The American Submarine Campaign in the Pacific Changed the Tides of WWII

The American Submarine Campaign in the Pacific Changed the Tides of WWII

Larry Holzwarth - October 26, 2020

When the United States entered World War I, it cited among its reasons the renewed unrestricted submarine warfare practiced by the Imperial German Navy. So-called cruiser rules of the day required submarines to warn merchant ships before attacking and sinking them. After the British armed merchant vessels, the Germans decided the cruiser rules were impractical and ignored them, attacking ships without warning. Most American and British naval officers, and many of their German counterparts, considered submarine warfare inhumane, dishonorable, and outside the rules of warfare among gentlemen.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
The United States cited unrestricted submarine warfare as a cause fot entering World War I in 1917. Timothy Hughes Rare Newspapers

Times change. On December 7, 1941, just six hours after the bombing of Pearl Harbor, the order went out to the American Pacific and Asiatic fleets to execute unrestricted submarine warfare against all Japanese shipping. Though it did not begin well due to a multitude of problems, American submarines eventually sank 55% of all Japanese ships lost during the war. The total included over 200 Japanese warships, among them two of the aircraft carriers which participated in the Pearl Harbor attack. It required a massive national effort. Here is just part of the story of the American submarine campaign against the Japanese Empire in the Pacific during the Second World War.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
A Japanese maru of the 1930s. Wikipedia

1. The Japanese home islands could not support themselves

Japan’s home islands did not produce the raw materials to support its population, let alone wage war. The Japanese needed a large merchant fleet to transport their needs from their areas of conquest to their population and industries in the home islands. At the time of their attack on Pearl Harbor and their sweep through southeast Asia and the Pacific, the Japanese merchant fleet consisted of nearly 8 million tons of shipping. Japanese military planners estimated a base of over 6 million tons needed to be maintained to support their war effort and feed their people throughout the war. Thus, at the time of the attack, available shipping sufficient for their needs existed.

The Japanese did not bomb the submarine base during the attack on Pearl Harbor, though they did when they attacked the Asiatic Fleet in the Philippines. There, they sunk the submarine USS Sealion. Most of the Asiatic fleet’s submarines withdrew to Australia by the end of January 1942. Submarine war patrols began on December 11, 1941, when USS Gudgeon departed Pearl Harbor for its first patrol. Submarines assumed the role of reducing the size of the Japanese merchant fleet. The commanding officers in the fleet at the time had been trained to enforce the cruiser rules against unrestricted submarine warfare. They out to sea with the orders countermanded.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
A sinking Japanese ship photographed through the periscope of USS Seawolf in 1942. US Navy

2. The submarine campaign started poorly for the Americans

Prior to World War II, American naval planners and strategists did not envision participating in unrestricted submarine warfare. The submarine’s chief role consisted of scouting and reconnaissance for the fleet, and attacking large enemy warships. Consequently, the young officers commanding American submarines at the onset of the war found themselves in a role for which they had not received adequate training. Some bypassed merchant targets, to conserve their torpedoes for what they viewed as larger game, enemy aircraft carriers, cruisers, and battleships.

Many of the boats operating in the Pacific at the start of the war were all but obsolete. In fact, the Asiatic Fleet, which operated independently, contained more modern fleet submarines than available at Pearl Harbor. This caused a gap in areas where submarines operated on patrol. Nonetheless, by March 1, 1942, the Asiatic Fleet’s submarines had accounted for 12 Japanese ships, losing four of its own boats. Its 27 submarines participated in the attempt to thwart the Japanese invasion of the Philippines, unsuccessfully, and withdrew to Fremantle in Australia. As in most aspects of the first three months of the Pacific War, the submarine force failed to blunt the enemy’s thrust.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
Problems with the Mark 14 torpedo plagued submariners for nearly two years. US Navy

3. The Mark 14 torpedo failures crippled American efforts

To call the Mark 14 torpedo problematic during the first year of the war is an understatement. Long before America entered the war, political and contractor controversies arose over its development. Congressmen squabbled over where it would be built, and by whom. Navy input to the debate was overridden by political concerns. By the time the United States entered the war an acute shortage of torpedoes plagued the Navy. Japanese bombing of the Asiatic Fleet’s base at Cavite Bay in the Philippines destroyed a significant portion of that fleet’s inventory. Torpedo shortages exacerbated the submarine commanders’ desire to conserve available weapons, not wanting to waste them on lesser targets.

