On the twenty-fourth of July 1943, Lieutenant Lawrence Randall Daspit stared through the periscope of the submarine USS Tinosa at the Tonan Maru No. 3, a Japanese tanker of over nineteen thousand tons. His first attack had stopped the ship. Now she lay dead in the water beside him, close enough that a miss seemed almost impossible.
Daspit fired. The torpedo struck. Nothing. He fired again.
Another hit. Nothing. Again and again, Mark 14 torpedoes struck a stationary target and refused to explode. By the end of the attack, Tinosa had fired fifteen torpedoes, and eleven observed hits had failed to detonate.
Daspit kept the sixteenth. He turned back toward Pearl Harbor, not to fight, but to prove that the weapon itself was broken. This is the story of how the American submarine force fought a war with a defective weapon, and what it took to fix it before more men died carrying torpedoes that could not kill. By the summer of 1943, the American submarine force in the Pacific was waging war with a weapon it could not trust.
Patrol after patrol returned to Pearl Harbor with the same report. Torpedoes fired from close range, carefully aimed, running true toward the target, then doing nothing. Commander Dudley Walker Morton, the thirty-six-year-old captain of USS Wahoo and one of the fleet’s most aggressive submarine commanders, had suffered devastating torpedo failures on earlier patrols. His Mark 14s produced only a muffled metallic thud.
Attack after attack, from distances well under a thousand yards, Morton watched torpedoes that should have torn ships apart bounce off them or sink without exploding. The problem was not new. Submarine commanders had reported torpedo failures since the first weeks of the war in December 1941, and the Bureau of Ordnance had spent eighteen months rejecting every complaint with the same explanation. The bureau insisted the fault lay with the men firing the weapons, not the weapons themselves.
Commanders were firing from too far away, their approach angles were wrong, or their crews were not maintaining the torpedoes properly. It was an accusation that enraged the submarine force. These were officers and sailors who had trained for years to hit enemy ships with torpedoes, and they were being called incompetent by engineers and bureaucrats who had never fired a torpedo in combat, never heard the ringing sound of a failed impact against a hull, and never had to explain why another perfect attack had failed. The Mark 14 was supposed to be the most advanced submarine weapon in the world.
It carried a warhead packed with roughly six hundred and sixty-eight pounds of Torpex, an explosive compound with the destructive power of about a thousand pounds of TNT. It could reach forty-six knots thanks to its steam turbine. It was guided by the Torpedo Data Computer, a sophisticated mechanical fire-control system that calculated the intercept course in real time, and it was fitted with the Mark 6 exploder, a dual-purpose fuze that could be activated either by the magnetic field of a steel hull passing overhead or by direct physical contact with the target. On paper, the combination was devastating.
In practice, it had three separate defects, and all three existed at once throughout the first eighteen months of the Pacific war. The torpedo ran deeper than its depth setting indicated, sometimes by as much as ten feet, because the operational warheads were heavier than the practice heads used in pre-war calibration. This meant it passed under the target’s hull without giving either fuze a chance to work. The magnetic component of the Mark 6 was wildly unreliable, exploding prematurely hundreds of yards short of the target or not at all, depending on local magnetic conditions, water temperature, latitude, and factors no one could predict.
And the contact exploder, the simple backup mechanism meant to detonate the warhead when the torpedo physically struck the ship, had a fatal flaw that neither the Bureau of Ordnance nor the fleet had yet discovered. On June 24, 1943, Admiral Chester W. Nimitz, Commander in Chief of the Pacific Fleet, made a decision the Bureau of Ordnance had resisted for more than a year. He ordered the magnetic component of the Mark 6 exploder disabled throughout the Pacific submarine force.
It was a direct override of the bureau’s institutional authority over weapons design and deployment. The order went out from Pacific Fleet headquarters, and across the ocean, from Pearl Harbor to the advanced bases at Midway and beyond, torpedo maintenance crews opened the Mark 14s and disconnected the magnetic influence feature. From that moment on, every Mark 14 fired by an American submarine relied solely on its contact exploder. But disabling the magnetic exploder did not solve the problem.
It removed one layer of failure and exposed the next. With the magnetic feature disabled, the Mark 14 depended entirely on its contact mechanism, the firing pin, guide rods, spring, and detonator caps meant to function on impact. And the contact exploder was failing at a rate that defied all expectations. Submarines were reporting perfect setups, textbook approach angles, torpedoes running straight and striking their targets dead center at under a thousand yards, then nothing.
