Japanese Couldn’t Believe One U.S. “Destroyer Killer” Sub Sank 5 Ships in Just 4 Days — Shocked The Whole Navy

At 06:47 on June 6th, 1944, the Pacific Ocean was calm, almost deceptively so. The moonlight rippled faintly across the surface as USS Harder cut silently beneath the waves, her steel hull gliding through the black water like a ghost. In the cramped, sweat-soaked conning tower, Commander Samuel Dealey stood hunched over the periscope, eyes fixed on the dark horizon. His knuckles were white where they gripped the handles. The air inside the sub was thick with diesel fumes, machine oil, and the quiet tension that lived in every submarine crewman after weeks of stalking enemies who hunted them in return.

Dealey was thirty-seven, lean, steady-eyed, and built from the kind of discipline that came only from surviving the impossible. He had been at sea for months now, his submarine prowling the waters around the Philippines, attacking Japanese convoys with a precision that had earned Harder a grim nickname among the Imperial Navy — “The Destroyer Killer.” It was a title that made his crew proud and their enemies furious.

Outside, three Japanese destroyers — Minazuki, Hayanami, and Tanikaze — were cutting through the waters off Tawi Tawi at full speed, their searchlights slicing through the mist. They weren’t hunting merchant ships this time. They were hunting him.

The Harder had already destroyed eighteen enemy ships across five patrols. She was fast, aggressive, and commanded by a man who refused to play by the rulebook. For weeks, Dealey had been attacking Japanese convoys around the Sulu Sea with such frequency that Tokyo’s naval command had taken notice. Now, the Imperial Japanese Navy had dispatched its destroyers with one objective — find and sink the American submarine that had turned their shipping lanes into graveyards.

Until that spring, U.S. submarines avoided Japanese destroyers at all costs. A destroyer could reach thirty-five knots. A submerged submarine, barely nine. Between December 1941 and March 1944, fourteen American submarines had been sunk by Japanese destroyers. Not one had successfully sunk a destroyer while both were actively engaged in combat. The odds were considered suicidal.

But on April 13th, Commander Dealey shattered that assumption.

That morning, the destroyer Ikazuchi had spotted Harder’s periscope wake and charged toward it at full speed, intending to ram or depth-charge the sub before it could dive. The usual tactic for submarines in such moments was to crash-dive and flee into deeper water. Instead, Dealey did something that stunned even his own officers — he turned the sub directly toward the oncoming destroyer.

“Flank speed ahead,” he ordered calmly, his voice cutting through the tight space. The crew exchanged uncertain glances but obeyed. The Harder surged forward, closing the gap fast. At nine hundred yards — less than half a mile — Dealey fired four torpedoes in a spread pattern. The men waited in breathless silence. Then came the explosion — two direct hits midship. Ikazuchi’s hull erupted into fire, her boilers bursting, the ship breaking apart in a plume of steam and flame. She sank in five minutes.

Dealey’s report, transmitted hours later, was brief and dry: “Expended four torpedoes. One destroyer.”

The message rippled across the Pacific like an electric current. Among U.S. submariners, Dealey became a legend overnight. Among the Japanese, his name became a curse. Admiral Soemu Toyoda, commander-in-chief of Japan’s Combined Fleet, was not amused. By that point, between January and May 1944, Japan had already lost twenty-three destroyers — far more than they could afford. Destroyers were the backbone of their fleet, essential for both escort and offense. Every loss weakened their ability to protect the carriers and battleships still stationed at their critical base in Tawi Tawi.

Operation A-Go — Japan’s desperate plan to counter the expected American invasion of the Philippines — required precise coordination between those destroyers. But the appearance of an American submarine capable of sinking them so fearlessly threw that plan into chaos.