Another problem existed with the Mark 14’s fired at enemy targets. Skipper after skipper returned from patrols with reports of torpedoes hitting their targets and failing to explode. Others reported premature explosions, and others the rather nasty tendency of the weapon turning back at the submarine which had fired it. The weapon also had a tendency to run at a deeper depth than prescribed. Submariners risked their lives to deliver the weapon on target, only to have it fail. The Navy’s Bureau of Ordnance blamed the submariners. The acute shortage of torpedoes prevented adequate testing of the weapon. Congress demanded a resolution to the problem, for which they shared a large portion of responsibility. Meanwhile, 1942 dragged on, and submarine casualties mounted in the Pacific.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
US Navy torpedo factory at Alexandria, Virginia. Wikimedia

4. Washington bureaucrats blamed torpedo failures on submarine crews

By June, 1942, over 800 torpedoes had been fired by US submarines in combat, with a high percentage failing to explode or exploding prematurely. The number of torpedoes fired exceeded the rate of production of the Navy’s facilities. The submarine force fired more torpedoes than its contractors could supply, and having entered the war already experiencing a shortage, the situation became critical. Worse, submarine commanders reported an increasing amount of torpedo failures during the summer of 1942. In August, after independent testing conducted by Rear Admiral Charles Lockwood confirmed the Mark 14 ran too deep due to design problems, the Bureau of Ordnance agreed.

Once the depth problem was identified and resolved, submarine skippers confirmed an increase in the number of hits on targets, but no sinkings. Most submarine commanders believed the problems came from the Mark 6 magnetic exploder, and petitioned their superiors to remove it. With their request denied by higher-ups, many resorted to removing the exploders after their ships departed for patrol. Once again, the Bureau of Ordnance, Congressional oversight committees, and the Naval bureaucracy spent their time arguing over the issue, while submarine skippers struggled to find the means of gaining reliability over the weapon upon which their lives most depended.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
Admiral Nimitz (left) sided with his submariners in the dispute over the Mark 14 torpedo. US Navy

5. The problematic Mark 14 continued to plague American submarines

The resolution of the depth problem in the Mark 14 revealed the problem with the magnetic exploder, which mainly consisted of premature detonation. From August, 1942 through the early summer of 1943, submarine commanders continued to report what appeared to be hit on target without torpedo detonation. The Bureau of Ordnance sent a technician to examine the problem aboard USS Sargo. His report blamed the problems with the exploders on the submarine’s crew. When Admiral Lockwood heard of the continuing problems with premature explosions, confirmed by intercepts of Japanese reports of attacks, he demanded the magnetic exploders’ removal.

The Commander in Chief, Pacific Fleet, (CINCPAC) Chester Nimitz concurred, and once the magnetic exploders were removed the problem of premature explosions ended. Soon, submarine commanders returned from patrols complaining of hits on enemy ships in which the contact exploder in the torpedoes failed to detonate. Once again, the Bureau of Ordnance claimed the new failure indicated problems with the crews, rather than the weapon. Extensive tests at Pearl Harbor convinced Admiral Lockwood the torpedo, not the crews, remained defective, when 70% of hits at 90 degrees failed to detonate. By September, 1943, the problem had been identified and corrected. After 21 months of underwater combat, the submarine force, at last, had a reliable torpedo, though still in short numbers.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
Admiral Charles A. Lockwood (center, after the war) revitalized the submarine force. US Navy

6. Charles Lockwood reshaped the submarine force

In May, 1942, Rear Admiral Robert English was assigned as Commander, Submarine Forces, Pacific (COMSUBPAC). That same month Rear Admiral Charles Lockwood took command of American submarine forces in the southwest Pacific as COMSUBSOWESPAC. Both officers worked to resolve the numerous problems with the Mark 14 torpedo, with English making several trips to encounter the recalcitrant Bureau of Ordnance in Washington. On January 21, 1943, English died in a plane crash in California, along with several other naval officers. Nimitz requested Lockwood to replace him as COMSUBPAC.