The sound of metal hitting metal, then silence. No explosion, no damage, no destruction. The most advanced torpedo in the American arsenal had become an expensive, very fast projectile that might occasionally punch a hole in a merchant ship’s hull through sheer kinetic force, but could not detonate its warhead. On the morning of July 24, 1943, Daspit, a man in his early thirties from Alabama on his second war patrol, brought Tinosa to periscope depth near the Japanese stronghold of Truk and found himself facing the Tonan Maru No.
3, a converted whaling factory ship of 19,262 tons. She was one of the largest merchant ships in Japanese service, a huge tanker carrying fuel oil for the Imperial Navy, and she was sailing unescorted. At 5:55, Daspit began his attack. Two of his first torpedoes exploded.
The giant ship shuddered, slowed, then stopped completely. Smoke rose from her midsection. She began to list. She was hit, dead in the water, unable to go anywhere.
It looked like destruction in progress. All Daspit had to do was fire one or two more torpedoes and she would sink. Daspit closed the distance. The Torpedo Data Computer recalculated the course.
Tinosa took up a perfect firing position, less than a thousand yards from a stationary target that filled the periscope lens from edge to edge. Daspit fired one torpedo directly at the ship’s midsection. It ran true, struck the hull, and did not explode. He adjusted the gyro angle slightly and fired another.
Same result, the sound of a metallic impact and nothing more. He moved to a different angle, set up another approach, and fired again. Nothing. Over the next several hours, Daspit continued to fire Mark 14s with precision until fifteen torpedoes were expended.
He tried every angle the launch geometry allowed. He changed depth settings. His crew checked every torpedo repeatedly before loading it into the tube. Thirteen torpedoes were logged as hitting the tanker, and eleven of them failed to explode.
Daspit made a decision that would change the course of the torpedo crisis. He kept his last torpedo. He did not fire it at the Tonan Maru No. 3, even though the ship was still there, still burning, still a perfect target.
He turned Tinosa around and headed back toward Pearl Harbor because the sixteenth Mark 14 was no longer a weapon. It had become physical evidence. Daspit intended to put it in front of Admiral Charles A. Lockwood Jr.
and demand an explanation as to why the primary weapon of the American submarine force was failing. When Daspit arrived at Pacific Submarine Force headquarters with his patrol report and his single unfired torpedo, the evidence he carried was stronger than any argument Lockwood could muster against the Bureau of Ordnance. Here was a physical torpedo, intact and untouched, that could be opened, inspected, tested, and compared against the bureau’s own specifications. Lockwood, the fifty-three-year-old commander of submarines in the Pacific Fleet, had been wrestling with the torpedo problem through reports, tests, and official correspondence for months.
What Daspit gave him was the cold, undeniable arithmetic of eleven failed hits out of thirteen strikes against a target that could not move, at distances where it was physically impossible to miss. There was no room left for the Bureau of Ordnance to deny. No approach angle to blame, no crew error to cite, no tactical mistake to point to. The torpedo was defective.
And now Lockwood had the physical evidence sitting in a torpedo rack aboard Tinosa at the Pearl Harbor submarine base. Daspit was not alone. By August 1943, Morton had sailed Wahoo into the Sea of Japan, where a string of torpedo failures ruined what should have been a successful patrol. Every attack ended the same way, torpedoes running true toward the target, striking the hull, and failing to explode.
Morton, one of the most aggressive and persistent submarine commanders in the fleet, found himself forced to watch ships he had hit directly sail away undamaged. In some cases, the only damage his torpedoes inflicted came from the kinetic force of several tons of steel striking the hull at forty-six knots, enough to bend plates and loosen seams, but not enough to sink anything. It was like throwing rocks at an enemy warship. Lockwood had spent months writing letters, sending patrol reports, and arguing with the Bureau of Ordnance through every available channel.
His approach had been measured, then firm, then blunt. The Bureau of Ordnance responded each time by defending its product, insisting the Mark 14 was functioning within design specifications and that combat failures were the fault of submarine crews. After the incidents involving Tinosa and Tunny, Lockwood made his own decision. He was tired of waiting on the Bureau of Ordnance.
