Manila for manpower and materials accounted for a schism
in command that lasted throughout virtually the entire war.
Fortunately, major intelligence advances were being made at this time by
the United States in intercepting and deciphering Japanese communications.
The three cryptanalysis units, Cast (Cavite, Manila Bay), Hypo (Hawaii)
and Negat (Navy H.Q., Washington) were highly successful in breaking the
latest Japanese code. Luckily, the Japanese were a talkative bunch, and
messages concerning their movements, strategies and plans were frequently
broadcast over their military airwaves. Possessing the ability to decipher
the communications, the US codebreakers would forward this critical
information to submarine captains in the form of the famous "Ultra". This
top secret skill was so closely guarded that one submarine division
commander chose to stay with his sinking boat when his sub broached after
getting depth charged and being hammered on the surface by gunfire from an
IJN destroyer. Choosing to remain on board the sinking USS Sculpin,
Captain
John P. Cromwell was posthumously
awarded the Medal of Honor for his actions in avoiding capture with the
possibility of being subjected to torture and giving up the secrets about
Ultra and naval operations in the Pacific. But even with the "heads up" intelligence information being
provided, tactical positioning errors by top leadership continued to haunt
the submarine fleet. Boats were continually given orders of deployment to
stalk the entrances of harbors and ports, ignoring the fact that the bulk
of the Japanese shipping was concentrated along established, high seas
trade routes. The decision to retire the S-Class boats from active combat
duty resulted in the reassignment of seven fleet boats from the Asiatic
Fleet to the Solomons for picket duty. With fifteen boats based in western
Australia, this move had essentially cut the Asiatic Fleet's complement in
half, leaving fewer submarines available to actively hunt for Japanese
merchant and military shipping.
When the
war began, U.S. submarines had no RADAR (Radio and Detection Ranging) but
by August of 1942 an air search system (the SD) and the first surface search RADAR system
(the SJ) was installed aboard a US
submarine. The SJ RADAR although it still was unfortunately full of kinks, was a
tremendous boost to navigation and surface vessel detection and location.
In addition, the new Gato class boats were arriving on a regular basis to
replace and reinforce those battle weary subs which had been bearing the
brunt of the war so far. While armed with an established set of patrol and
attack guidelines at the war's outset, boat commanders were finding that
they were actually in a "learn as you go" situation. As a result new
tactical procedures were being developed, often times much to the
displeasure of their superiors. For once however, things began to look
favorably for the US sub fleet. At least for a brief period. Torpedo
failures were numerous and succeeded in handcuffing many skippers. BuOrd
(Bureau of Ordnance) held steadfast to the opinion that human error was
the the cause of the torpedo troubles, and not a design flaw. Compounding
the sub fleet's problems, poor tactical positioning on the part of the top
Navy brass continued with a seeming vengeance. The Pacific submarine
forces were often split up, and the deployment of boats out of high
contact areas to patrol zones that were considerably poorer in
productivity occurred frequently.
By early
1943, the US had begun limited use of a proven cooperative attack tactic
known as "wolf-packing". An important part of Germany's U-boat success in
the Atlantic, the US wolfpacks returned mixed results. Confidence in the
ability of two or three fleet boats to execute a cooperative attack
against any enemy vessel ran high, but the dedication of these subs to a
single attack was considered by some to be a poor use of military assets.
Japanese convoys operated with a far fewer number of ships then did those
merchants transiting the Atlantic and getting thinned out by the extremely
efficient U-Boat wolfpacks. there were considerable difference in the High
Command of U.S. and German submarines. Admiral Karl Dφenitz, the commander
of the U-Boat arm of the German Kreigsmarine, virtually micro-managed his
boats movements and maintained almost continual radio contact with his
boats, directing many of the operations.
TORPEDO TROUBLES
Torpedo
problems plagued the fleet submarine throughout much of the war, but
the early years proved to be the most trying time for sub skippers
regarding the ordnance they carried. Malfunctioning torpedoes were
reported by boat captains from the onset of hostilities and the response
from BuOrd was always the same: The weapons were fine, it was the crew's
inabilities that were to blame. History has proven otherwise.