In Lockwood, the submarine commanders and their crews found an advocate for improved weapons, operating conditions, food and supplies, and rest and recreation. Though he never solved the torpedo shortage problem, which continued through the rest of the war, he led the efforts to make the Mark 14 reliable. Lockwood evaluated each submarine skipper in command at the time, reviewing their patrol reports, He replaced those he considered less aggressive than the situation required. He actively recruited young officers to volunteer for submarine duty and training, shaping an officer corps better suited to the improved boats and weapons entering the fleet. He remained in his post of COMSUBPAC for the duration of the war.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
The iconic Royal Hawaiian Hotel became a haven for Naval personnel during World War II. LA Times

7. Lockwood ensured his crews received adequate rest and recreation

In the first two years of the war, submarines departing Pearl Harbor for war patrols were expected to be at sea for 9 weeks or more. Due to their limitations, submarine cruises offered spartan accommodations for the crew. Inadequate storage prevented fresh fruit and vegetables after the first few days. Powdered replaced fresh milk. Unlike surface ships, which often carried ice cream machines, large refrigeration units, and frequently replenished at sea, submariners endured a restricted diet, little personal space, and most canned food. Submariners relaxed with games of cribbage and acey-ducey, watched movies, and worked on qualifications.

Lockwood recognized the need for rest when the crews returned to Pearl Harbor. Submarines arrived at the pier to piles of fresh fruit, crates of vegetables, ice cream, and other amenities long absent. He arranged for returning crews to enjoy stays of two weeks at the Royal Hawaiian Hotel, a Honolulu landmark leased by the Navy during the war. Lockwood frequently stood on the pier as the submarine worked in, ready to greet the officers and crew and discuss their completed patrol. He maintained discipline, but supported the men under his command, especially in conflicts with bureaucrats and others in Washington. He also strictly controlled information released to the press, firmly establishing the submarine force’s reputation as the “Silent Service”.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
Congressman Andrew J. May (left) leaked information which allowed the Japanese to alter their attacks on American submarines. Wikimedia

8. The May Incident endangered American sailors

In early 1943, Kentucky Congressman Andrew J. May participated in a junket to examine the situation in the Pacific Theater. As Chairman of the House Committee on Military Affairs. May had access to classified information. Subsequent events revealed he paid greater attention to lining his pockets through war profiteering than protecting American interests. On his return from the junket, which covered several bases, May held a press conference. During a rosy presentation on the state of the submarine campaign, May informed the press that American submarines frequently evaded Japanese submarines. He also stated the reason. According to May, the Japanese set their charges at too shallow a depth, and he explained American submarines dove deeper than the Japanese thought possible.

May’s comments appeared in numerous newspapers nationally, including in Honolulu, where enraged American naval personnel read them. The Japanese began setting charges to greater depths. Admiral Lockwood wrote the revelation led to the loss of up to ten American submarines in 1943 and 1944. After the war, evidence surfaced that May had accepted bribes from defense contractors, as well as bribes of a personal nature related to draft deferments. He lost his seat in Congress, and eventually went to prison for nine months. He later received a Presidential pardon. According to Lockwood, who never overcame his rage in May, 800 American submariners were lost after the Congressman’s loose lips sank ships.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
USS Robalo launch at Manitowoc, Wisconsin in May, 1943. National Archives

9. Building and testing submarines in Wisconsin required engineering innovations

In 1939 Manitowoc Shipbuilding Company’s President, Charles C. West, proposed a means by which the Wisconsin shipyard could build destroyers for the United States Navy. After completion, the ships would transit the Chicago River, the Sanitary and Ship Canal, the Illinois River, and finally the Mississippi River for delivery to New Orleans. The transit would be in a floating drydock, towed by a tug. After reviewing the proposal the Navy suggested the shipyard build submarines. Though Manitowoc had no experience building submarines (or destroyers) is accepted. The Navy converted Chicago’s Western Avenue bridge to a lift bridge, allowing submarines to transit under tow to the Illinois River.