He decided to find the mechanical flaw in the contact exploder himself, and to fix it with whatever was available at Pearl Harbor, to get effective torpedoes back to his submarines before more of his men died carrying defective weapons into battle. The first person Lockwood called was Captain Charles Bowers Momsen, a forty-seven-year-old officer famous for solving problems with unconventional methods since before the war, when he invented the Momsen Lung, a submarine escape device that had already saved lives. Momsen’s idea was direct, as usual. Stop testing torpedoes on paper.
Stop arguing about theoretical performance. Take a submarine to the small island of Kahoolawe, whose shores featured steep volcanic cliffs dropping straight into deep water. Fire live Mark 14s at the rocky cliff face and recover those that failed to explode. For the first time, they would be able to examine a contact exploder that had gone through a real firing cycle and struck a real target without functioning.
Kahoolawe was a small, uninhabited island in the Hawaiian chain that the Navy used as a bombing training range. Its western shore provided exactly what Momsen needed, vertical basalt cliffs dropping directly into water deep enough for torpedoes to reach their running depth before impact. It was essentially a solid wall that could not maneuver, could not sink, and would either make the torpedo work or prove it did not. On August 31, 1943, USS Muskalonge proceeded to Kahoolawe loaded with Mark 14 torpedoes and a plan the Bureau of Ordnance would consider pure madness.
The concept was simple but dangerous. Fire torpedoes at the rocky cliffs until one struck and did not explode. Then send divers to recover it from the ocean floor at the base of the cliff. This meant handling a warhead packed with nearly seven hundred pounds of live Torpex explosive, fitted with an exploder of unknown condition and questionable reliability after striking solid rock at forty-six knots.
Lockwood privately acknowledged the risks but approved the operation. The first two torpedoes struck the cliff face and exploded normally. The third hit the target, produced the usual muffled impact sound without exploding, and sank to the bottom. Divers went down and brought it to the surface.
When the Pearl Harbor torpedo shop crew opened the warhead and extracted the Mark 6 firing mechanism, they found exactly what Lockwood had feared. The firing pin had reached the detonator caps, but the guide rods meant to keep it straight had bent under the force of impact, slowing the pin and robbing it of the energy needed to set off the caps. The contact exploder was effectively destroyed by the very impact it was designed to withstand. The discovery at Kahoolawe drove the Pearl Harbor torpedo shop into a sustained investigation that produced results within days.
Working with warheads filled with inert material instead of live explosive, Momsen’s team rigged a crane at a drydock base and began dropping the heads from ninety feet onto a steel plate to simulate the impact forces of a vertical torpedo strike. The results were clear and devastating. When a Mark 14 struck a target at a perfect ninety-degree angle, the textbook ideal every submarine captain trained to achieve, the deceleration forces reached approximately five hundred times gravity. At that load, the guide rods bent almost immediately.
The firing pin itself, made of steel and relatively heavy, did not have enough momentum against the weak guide rods and the spring to reach the detonator caps with sufficient force. The firing pin assembly was simply too fragile for the forces involved. The Bureau of Ordnance had designed the Mark 6 exploder under peacetime laboratory conditions and never tested it against a live target at full speed. Prototype tests used low speeds and soft targets, conditions bearing no resemblance to the violence of actual combat impact at forty-six knots against the hard steel plating of a warship or merchant hull.
The implications were stunning. The more accurate the shot, the more likely the torpedo would fail. A perfect ninety-degree hit perpendicular to the target’s hull generated maximum deceleration force, virtually guaranteeing the firing mechanism would be crushed before it could operate. In the drop tests, seventy percent of warheads failed on impact at ninety degrees.
An oblique strike at forty-five degrees, which dispersed impact energy across two planes instead of one, gave the mechanism slightly more time and a better chance of functioning. The submarine force had spent nearly two years trying to fire perfect shots, and the perfect shot was what was breaking their torpedoes. Commanders who occasionally got successful hits were not doing so because of superior skill, but because their shots were slightly imperfect, striking at an angle that allowed the defective mechanism to work. Lockwood hastened to send the technical findings to the Bureau of Ordnance, accompanied by photographs, the recovered hardware, and detailed engineering analysis.
The bureau had resisted fleet complaints throughout the crisis, but by mid-September, its own tests were also producing failed contact exploders. On October 4, the bureau approved Lockwood’s firing pin modifications pending production of a satisfactory exploder. Lockwood did not wait for the official production solution. He went to the Pearl Harbor torpedo shop and asked them to fix the problem with whatever materials they could find at the base.