US fleet
submarines went into battle armed with the MK XIV steam torpedoes which
were equipped with the MK VI influence exploder. The design behind the
exploder was to allow the torpedo to detonate within the magnetic field
under the keel of the target boat, effectively breaking the ship's back. This "top secret" device was highly regarded by the Navy which believed
they possessed a device that
would revolutionize submarine warfare. In fact, they so tightly guarded
the information about the MK VI that they conducted few actual tests. In
addition, training in its' use was restricted for fear that the secret
about this lethal miracle might leak out. During the same time the US was
tenaciously safeguarding the MK VI, both Britain and Germany abandoned
their use of a similar devices they had developed due to the equipment's
unreliability. Skippers complained that, after developing an ideal attack
setup, their torpedoes would detonate prematurely, miss completely or not
explode at all. In December of 1941, after having fired in excess of 70
torpedoes at 28 targets only one hit was recorded. Theories as to the
cause were widespread. The most popular being that the weapons were
running deeper then they were set. Report after report of potentially
faulty torpedoes came down the pike, only to be officially attributed as
"crew error". Resolution to the problem took its first step forward when
in June of 1942 RADM Charles Lockwood, a submarine
veteran, was assigned the command of the Asiatic Fleet. His first order of
business was to test the MK XIV for running depth. His findings were
consistent with the reports from the submarine commanders: the MK XIV ran
deeper then their settings. The skippers were advised to adjust the
running depth accordingly in the hopes of correcting the defect.
Unfortunately, the number of sinkings and total tonnage scores remained
disturbingly lower then expected. Continuing on the belief that the poor
showing was due to ineffective skippers, many were relieved of their
commands, replaced by younger, more aggressive officers.
If the
possibility of conducting a war patrol armed with faulty torpedoes was not
a huge enough problem, the shortage of their supply, defective or
otherwise, was. Political arms limitation agreements prior to the war
restricted the ability of countries to produce certain weapons. Even with
the advent of antisubmarine technology, submarines themselves were
considered to be an extremely deadly weapon of war, and there was a
worldwide effort to restrict their production. Rules of engagement even
set boundaries as to how a submarine could be employed. The United States
entered WW II with an inadequate supply of torpedoes and too few
facilities to produce the numbers required. The resulting shortage
severely handcuffed skippers during a patrol. By November of 1942, Pearl
Harbor's supply had dwindled down to zero. The Navy issued guidelines
detailing the number or torpedoes that could be expended on any one
target. As a result, many potential targets escaped.
By 1943,
with the submarine fleet still unable to prove their overall
effectiveness, boat captains were once again casting the blame for their
troubles on faulty ordnance. Patrols returned to base with tales of
torpedoes which would explode about half of the time. Finally convinced
that the MK VI influence exploder was the culprit, Lockwood ordered them
to be disconnected. But the saga of defective weapons continued. As
numerous patrol reports continued to describe perfect set ups followed by
torpedoes striking the targets but failing to explode, (one account
detailed an attack where 13 out of 15 hits did not detonate) Lockwood
ordered new tests to be conducted. Firing torpedoes at a vertical cliff
face, the duds were closely examined. It was determined the when a torpedo
struck at a 90Ί degree angle (which was considered ideal) the firing pin
would often become distorted before it could contact the explosive cap.
The results confirmed what many had feared, that submarines went into
battle armed with defective weapons. Installing a stronger firing pin
resolved the issue of malfunctioning torpedoes virtually overnight. The
resulting dramatic increase in tonnage scores removed any doubt as to the
cause of the problem that bedeviled the submarine fleet during the first
few years of WW II.