Once on the Illinois River, the submarines entered the drydock, in which they were towed to New Orleans. Once they arrived there the mast and antennae were installed. Manitowoc received all drawings and design specifications from Electric Boat in Groton, Connecticut, and successfully completed 28 submarines from 1942 to 1945, of two different classes. All of the submarines were completed ahead of schedule and under budget. Most of them were commissioned while in Manitowoc, conducted sea trials on the Great Lakes, and decommissioned for their journey to New Orleans. During World War II it was not unusual to observe American submarines operating on the Great Lakes.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
Submarines detached to rescue downed airmen became known as Lifeguards. US Navy

10. Lifeguard duties became an important role for American submarines

As it became apparent that the major fleet actions of the Pacific War hinged on aerial combat, the need to recover pilots forced to ditch their planes at sea emerged. American industry replaced aircraft in short order. Lost pilots presented another problem. It took many months for the Navy to train replacement pilots, and additional time for them to develop combat experience. Submarines offered a solution for recovering lost pilots. Their stealth allowed them to be pre-positioned before major actions, and radio communications helped them locate and recover aircrew which were forced to bail out or ditch their aircraft, on islands and in the sea.

Rescued airmen typically remained in the submarine once major engagements ended, and the submarine was repurposed as a hunter tasked with finding and sinking crippled enemy ships. The submariners referred to their guests as “zoomies”. Enlisted aircrew messed and slept in the crew’s quarters. Officers were guests in the wardroom. They remained with the sub until it either rendezvoused with a larger surface unit or returned to port. There they found themselves eligible for survivors leave, a temporary respite from combat. During the Pacific War, American submarines rescued over 500 downed airmen, in many instances under direct Japanese fire.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
USS Finback rescued naval aviator and future President George H. W. Bush. US Navy

11. USS Finback rescued a future President of the United States

On September 1, 1944, the submarine USS Finback rescued three downed aviators, a torpedo bomber crew, from the Pacific waters near Iwo Jima. The following day, operating with an escort of two F6F Hellcats, Finback responded to radio messages of a downed pilot north of the island. It took Finback over two hours to reach the site of the reported downed airman, maneuvering on the surface under the protection of the Hellcats. Hoping to locate all of the three men of the crew from the downed torpedo bomber, Finback’s sailors found only the pilot. He identified himself as Lt (j.g.) George Herbert Walker Bush, and reported he had not seen the parachutes of his crew.

Finback searched the area, assisted by Hellcats above, for two hours before it was dispatched to rescue another downed pilot, reported offshore in the range of Japanese guns on Haha Jima. Finback, forced to submerge to avoid Japanese fire, passed near enough to the pilot in a life raft that he could seize the exposed periscope. He held the periscope while the submarine towed the raft away from the island, finally surfacing after Finback had placed five miles between itself and the Japanese guns. The five rescued airmen remained in Finback until September 29, when the submarine arrived at Midway Island. They witnessed Finback sinking two Japanese ships, and endured the retaliatory depth charging with the submarine’s crew.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
USS Trout transferred the wealth of the Philippines to safety in 1942. US Navy

12. Submarines performed rescues of another kind during the war

On February 3, 1942, USS Trout arrived in the Philippines, bearing a cargo of ammunition for the besieged defenders of Corregidor. After offloading its cargo, Trout took aboard 20 tons of gold bars and silver Philippine pesos, listed as ballast on the manifest. It also loaded aboard classified papers from the State Department, securities, mail, and other items too critical to be allowed to be captured by the Japanese. Trout submerged in Manila Bay, waiting out the daylight hours before surfacing at nightfall to take on additional documents and mail. The submarine then began its journey back to Pearl Harbor, carrying with it most of the gold owned by the Philippines.