The solution they developed over the following weeks was simple and ingenious. The original steel firing pin was too heavy and generated significant inertia upon impact, causing it to bind against its guide paths. The torpedo shop manufactured a replacement firing pin from aluminum. The aluminum pin was lighter, meaning it could accelerate faster through the guide paths before they had a chance to bend.
They paired it with a stronger spring that pushed the pin with greater force. This combination addressed the underlying physics of the problem, a lighter pin moving faster under a stronger spring through guide paths that no longer had time to deform before the pin reached the detonator caps. The team worked around the clock testing each modification against the ninety-foot drop test that had become the standard of success or failure. Drop test after drop test confirmed the fix.
Five consecutive warheads dropped from ninety feet onto the drydock floor all exploded successfully. Not one, not three, but five out of five, a result that would have been statistically impossible with the original mechanism. Lockwood briefed Admiral Nimitz, who had been following the experiments closely, and Nimitz gave the green light to begin production immediately. On September 30, 1943, USS Barb departed Pearl Harbor carrying twenty Mark 14 torpedoes fitted with the new aluminum firing pins and strengthened springs, the first operational deployment of a torpedo the Pacific submarine force could genuinely trust.
The solution had been designed, built, and tested entirely at Pearl Harbor without the Bureau of Ordnance’s involvement, using materials found at the base. It was not elegant engineering by peacetime standards. It was a field repair forced by necessity, tested against the only standard that mattered, whether it would work when the torpedo struck the ship. While Lockwood’s engineers raced to fix the contact exploder, the war at sea did not wait.
Every day without an effective torpedo meant more wasted patrols, more targets escaping, more opportunities for the Japanese merchant fleet to keep supplying island garrisons, and the submarine force was about to pay a price no engineering fix could erase. In September 1943, Morton took Wahoo out on what would be her final patrol. This time he carried twenty-four Mark 18 electric torpedoes, the Navy’s new weapon based on a captured German G7e design. The Mark 18 was slower than the Mark 14, less than thirty knots compared to forty-six, but it ran on batteries instead of a steam turbine, which meant it left no bubble trail to alert the target or its escorts.
Morton headed for the Sea of Japan again, accompanied by USS Sawfish, which would operate independently in a different sector of the same waters. It was a dangerous mission. The Sea of Japan is an enclosed body of water with only three narrow exits, all under Japanese control, and any submarine operating inside would be effectively trapped if the enemy detected its presence and moved to close the straits. The Japanese were laying minefields across the shallow passages, and air patrols over the exits posed a constant threat.
Wahoo departed Midway on September 13, 1943, and Morton headed north with the same offensive confidence that had made him famous. Over the following three weeks, Morton proved why he was considered the most lethal submarine commander in the Pacific. As he made his way through the Sea of Japan, he began systematically sniping Japanese ships along the coastal routes between Korea and the main islands. The Mark 18 had its own set of problems.
Its batteries generated hydrogen gas requiring careful ventilation, and its range and reliability were affected by water temperature. But the absence of a visible wake made it nearly impossible for targets to detect the Mark 18, giving Morton an element of surprise he had never fully enjoyed with the bubble-trailing Mark 14. Over ten days, he sank four ships. His largest and most destructive attack came on October 5, when Wahoo fired a torpedo at the 8,100-ton transport Konron Maru.
The ship was carrying a large number of troops and naval personnel. When she went down, 544 of them died. It was one of the deadliest single sinkings by a submarine in the Pacific war up to that point. But Morton’s aggressiveness was also leaving a trail.
The locations of the sinkings could be plotted on a map, drawing a clear line of advance from the Korean coast toward La Perouse Strait, the narrow passage between the Japanese island of Hokkaido and Soviet-controlled Sakhalin, one of only three exits from the Sea of Japan. On October 11, 1943, the Japanese were on alert. Two seaplanes and three antisubmarine vessels were positioned at the eastern entrance to the strait, waiting. At 9:20, one of the aircraft spotted a small oil slick on the surface, the kind produced by lubricating oil leaking from a submarine’s propeller shafts.
In the clear, sunlit water, the pilot then spotted the dark shape of a conning tower just below the surface. Japanese records and later wreck evidence indicate that Wahoo dived after being fired upon, was then tracked by the leaking oil slick, and endured repeated air and surface attacks for several hours. Thick black oil mixed with streams of silver air bubbles rose to the surface, marking the submarine’s position clearly as a target drawn on the water. The aircraft rotated their sorties, returning to rearm while maintaining continuous contact.