By late May, Admiral Toyoda had concentrated the full weight of his remaining naval power at Tawi Tawi: four battleships, including the mighty Yamato, nine carriers, fifteen cruisers, and twenty-eight destroyers. It was the largest gathering of Japanese naval strength since Midway. The Americans knew it. U.S. codebreakers had intercepted communications revealing the buildup. And so Admiral Charles Lockwood, commander of the Pacific submarine forces, sent Dealey and Harder into those dangerous waters with a simple directive: “Attack targets of opportunity. Disrupt enemy operations.”

For nine days, Harder prowled the edges of Tawi Tawi undetected, slipping through narrow channels, her periscope barely breaking the surface. The crew operated on adrenaline and nerves, sleeping in short shifts, eating cold rations in the stale air below decks. They were used to it by now — the unending claustrophobia, the smell of oil and sweat, the constant awareness that a single depth charge could crush them like a tin can.

Then, at 0300 on June 6th, a Japanese patrol plane spotted a faint periscope wake north of the anchorage. Within minutes, three destroyers were dispatched to intercept.

By dawn, Commander Dealey had eyes on them through his periscope. Minazuki was leading the formation, sleek and fast, her bow cutting a white wake across the black sea. Behind her, Hayanami and Tanikaze spread wide, sweeping the area in a deadly search pattern.

The men inside Harder were silent, waiting. They knew what was coming.

Dealey kept his voice calm as he issued orders. “Ahead one-third. Bring her bow to zero-nine-zero. Range, eleven hundred yards.” His words carried the kind of authority that made men believe they could survive anything.

Every man in the conning tower understood what he was planning — a down-the-throat shot. It was the most dangerous maneuver in submarine warfare: firing torpedoes straight at a destroyer charging directly toward you. If you missed, the destroyer dropped depth charges right on top of your position. Dive too late, and she’d ram you.

“Stand by tubes one through four,” Dealey ordered.

The sonar operator called out, “Range closing fast — one thousand yards, nine hundred…”

“Fire one,” Dealey said. The torpedo hissed away, then another, and another. “Take her down. Three hundred feet.”

The Harder’s bow pitched sharply as the ballast tanks flooded. Seconds later, a thunderous explosion rolled through the hull, followed by another. Light bulbs shattered overhead. Men were thrown against bulkheads. A third explosion followed, even closer — the shock wave slamming through the steel.

When Dealey brought the periscope back up, the water was littered with debris and oil. Where Minazuki had been, there was only a spreading slick and the faint glow of fire.

The other two destroyers were retreating, dropping depth charges in random panic.

By 0900, word of the sinking reached Admiral Toyoda’s flagship. His fury was immediate. Two destroyers in twenty-four hours — both by the same submarine. He ordered six more destroyers to sweep the area and hunt Harder down. Patrol planes began circling overhead every twenty minutes, their searchlights probing the surface.

But Commander Dealey wasn’t finished.

That night, at 0230, Harder surfaced to recharge her batteries. The sky was overcast, the sea dark and quiet. The men worked quickly, their movements efficient and silent. Then at 0312, the radar operator called out, “Contact bearing zero-nine-five. Range eight thousand yards. Closing fast.”

Dealey moved instantly to the bridge. Through binoculars, he could see the faint silhouette of a ship moving through the dark. Judging by its speed and signature, it was another destroyer — Hayanami, one of the vessels searching for him. Her captain, Commander Hideo Kuboki, had been patrolling since 0100 and was likely exhausted. The destroyer was returning to base, unaware that an American submarine was now stalking her in the dark.

Dealey made his decision in seconds. “Flank speed. Close the range.”

The Harder surged forward on the surface, her twin diesels roaring. The radar scope showed the range closing fast: seven thousand yards, six thousand, five. At four thousand yards, Hayanami’s radar operator finally detected a small, fast-moving contact. They assumed it was another destroyer. By the time they realized the truth, it was too late.

At two thousand three hundred yards, Dealey fired four torpedoes in quick succession. Two struck home. The explosions ripped through Hayanami’s stern, tearing her apart near the aft magazine. The destroyer’s stern sheared clean off, spinning away into the darkness as the rest of the ship rolled violently to port. She sank within minutes.