Despite the value and critical nature of its cargo, Trout did not avoid combat action during the return voyage. Trout engaged at least three ships, sinking two, and narrowly avoided being hit by two torpedoes during actions on the return voyage. The submarine arrived in Pearl Harbor in early March, and transferred the gold, silver, and other cargo to a light cruiser, which conveyed it to safe-keeping in the United States. In addition to other awards, the crew of the Trout received a Distinguished Service Cross from the United States Army for their conduct of the mission. Trout did not survive the war, being lost on its 11th war patrol in early 1944.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
USS Detroit receiving gold from USS Trout, 1942. US Navy

13. Submarines resupplied guerrilla fighters throughout the war

After the fall of the Philippines, bands of Filipino guerillas and American troops who had evaded the Japanese conducted an underground war against the garrison troops. The US Navy dispatched officers to the Japanese-controlled islands to coordinate activities between the various groups, and with US forces. USS Narwhal became the lead submarine supporting the guerrilla operations, though several others participated as well. Narwhal conducted nine highly classified operations in the Philippines, delivering supplies, weapons, American special forces, and transporting Filipino fighters among the islands.

Besides supporting the guerrillas, Narwhal participated in the evacuation of civilians, including women and children, delivering them to safety. Narwhal also transported Japanese prisoners seized by the guerillas, though such were rare since the guerilla fighters seldom took prisoners. By late summer, 1945, Narwhal evacuated prisoners of war freed by the guerillas or simply abandoned by the Japanese. Others were rescued from Japanese troopships sunk by American action. Nearly all of the submarine’s war patrols originated from Australian ports, enabling the submarine to remain on station in the Philippines for extended periods. After the war, Narwhal was broken up for scrap.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
USS Nautilus, one of two submarines to support the Makin Island Raid. National Archives

14. Submarines supported reconnaissance and commando raids

In August, 1942, US intelligence sought information about the strength and disposition of Japanese forces in the Gilbert Islands. They also desired a diversion of Japanese resources from the operations in the Solomons. Accordingly, a raiding force of 211 US Marine Raiders prepared a hit-and-run raid on Makin Island, where a small Japanese garrison was supported by a seaplane detachment. Rather than approaching the island using the surface fleet to land the Marines, two submarines assumed the role of troopships. USS Argonaut and USS Nautilus divided the Marine detachment between them, conveying them to their target on August 17, 1942.

The Marines landed via inflatable rubber boats powered by small outboard engines, though many of the latter failed due to heavy surf. The following night the submarines, which remained outside the lagoon during the raid, evacuated the Marines by the same method. In terms of its main objective – intelligence – the Makin Island Raid failed. It also led the Japanese to reinforce their garrisons in the Gilbert and Marshall Islands. Nine Marines were captured by the Japanese, transported to Kwajalein, and summarily executed. The survivors of the raiding force, which suffered 18 killed in the raid, were sent to Espiritu Santo for recuperation, before their next mission on Guadalcanal.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
USS Tang at Pearl Harbor in 1944. US Navy

15. American submarines faced dangers other than those posed by the Japanese

The problematic Mark 14 torpedo, as well as its successor, the Mark 18, which first appeared in 1943, posed considerable dangers to American crews. Both had a tendency to circle back upon the submarine which launched it, and neither contained safeguards to shut down the torpedo in such an event. At least two American submarines sank as a result of circular runs. In March, 1944, USS Tullibee fired two torpedoes at a Japanese target in the Palau Islands. One torpedo circled back and struck Tullibee. Only one member of the crew, who had been topside at the time of the attack, survived, picked up by a Japanese destroyer.

USS Tang, which became the leading US submarine of the war in terms of enemy tonnage sunk, likewise sank itself with a faulty torpedo. On October 25, 1944, Tang fired its last remaining torpedo at an enemy vessel. Immediately upon firing the circular run became apparent, and evasive maneuvers failed to elude the weapon. Nine men of the 87 aboard survived, including the commanding officer, Richard O’Kane. After enduring beatings at the hands of their captors, the men spent the rest of the war in Japanese prisoner of war camps. Prior to sinking itself, Tang accounted for 33 Japanese ships totaling 116,454 tons. It accomplished that record in just five war patrols.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
USS Dorado, bound for the Panama Canal, sank due to friendly fire. US Navy

16. American submarines were lost to friendly fire when attacked by American ships and aircraft

Friendly fire incidents caused the loss of two American submarines during the Pacific War, the first occurring in the Atlantic. USS Dorado, bound for the Pacific via the Panama Canal, sank after being bombed by a US Navy PBM Mariner operating out of Guantanamo Bay. All hands aboard the submarine died in the sinking. The Navy at first stated the Mariner bombed a German U-boat, and counted the loss of Dorado as an unexplained accident. Post-war examination of German records proved that explanation faulty.