TURNING POINT
Towards
the end of '43 the situation for the US submarine fleet had begun to
improve considerably. The arrival of newly commissioned boats was
exceeding the total number of losses and the difficulties regarding
malfunctioning torpedoes was in the process of being resolved. As a
result, the submarine
fleet was steadily inflicting severe damage on enemy shipping (by the
close of that year, US submarines had sunk over 1, 500,000 GRT of Japanese
merchants). Moreover, the re-evaluation of patrol zones by RADM Charles
Lockwood resulted in boats being deployed to areas that would allow
for an increased number of contacts. The allied victory during the Battle
of the Philippine Sea dealt a devastating blow the to the Japanese
military machine. Three of five IJN aircraft carriers were sunk (two by
submarines) and the substantial loss of aircraft basically all but
terminated the Japanese Naval air force. A new directive was issued to the
US submarine fleet ordering the targeting of Japanese oil tankers in an
effort to cut of their fuel supplies throughout the Pacific. With US
submarines sinking enemy vessels at a rate of 50 per month in 1944, the
picture looked bleak for Japan. Serious supply shortages were effecting
their ability to continue the war effort . The conflict they initiated
several years prior was looking more and more apparent to end in certain
defeat. However, their determination and resolve never wavered.
Still to come were the battles for Okinawa, Luzon, Formosa and Iwo Jima.
As the Japanese fleet retreated to areas where crude oil was available,
allied forces were able to establish advanced naval bases which reduced
the tremendous transit time from the main sub bases to the patrol zones.
US
codebreakers were picking up messages which proved highly productive on a
regular basis and by the early months of 1945 the hunting grounds of the
US submarine fleet were getting thin. The number of prize targets had
dwindled down to a precious few owing to the devastating impact the silent
service had on merchant and military shipping. The decreasing number of
available targets thus prompted a shift in how American subs were
utilized.
With the knowledge that
Japan's merchant fleet had been seriously and substantially degraded, the
civilian sampans became the ever increasing target of American
submarine searches and attacks. It was reasoned that these small, flat
bottomed fishing vessels could be the alternate, desperate means of
shipping that the Japanese were employing to run supplies. US submarines
would typically surface and board these boats in search of military
contraband; sinking those that were found to be holding ammunition
and other obvious materials of war. Anticipating the invasion of the
Japanese homeland along with the opportunity to break into the Sea of
Japan (which still sheltered enemy shipping) saw submarines employed in
both mine detection and photo recon missions. Not since Mush Morton and
the Wahoo had U.S. submarines attempted to reap the bountiful rewards of
conducting a war patrol in the Sea of Japan. Generally shallow in depth
and safeguarded by heavily mined approaches, this target rich area was
considered too dangerous a place to hunt. The introduction of the FM
sonar, originally developed for mine sweepers, provided the needed
technology to accurately locate and chart the previously impenetrable mine
fields. The end of the war was at hand. Hiroshima and Nagasaki guaranteed
it.
CLOSING COMMENTS
The
overall impact that the United States Navy's submarine forces had on the
outcome of the war in the Pacific is often understated. The
modernization of the world's navies during the WW II era saw an
incredible shift from the dependence upon the battleship towards the
aircraft carrier and its' support groups. The recognition and glory
which has been showered upon this formidable arm of the US Navy is,
without question, certainly warranted and deserved. But to study the
Pacific theater without looking closely at the battle figures compiled
by the Silent Service would be a grave injustice to any student of the
war and to the valiant men who unselfishly gave of themselves.
Comprising less then 1.6% of all US Naval personnel in the Pacific, yet
accounting for more then half of all enemy shipping sunk, the US
submarine fleets were well represented in the Allied effort for
achieving victory. Historians have stated that a major factor
contributing to Japan's surrender was this island nation's recognition
of the fact that she was unable to sustain the war effort due to the
severe shortages of raw materials and basic essentials. By eliminating
their ability to import vital goods and supplies, American submarines
were able to do to Japan what Hitler's U-Boat force came close to doing
to England.
The officers and men of the US Silent Service, having had to re-write
wartime tactical doctrine on the fly, were undoubtedly modern military
pioneers. History has provided a place for these valiant sailors and the
incredible deeds they performed by securing a prominent position in the
expansion of any nation's naval fleet for a powerful submarine force.
The final tallies show that of the 10 million tons of military and
merchant shipping lost by the Japanese during WW II, US submarines
accounted for a total of 54%. The interesting question remains as to how
much earlier could the war have been brought to a close had the US
submarine fleet been initially equipped with reliable torpedoes. The
overall effectiveness of the submarine war and the tremendous
contribution that the men of the silent service made towards its' final outcome is
truly historic.
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