The Japanese search planes arrived too late.

Two destroyers gone in less than twenty-four hours.

By dawn, Toyoda had withdrawn eight destroyers from convoy escort duty and ordered them into hunter-killer groups, their only mission: find and destroy the submarine haunting the waters off Tawi Tawi. The Imperial Japanese Navy was now diverting critical ships away from protecting their own convoys just to hunt one American commander.

The irony wasn’t lost on Dealey. For the first time in the Pacific war, a single submarine had forced the enemy’s hand — and humiliated them in the process.

By June 8th, Harder was already moving south toward the narrow Sabutu Passage, an area so heavily patrolled that few submarines dared to enter. But Dealey was not like other commanders. The more dangerous the hunt became, the more he wanted to test the limits of what one submarine could do.

That day, his lookout spotted two destroyers moving at twenty-five knots in perfect formation — Tanikaze and an escort. For ninety minutes, Dealey tracked their zigzagging pattern, watching the clock, waiting for the moment they turned toward him. The crew worked in tense silence, every man aware that one miscalculation could mean death.

When the moment came, Harder’s torpedoes fired in quick sequence. One missed. The others struck near the bridge and forward magazine. The resulting explosion was so violent that the concussion could be heard even with the hatches sealed. Tanikaze broke apart in seconds, her bow separating from the hull as both halves disappeared beneath the surface.

Three destroyers in three days.

By now, the entire Japanese fleet was on edge, every destroyer captain ordered to be on maximum alert, their orders simple and absolute: “No retreat. Kill that submarine.”

But Dealey was already setting his sights on something even more daring.

At dawn on June 9th, Harder rose quietly to periscope depth twelve miles southwest of Tawi Tawi. The sea was calm, the sky just beginning to lighten. What Dealey saw through his periscope made every man in the control room freeze — four Japanese destroyers, side by side, sweeping the water ahead of them in a wide search pattern. Their sonar pings echoed faintly through the hull.

He still had eight torpedoes left.

He studied their formation carefully, calculating angles, speed, and distance. The lead destroyer was zigzagging aggressively, but the second one — the one maintaining a steady course — was vulnerable.

“Range four thousand yards,” the sonar operator whispered.

Dealey waited, patient as a hunter.

When the target turned toward him, he gave the order. Three torpedoes fired. Three explosions followed, each one closer than the last. The Japanese ship erupted in a fireball so violent that debris flew hundreds of feet into the air.

In ninety seconds, the destroyer rolled over and vanished.

The other three destroyers immediately converged on Harder’s position, their sonar pings closing in from all sides.

Inside the submarine, every man braced himself, waiting for the first depth charge to fall.

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At 06:47 on June 6th, 1944, Commander Samuel Dei stood in the cramped conning tower of USS Harter, watching three Japanese destroyers cut through the moonlit waters off Tawi Tawi, tracking his submarine with deadly precision. 37 years old, five war patrols, 18 enemy ships destroyed.

 The Imperial Japanese Navy had dispatched Minizuki, Hayanami, and Tanakaz with orders to eliminate the American submarine that had been terrorizing their supply lines for 3 weeks. Until April 1944, American submarines avoided Japanese destroyers. A destroyer moved at 35 knots. A submerged submarine struggled to reach nine.

 Between December 1941 and March 1944, Japanese destroyers had sunk 14 American submarines. Zero American submarines had sunk a Japanese destroyer while both vessels actively engaged in combat. Commander Dei changed that equation on April 13th. When destroyer Ikazuchi charged Harter’s position at flank speed, every officer on the bridge expected Deive and run.

 Instead, he ordered flank speed ahead straight at the destroyer. At 900 yd, Harter fired four torpedoes in a spread pattern. Two torpedoes struck amid ships. The destroyer exploded and sank in 5 minutes. Dele’s radio report became famous throughout the Pacific submarine force. Expended four torpedoes and one  destroyer.