In October, 1944, USS Seawolf, operating off Samar, carried aboard 17 Army personnel as well as its 83 officers and men. A case of mistaken identity led to it being bombed by an American aircraft operating from the USS Midway. The bombs missed, but the airplane dropped a dye marker and notified surface units of the presence of an “enemy” submarine. American destroyer USS Richard M. Rowell attacked with depth charges. The second attack ended with reports of underwater explosions and the appearance of debris. Rowell reported the destruction of an enemy submarine. Seawolf had been in the area to disembark the Army troops to conduct clandestine operations in support of the invasion of the Philippines. The submarine sank with all hands.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
The sinking Japanese Nittsu Maru photographed by its attacker, USS Wahoo, in 1943. US Navy

17. Submarines conducted pre-invasion surveys and reconnaissance

Their covert nature made submarines ideal for scouting the various islands and atolls considered targets as the US Navy drove across the central Pacific. Submarines both landed parties of scouts and surveyors and explored and photographed Japanese defenses and installations. By 1944 submarines conducted coastal surveys of the home islands of Japan. The missions provided data needed by the planners of the invasion of Japan, and the Army Air Force for bombing targets. Submarines scoured the facilities in the Aleutians in 1942 and 1943, preparatory to the American assault to retake Attu. Submarines studied the defenses of Tarawa, Kwajalein, Guam, Saipan, Iwo Jima, Okinawa, and virtually every island invaded in the Pacific.

With rare exceptions, these missions were conducted with the submarines still under their primary orders, which were simply “sink enemy ships” By the end of 1943, Admiral Lockwood had the aggressive commanders he desired in charge of nearly all of the vessels under his command. Submarine bases and tender facilities pushed forward, to Midway Island, eventually to Apra Harbor in Guam, after that island’s recapture. With far shorter voyages to their patrol areas, submarines could remain on the hunt for enemy ships for longer periods. One hunting area remained closed to them, despite the knowledge it was crowded with Japanese shipping. Since the loss of USS Wahoo in October 1943, Lockwood barred his boats from entering the Sea of Japan.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
Another photo from USS Wahoo, showing Japanese facilities in the Caroline Islands in 1943. US Navy

18. Admiral Lockwood pressed to equip his submarines with sonar capable of detecting mines

The loss of USS Wahoo and its commander, Dudley “Mush” Morton, in the Sea of Japan in 1943 hit Admiral Lockwood hard. Morton had achieved legendary status in the submarine fleet for his aggressiveness, poise in battle, and success in sinking Japanese ships. Lockwood wrote of the loss of Morton and Wahoo, “This is the worst blow we’ve had”, adding, “God punish the Japanese”. He believed Wahoo had struck a mine in the Sea of Japan, its last reported position, unable to accept his favorite sub skipper was sunk by Japanese surface or air attack (in fact, a Japanese aerial bomb claimed Wahoo). Lockwood refused to allow his submarines to enter the heavily mined entrances to the Sea of Japan throughout 1944.

During the period he worked with scientists, engineers, and researchers at the University of California Division of War Research to develop sonar capable of detecting underwater mines. Throughout 1944 Lockwood steadily equipped submarines with the new technology, which gradually improved in accuracy, though not to the point they could be risked in combat. Lockwood even petitioned Nimitz to allow him to go on patrol with one of the new sonar-equipped submarines, to further evaluate the equipment. Nimitz considered the idea unthinkable.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
USS Bonefish, lost during Operation Barney in 1945. US Navy

19. Mine detecting sonar made it possible to enter previously closed waters around Japan

The sonar developed throughout 1944 detected small objects, including mines, and notified the operator with a clear blip on a screen, as well as a clearly audible ringing tone. Submariners immediately dubbed the sonar “Hell’s Bells”. The sonar worked on the basis of a frequency modulated (FM) radio signal, rather than an active sonar ping and return. By the end of December 1944, Lockwood’s confidence in the device led him to suggest to Admiral Ernest J. King, Chief of Naval Operations, that it could open the Sea of Japan to submarine incursion. King approved the plan Lockwood proposed, conditionally based on reliability improvements and the endorsement of CINCPAC.