The patrol vessels moved in and added depth charges to the barrage. At around 1:30 p. m. , the oil slick marking Wahoo’s position stopped moving, while the Japanese air and surface attacks continued for several more hours.
All seventy-nine men aboard were killed. Wahoo was declared overdue on December 2, 1943, and struck from the Navy’s records on December 6. Back at Pearl Harbor, the news hung over the submarine base like a weight. Morton’s name was on every bulletin board, in every mess hall conversation.
The crew of every submarine that sailed in the following weeks knew that their best had not returned. The loss of Morton and Wahoo was the harshest morale blow the submarine force suffered during the entire Pacific war. Morton had been a legend, the commander who attacked everything he found, who made Wahoo the most famous submarine in the fleet. His former executive officer, Lieutenant Richard O’Kane, thirty-two years old and newly in command of USS Tang, learned that Wahoo was overdue while Tang was still completing fitting-out and training on the West Coast.
O’Kane had served as Morton’s exec, stood with him in the conning tower during Wahoo’s most ferocious attacks, and learned the art of submarine warfare from the man who had pushed it to its limits. Now he was preparing Tang for her first war patrol, carrying everything Morton had taught him into a war that was about to change. At Pearl Harbor, Lockwood was also adapting his tactics. In October 1943, he deployed the first American wolf pack, three submarines operating as a coordinated group instead of lone hunters.
Captain Momsen, the man who had devised the Kahoolawe torpedo test, commanded Cero, Shad, and Grayback, a formation informally known as Momsen’s Wolves. The American approach to wolf packs was deliberately different from the German model that had terrorized the Atlantic. While Admiral Donitz’s submarines operated in large groups of ten or more, coordinating via radio transmissions from a shore headquarters, a system that had been highly effective in 1942 but was now vulnerable to Allied codebreaking, Lockwood’s packs were small and self-contained, just three submarines with the pack commander aboard one of them, coordinating directly at sea via short-range, low-power radio communications that were very difficult for the enemy to intercept or locate. This was their first operational deployment.
Since Pearl Harbor had begun producing the improved contact exploders in September, some of the torpedoes the pack carried contained the redesigned firing mechanisms. The results were the first field evidence that Lockwood’s solution was working. Torpedoes were exploding on contact at rates that would have been inconceivable three months earlier. Where previous patrols reported one dud after another, the wolf pack submarines reported explosions on impact, real damage, and ships sinking.
But the torpedo problem was not the only danger facing American submariners, and the autumn of 1943 proved that with a series of losses that shook the force to its core. Submarines were being sunk by Japanese aircraft, by escort vessels whose antisubmarine tactics were improving month by month, and by the immense cumulative risks of operating in waters the enemy was learning to defend more effectively. On November 19, 1943, USS Sculpin was operating south of Truk, trailing a fast Japanese merchant convoy. She had been tracking the convoy for hours, maneuvering into attack position, when the Japanese convoy commander proved the enemy had begun to learn.
He anticipated the submarine’s likely approach course and positioned the destroyer Yamagumo in an intercept location. Sculpin was detected, and the depth charge barrage that followed was methodical and precise. Charge after charge exploded around the submarine, rupturing pipes, damaging electrical systems, and causing damage severe enough that the submarine could not maintain her depth. Sculpin was forced to surface in the middle of an enemy convoy surrounded by escort vessels.
She surfaced fighting, her crew manning the deck gun and firing at the surrounding destroyers, but the exchange was utterly unequal. A Japanese shell struck the conning tower, killing the officer in charge and wounding several others. The senior surviving officer assessed the damage, realized the submarine could not dive or escape the escorts, and ordered the crew to abandon ship and scuttle her. Aboard Sculpin was Captain John Philip Cromwell, a forty-two-year-old officer who was not part of the regular crew.
Cromwell was commander of a coordinated submarine attack group, and he carried in his head detailed knowledge of covert operations intelligence, submarine strategies and tactics, scheduled fleet movements, and specific attack plans. Cromwell knew that if he were captured, the Japanese would eventually learn what he knew through interrogation, and the consequences for the entire Pacific campaign would be catastrophic. He also knew that Japanese interrogation methods were not merciful. If he left the ship and survived, the Japanese would interrogate him.
They would use every technique available, and eventually they would extract information that constituted Allied strategy across the entire Pacific. In return, his life was a simple variable. Cromwell made his decision. As Sculpin’s crew began to abandon ship, climbing over the rail into oil-covered water while Japanese shells continued to strike the sinking submarine, he stayed aboard.