 Admiral Souimu Toyota, commander and chief of the Japanese combined fleet, didn’t find it amusing. Between January and May 1944, Japan had lost 23 destroyers. Operation Ago, the plan to destroy the American invasion fleet at the Philippines required precise coordination. Losing destroyers to submarine attacks disrupted everything.

 By late May, Toyota had concentrated the mobile fleet at Tawi Tawi Anchorage, four battleships including Yamato, nine carriers, 15 cruisers, 28 destroyers, the largest concentration of Japanese naval power since Midway. American code breakers knew they were coming. Admiral Charles Lockwood sent Harter to patrol the waters around Tawi Tawi and attack targets of opportunity.

 For 9 days, Harter operated undetected. Then on June 6th at 0300, a Japanese patrol plane spotted Harter’s periscope wake 15 mi north of Tawi Tawi. Three destroyers responded immediately. If you want to see how De’s aggressive tactics turned out against three destroyers hunting him simultaneously. Please hit that like button.

 It helps us share more forgotten stories about the submarines that changed naval warfare. Please subscribe. Back to Dy. Commander Dei studied the lead destroyer through his periscope. Minizuki 1,250 tons, four 5-in guns. She was closing fast, zigzagging to avoid torpedo attacks. Behind her, two more destroyers spread out in a search pattern, boxing harder into a kill zone.

 De swung Harter’s bow directly at Minizuki. Range, 1100 yd. Time to collision 96 seconds. Every man in Harter’s conning tower knew what down the throat meant. You fire torpedoes straight at an attacking destroyer’s bow, then dive beneath her keel. If your torpedoes miss, the destroyer drops depth charges directly on your position.

 If you dive too late, the destroyer rams you at 750 yd fired three torpedoes. Take her down 300 ft. Carter’s bow dropped at a 30° angle. 40 seconds after firing, two explosions shook Harter so violently that light fixtures shattered. Then a third explosion lifted Harter’s stern 6 ft before slamming back down. Deal climbed to periscope depth.

 Where Minizuki had been, he saw debris and an oil slick. The destroyer had broken in half and was sinking. The other two destroyers were racing away, dropping depth charges at random. Admiral Toyota received the news at 0900. He ordered six more destroyers to find the submarine. By noon, Japanese patrol planes were searching every 20 minutes, but Dilly wasn’t finished hunting. June 7th, 0230.

Harder surfaced to recharge batteries. The night was pitch black. No moon, heavy cloud cover. Perfect conditions at 0312. Radar contact. Single ship bearing 095, range 8,000 yd, closing fast. The contact was moving at 28 knots. Definitely a destroyer.

 Destroyer Hayanami,700 tons, had been searching for American submarines since 0100. Her captain, Commander Hideo Kuboki, had received orders to return to base at 0300. He was exhausted. Nobody expected an American submarine to attack on the surface at night. De ordered flank speed. Harder’s diesel engines pushed the submarine to 21 knots. He was closing the range deliberately.

 Get inside the destroyer’s radar detection range before they spotted you. At 4,000 yd, Hyanami’s radar operator picked up a surface contact. Small, moving fast, probably another destroyer returning to base. At 3,000 yd, Kuboki realized his mistake. American submarine. He ordered flank speed and turned to ram. Too late. At 2300 yd, Dei fired four torpedoes.

 Two struck Hyanami’s starboard side near the aft magazine. The explosion tore the destroyer’s stern completely off. The ship rolled 90°, her propellers still spinning as she went under stern first. Kuboki and 147 sailors died submerged immediately. Japanese patrol planes would arrive within minutes. Two destroyers in 24 hours. The Imperial Japanese Navy was hunting him with everything they had. Admiral Toyota was furious.