In the spring of 1945, several US submarines equipped with the Hell’s Bells sets began probing the Tsushima Strait, one of the heavily mined entrances to the Sea of Japan. By April, American charts indicated four rows of underwater mines in the straits. In late May and early June, nine American submarines entered the Sea of Japan as part of Operation Barney, all equipped with Hell’s Bells sonar. One, USS Bonefish, sank during the operation, which saw the destruction of 28 Japanese ships, including a submarine and a destroyer. They also sank a Russian ship, leading to a diplomatic incident, since Russia was officially neutral as regarded the Pacific War at the time.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
Late in the war submarines were diverted to rescue downed B-29 aircrews. USAF

20. Not all downed airmen welcomed rescue by American submarines

During Operation Barney, which began in late May 1945, American bombers operated missions over the Japanese Home Islands. Many returned home damaged, and some aircrews often had to either bail out or ditch in the Pacific, awaiting rescue from Navy seaplanes, surface ships, or submarines. On June 1, 1945, one of the submarines participating in Operation Barney, USS Tinosa, received orders to divert from its present course to search for the crew of the B-29 Skyscraper I. The bomber went down in the Pacific about 600 miles from the Japanese coast.

Tinosa located the airmen the following day, afloat in life rafts. Ten survivors went aboard the submarine, received food and water, and then were addressed by the captain. The aviators learned that before returning to their base, they would be operating within the Sea of Japan. The Army Airmen decided to take their chances in the recently vacated life raft rather than endure submarine combat in Japanese home waters. They returned to the raft, with additional provisions from Tinosa, and no doubt heavy ribbing from the submarine’s crew. They were picked up by another submarine, bound for home, and safely returned to their base. Tinosa sank four Japanese ships during Operation Barney, and returned safely to Pearl Harbor on July 4, 1945.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
Wartime films such as 1943’s Destination Tokyo did not convey real conditions in American submarines. IMDb

21. Submarines offered few creature comforts to their crews.

The close quarters in American submarines created the need for innovative storage of supplies. Consequently, the crew slept in bunks in tiers of three, eighteen inches apart. Both forward and aft torpedo rooms carried additional bunks, where sailors slept alongside or suspended above the weapons. The submarines used any available space for stowing food. Beneath the deck, in the cool spaces of the bilges, root vegetables and cabbages kept longer, and added their aromas to the overall smell of the vessel’s interior. Space between machinery and the hull carried canned goods with wooden planks laid above them, allowing technicians access to equipment if necessary.

Showers were rationed, and when a shower was allowed it was strictly regulated for time. Like much of military life, long periods of boredom interlaced with relatively quick intervals of terror. As the war drew on in 1945, targets became scarce. Japan’s merchant fleet had been all but destroyed, and what remained lacked sufficient fuel oil to move. Island garrisons bypassed by the American campaign across the Pacific withered from failure of the Japanese military to resupply them. There remained enough Japanese resistance to create a sense of danger on patrol, but boredom and its effect on morale became a problem for submarine crews by the summer of 1945.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
Periscope photo of the sinking Japanese carrier Unryu, December, 1944. US Navy

22. American code breakers supported the submarine war by identifying enemy ship movements.

In 1942, submarines were dispatched to sea with assigned patrol areas. After reaching their assigned area they conducted operations at the will of the commanding officer, remaining within their designated area. The areas were designated and assigned based on analysis of shipping needs within. That changed in 1943. America’s code breakers, as they had with several other Japanese communication codes, cracked what submariners called the “maru code”. Using the information, intelligence analysts identified Japanese shipping convoys, what they carried, the number of escorts, shipping times, and destinations. The information allowed commanders to route submarines to the areas to intercept the Japanese.