He went down with Sculpin, taking his secrets with him to the bottom of the Pacific. He was awarded the Medal of Honor posthumously. The citation noted that he possessed secret intelligence information and chose death rather than risk its disclosure upon capture. Yamagumo pulled forty-two of Sculpin’s crew from the water.
One severely wounded sailor was thrown back into the sea. After interrogation at Truk, the remaining forty-one prisoners were divided between the carriers Chuyo and Unyo, twenty-one aboard Chuyo and twenty aboard Unyo. They were now prisoners of war, heading for the Japanese home islands. Their ordeal had only begun.
The twenty-one Sculpin survivors placed aboard Chuyo were held in a compartment below the waterline. Chuyo was a twenty-thousand-ton ship, converted from a passenger liner and now serving as a troop and aircraft transport, shuttling between Truk and Yokosuka. The prisoners received minimal food and water and were left in darkness. The Japanese treatment of submarine prisoners was notoriously harsh.
Submarine crews were regarded with particular contempt by the Imperial Navy, which considered undersea warfare cowardly and dishonorable. Chuyo was not traveling alone. She was part of a convoy including other warships and transports, but the weather was deteriorating rapidly. A massive storm system was forming across the western Pacific, generating waves that would challenge even the largest ships.
By early December, the convoy was plowing through heavy seas and driving rain, weather that reduced visibility to nearly zero and made it almost impossible for lookouts to spot a periscope or torpedo wake. For the prisoners in the compartment, the storm meant being thrown against bulkheads and steel plates with every roll of the ship, unable to brace themselves, unable to see what was happening because the compartment was sealed and dark. What the prisoners aboard Chuyo did not know was that an American submarine was hunting in the same waters. USS Sailfish was on patrol in the western Pacific, and on December 4, 1943, her radar picked up a contact through the storm, a large ship moving at moderate speed, partially obscured by the echoes of huge waves filling the radar screen in the heavy seas.
The submarine’s commander maneuvered into attack position amid seas so rough the submarine could barely hold periscope depth without broaching. Waves were thirty feet or more, and every time Sailfish rose to fire, the ocean tried to push her aside. Shortly after midnight on December 4, Sailfish fired an initial spread of three torpedoes at Chuyo and scored two hits. She launched another attack about six hours later, then a third at approximately 8:42, after which Chuyo capsized and sank within minutes.
The twenty-thousand-ton carrier was never designed to withstand such attacks. Her hull was that of a converted passenger liner, not armored warship plate. Chuyo sank with most of the men aboard, including twenty of the twenty-one Sculpin prisoners in the compartment below the waterline. One Sculpin prisoner survived the sinking and was picked up by Japanese escort vessels.
The other twenty died in the darkness, trapped inside the ship that was supposed to carry them to a prison camp, killed by American torpedoes fired by an American submarine whose crew had no idea their own countrymen were aboard the target. The historical irony was devastating. USS Sailfish had not always borne that name. She had entered service in 1939 as USS Squalus.
On May 23 of that year, during a test dive off the New Hampshire coast, a catastrophic failure of an engine intake valve flooded her engine rooms and sent her to the bottom at a depth of 240 feet. Twenty-six of her crew drowned. The other thirty-three survived in the forward compartments, breathing worsening air in freezing darkness until a rescue operation reached them. USS Sculpin had helped locate Squalus and established the rescue effort, and USS Falcon lowered the McCann rescue chamber, whose crews successfully brought all thirty-three trapped survivors safely to the surface.
Squalus was then raised from the bottom, rebuilt, renamed Sailfish, and returned to service. Now, four years later, Sailfish had fired the torpedoes that killed Sculpin’s men. The submarine that had helped save Sculpin had destroyed her survivors. No novelist would have dared to write this.
While the tragedy of Sculpin and Sailfish unfolded in the western Pacific, Lockwood’s torpedo modification was beginning to prove itself on a broader scale. Submarines leaving Pearl Harbor in November and December 1943 carried Mark 14s fitted with aluminum firing pins and strengthened springs, produced by the Pearl Harbor torpedo shop since September. Reports coming back from patrols now differed. Commanders were reporting explosions on impact, not every time, because the modification was a field fix rather than a factory redesign, but at rates that changed the attack calculations for submarines.