 Two destroyers lost in 2 days to the same submarine. He pulled eight destroyers from convoy escort duty and organized them into hunter killer groups. Their only mission, find and destroy the American submarine operating near Tawi Tawi. Every destroyer captain received the same orders. Maximum aggression, no retreat. Kill that submarine.

 On June 8th, DIY took harder south towards Sabutu Passage, the narrow straight between Tawitawi and Borneo. Japanese destroyers patrolled that passage constantly. De wanted to see how many he could sink before they figured out his tactics. At 1400 hours, lookout spotted two destroyers steaming in formation. Tanic Kaz and an unidentified escort.

 Both were moving at 25 knots, conducting a standard search pattern. De studied their movements for 90 minutes. The destroyers were following a predictable zigzag pattern, changing course every 8 minutes. That gave him maybe 30 seconds to set up a shot after each turn. He positioned harder directly in their path and waited. At 16:30, Tanikaz turned toward Harter’s position.

Range 3,000 yd. Dei let her close. 2500 yd 2,000 1,500. At 1,200 yd, he fired four torpedoes at 17-second intervals. The first torpedo missed. The second struck Tanikaz near the bridge. The third hit the forward magazine. The explosion was so massive that Harter’s crew heard it clearly underwater, even with the hatches sealed.

 Tanikaz’s bow section separated from the main hole. Both pieces sank within 3 minutes. The escort destroyer immediately turned and charged Harter’s position, dropping depth charges as she came. Deok Harter deep. 400 ft. The depth charges exploded overhead, shaking the submarine violently, but causing no serious damage.

 After 40 minutes, the destroyer gave up and withdrew. Three destroyers in 3 days. Admiral Toyota was about to make a decision that would change the entire course of the battle of the Philippine Sea. But first, De had one more destroyer to sink.

 And this time, he was going to do it in broad daylight with two Japanese destroyers watching. June 9th 0500. Deok harder to periscope depth 12 mi southwest of Tawi Tawi. What he saw made every man in the conning tower hold their breath. Dead ahead, four Japanese destroyers steaming in line of breast formation, actively searching for submarines. Their sonar was pinging so loud harder sound operator could hear it without headphones.

 De had eight torpedoes remaining. Four destroyers meant he’d get maybe two shots before they overwhelmed them. He studied their formation through the periscope. The lead destroyer was zigzagging aggressively. The second was maintaining a steady course. That was his target. At 0612, the second destroyer turned directly toward Harter’s position. Range 4,000 yd. De waited.

 3,000 2500. At 1,800 yd, he fired three torpedoes. All three struck the destroyer’s port side within 5 seconds of each other. The ship exploded so violently that debris flew 300 ft into the air. She rolled over and sank in 90 seconds. The other three destroyers immediately converged on Harter’s position.

 Dei took her deep 500 ft. Depth charges began exploding overhead. 23 in the first 10 minutes. The lights went out. Emergency lighting kicked in. Hall plates groaned under the pressure. A pipe burst in the forward torpedo room, spraying seawater across the deck.

 Harter’s crew worked in silence, repairing damage while depth charges continued to detonate around them. After 2 hours, the destroyers withdrew. De climbed to periscope depth. The destroyers were gone. Four enemy warships sunk in 4 days. But De wasn’t thinking about his success. He was thinking about his fuel. Carter had burned through 60% of her diesel reserves. She had maybe three more days before she’d have to withdraw to Fremantle.

 Admiral Jizaburo Ozawa, commander of the Japanese mobile fleet at Tawitawi, received reports of the attacks at 1400 hours on June 9th. Four destroyers lost, one submarine. Ozawa did the math. If an American submarine could penetrate his defensive screen this easily, the entire anchorage was vulnerable.

 He sent an urgent message to Admiral Toyota. The mobile fleet needed to depart Tawi Tawi immediately. The Americans knew where they were. Toyota agreed. Operation Ago required the mobile fleet to intercept the American invasion force near the Maranas, but the operation wasn’t scheduled to begin until June 15th. Moving 6 days early meant his carriers would arrive without proper reconnaissance.