Using the coded information intercepted from the Japanese allowed submarines on patrol to receive updated information while at sea. Japanese convoys at sea provided daily updates of their position, course, and speed, overheard by Americans and relayed to the submarines. Ships sailing individually did likewise, allowing certain targets to be designated as high value to American analysts at Pearl Harbor. The intercepted messages also confirmed Admiral Lockwood’s concerns with the defective Mark 14 torpedo in mid-1943. The Japanese captains informed their commanders of being struck with torpedoes which failed to explode, and American codebreakers intercepted the messages and forwarded them to higher authority.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
US submarines Ulua and Trumpetfish under construction in Philadelphia, summer, 1945. US Navy

23. The submarine service remained a small, elite force throughout the war.

The submarine service, like all branches of the US military during World War II, expanded throughout the war. All volunteers, it remained a close-knit community, with less separation between officers and enlisted men. Nearly all of the men who commanded submarines in the Pacific graduated from the Naval Academy, though reserve officers permeated the wardrooms. In all, just over 50,000 men served in the submarine service during World War II, officers and men included. They represented about 1.5% of the total manpower in the Navy during the war. Only about 16,000 served at sea on war patrols.

The construction of new submarines continued at an increasing pace throughout the war. At the time of the Japanese surrender, 182 submarines were active in the fleet, out of a total of 288 which served during the war. By comparison, at the war’s end well over 6.700 combat vessels comprised the United States Navy. The submarine fleet remained a relatively small element within the overall Naval might of the United States, manned by an elite corps of highly trained and dedicated officers and sailors. After the war, the contribution of the submarines appeared to the public, though it remained unheralded in comparison to the aircraft carriers and surface fleet.

The American Submarine Campaign in the Pacific Changed the Tides of WWII
The submarine force evolved into an elite and exclusive military arm during World War II. Wikimedia

24. Submarines destroyed more than half of all Japanese shipping during the Second World War

The American submarine campaign of World War II crippled the Empire of Japan. During the war, submarines launched attacks against 4,112 merchant ships and tankers. Over 1,000 of those ships sank. In addition, the submarines sank over 200 warships of the Imperial Navy. From the beginning, the secrecy surrounding submarine operations kept much of their contribution from the American public. By war’s end, confirmation using Japanese and American records revealed 4,779,902 tons of Japanese shipping fell prey to American submarines. With the ships went their cargoes. Food, oil, vehicles, raw materials, troops, aircraft, ammunition, and all of the requirements of war were derived of the Japanese by American submarines.

The shortages of materials forced the Japanese to change their war effort, much to their detriment. Fuel shortages forced them to shorten the training for pilots, and American aviators encountered inexperienced opponents in the air later in the war. The lack of fuel, more than anything else, led the Japanese to resort to the desperate kamikaze attacks near the end of the war. Strangulation of the Japanese Empire came at a high price for the American submarine force. During the war, 374 officers and 3,131 enlisted died serving in submarines. The United States Navy honors them as being, “On Eternal Patrol”.


Where do we find this stuff? Here are our sources:

“America’s Undersea War on Shipping”. James M. Scott, US Naval Institute. December, 2014

“War in the Pacific: The First Year”. National Park Service. Online

“Submarine Warfare Played Major Role in World War II Victory”. David Vergun, DOD (Department of Defense) News. March 16, 2020. Online

“US Pacific Submarines in World War II”. William P. Gruner, San Francisco Maritime National Park Association

“Building US Submarines in World War 2”. Captain H. F. D. Davis, Proceedings. July 1946. Online

“Silent Victory”. The US Submarine War Against Japan”. Clay Blair Jr. 2001

“Submarine Activities Connected With Guerilla Operations”. Article, Naval History and Heritage Command. Online

“Operation Barney: Bloody payback in the Pacific”. Steven Trent Smith, Navy Times. September 28, 2019. Online

“Culpable Negligence: A Submarine Commander Tells Why We Almost Lost the Pacific War”. Edward L. Beach, American Heritage Magazine. December, 1980.

“US Navy Non-Combat Submarine Losses and Major Accidents”. Samuel H. Cox, Director, US Naval History and Heritage Command. June, 2018. Online

“Submarines Lost in World War II”. National Submarine Memorial. Online

“How They Won the War in the Pacific: Nimitz and His Admirals”. Edwin Palmer Hoyt. 2011

“Sink ‘Em All”. Charles A. Lockwood, Vice Admiral, USN (retired). 1951