Where a commander previously might fire four torpedoes hoping one would work, he could now fire two with reasonable confidence both would explode. The arithmetic of submarine warfare was changing. For the first time since the war began, the submarine force could plan an attack based on how many torpedoes a target needed, not on how many duds a commander expected to endure before one finally worked. Meanwhile, the submarine force was expanding a role begun in late 1942 that would define its contribution to the last two years of the Pacific war.
Submarine lifeguard missions had started as early as December 1942, when submarines were positioned near Wake Island during a bombing mission with orders to rescue downed pilots. By October 1943, USS Skate was assigned a lifeguard mission off Wake during carrier raids, cruising on the surface in contested waters with her crew scanning the sky for parachutes and the ocean for life rafts. Over several days, the submarine picked up numerous American pilots and aircrew who had been shot down during the raids on Japanese positions, men who would otherwise have drowned in the open ocean or been captured on enemy-held islands. Each rescue required Skate to surface in daylight within range of Japanese coastal batteries, a calculated risk Lockwood considered worthwhile because every pilot rescued was a trained combat aviator returning to the fight.
When Operation Galvanic, the attack on the Gilbert Islands, began in November 1943, submarine lifeguard stations were part of the operational plan. It was a mission that had nothing to do with sinking ships and everything to do with the nature of the war the submarine force had become part of, a coordinated multi-service campaign where submarines served as scouts, rescue teams, weather stations, and commerce raiders all at once. And for the first time, the primary weapon those submarines carried actually worked when it hit its target. By the end of December 1943, the transformation was visible in the numbers and in the hardware arriving at Pearl Harbor.
The contact exploder had been fixed. The magnetic exploder had been disabled months earlier. The depth-keeping problem had been corrected even earlier, after fleet tests proved the combat Mark 14 ran much deeper than its setting, and new calibrations had been issued. For the first time since December 7, 1941, the submarines of the main striking force were sailing with weapons that worked as designed, a torpedo that ran at the correct depth, did not explode prematurely, and detonated when it struck the target.
New Balao-class fleet submarines were arriving from the shipyards at a rate inconceivable in 1942, slightly larger boats, more capable of diving, equipped with the latest gear, each one representing lessons accumulated over two years of combat patrols. SG radar sets were being updated with PPI scopes, display screens that showed the plane’s position with map-like data of the surrounding ocean instead of the raw oscilloscope traces provided by earlier sets, giving commanders a tactical picture of convoys, escorts, and coastlines that was revolutionary in its clarity. Commander Richard O’Kane, Morton’s former executive officer, arrived at Pearl Harbor aboard Tang in early January 1944, ready for his first war patrol. O’Kane carried Morton’s lessons and Morton’s anger.
He had watched Morton attack with defective torpedoes for months, watched the fleet’s best submarine commander forced to throw rocks at the enemy because the weapons would not explode. Now O’Kane had a new submarine, new torpedoes, and hard-won tactical instincts from a man who had learned his craft under the most aggressive commander in the submarine service. He was about to take all of that into waters where his torpedoes would finally match his aggressiveness. The essential question of why nearly two years of war and hundreds of ineffective torpedoes passed before the Navy isolated and fully corrected the Mark 14’s major defects was not simply a story of technical difficulty.
Although the technical challenge was real, three separate defects had been masking each other, and each had to be identified and fixed in sequence before the next became visible. The aluminum firing pin that solved the contact exploder problem had been manufactured within a few weeks by Pearl Harbor submarine base personnel. The magnetic exploder had been disabled by a single order from Nimitz. The depth-keeping problem had been corrected after fleet tests revealed the gap between training and combat performance.
Each of these fixes was straightforward and simple once identified. The delay came from a combination of inadequate pre-war realistic testing, a shortage of torpedoes allocated for combat and test resources, defects that masked one another, and repeated institutional resistance to fleet reports, particularly from the Bureau of Ordnance, which for much of the crisis insisted its weapon was functioning within specifications and that combat failures were the fault of the men firing it. The solution came not from the institution that built the torpedo, but from the men who had to use it. Lockwood, Momsen, Daspit, and the submarine commanders who kept going out on patrols with weapons they knew were defective, because there was a war to be fought and they were the ones who had to fight it.
By December 1943, those men had given the submarine force a weapon that worked. What the force would do with that weapon in 1944, when American submarines sank more Japanese tonnage than in the previous two years combined, would change the course of the Pacific war.