 His destroyers would be scattered across multiple patrol zones. his supply lines wouldn’t be established. But staying at Tawi Tawi with an American submarine hunting his destroyers was suicide. On June 10th at0800, the Japanese mobile fleet departed Tawi Tawi. Four battleships, nine carriers, 15 cruisers, 24 destroyers heading northeast toward the Philippine Sea.

 American codereers intercepted the movement orders within hours. Admiral Raymond Spruent, commander of the fifth fleet, adjusted his battle plans accordingly. The early departure gave American carriers an extra day to position themselves for what would become the Battle of the Philippine Sea. Dei knew none of this. On June 10th at 16:30, he spotted two more destroyers patrolling north of Sibutu Passage.

 Both were moving at high speed, conducting an aggressive search pattern. De had five torpedoes remaining, enough for one more attack. At 1715, he fired three torpedoes at the lead destroyer. One struck near the bow. The destroyer slowed but didn’t sink. The second destroyer immediately charged Harter’s position. Deal fired his last two torpedoes. Both missed.

 He had no torpedoes left, no way to defend himself, and a Japanese destroyer bearing down on his position at 32 knots. De ordered emergency deep. Harder’s diving planes bit hard, pushing the submarine down at maximum angle. 300 ft 400 500. The destroyer passed directly overhead. Her propellers churning the water so loudly that Harter’s crew could hear the blades through the hole. Then silence.

 The destroyer was circling back. De knew the pattern. The destroyer would make multiple passes, dropping depth charges on each run until either the submarine surfaced or imploded. Harder had no torpedoes to fight back. No way to damage the destroyer. His only option was to outlast the attack and hope the destroyer ran out of depth charges first. The first pattern dropped at 1723.

Six depth charges exploded in a tight pattern around Harter. The submarine rolled 15° to Starboard. Light bulbs shattered. Men grabbed handholds. A second pattern dropped two minutes later, closer this time. The explosions lifted Harder’s stern and slammed it back down. Cork insulation rained from the overhead.

 A hydraulic line burst in the control room. For 90 minutes, the destroyer hunted harder. 42 depth charges. Most exploded too shallow or too far away, but three came close enough to crack gauge glass and spring minor leaks. Dei kept harder at 500 ft, moving at two knots, making as little noise as possible. Finally, at 1900 hours, the destroyer withdrew.

 She’d exhausted her depth charge supply. De waited another hour before surfacing. The ocean was empty, no destroyers, no patrol planes, just darkness and the sound of diesel engines recharging batteries. Harder limped south toward Fremantle at 8 knots, preserving fuel. She arrived on June 26th after a 17-day patrol.

 The moment Harter tied up at the pier, Admiral Charles Lockwood was waiting. He’d been tracking De’s patrol reports via radio intercepts. Five destroyers attacked, four confirmed sunk, one damaged. In 12 days, the most successful anti-destroyer patrol in submarine warfare history. Lockwood awarded Deth Navy Cross on the spot. Then he asked the question every submarine commander dreaded. Can you do it again? De’s answer was immediate.

Give me torpedoes and I’ll sink 10. Harter’s crew spent July in Fremantle undergoing repairs and resupply. De trained new crew members on down the throat attack tactics. By late July, every submarine commander in the Pacific had studied Harter’s patrol reports. The tactic worked.

 Between June and August 1944, American submarines sank 14 Japanese destroyers using variations of Dele’s aggressive approach. On August 5th, Harter departed Fremantle for her sixth war patrol. She’d been assigned to operate as part of a three submarine wolf pack with USS Hado and USS Hake. Commander Dy was in charge. Their mission, patrol the waters west of Luzon and attack Japanese shipping heading to the Philippines.

 The patrol started well. On August 21st, the Wolfpack intercepted a 16 ship convoy off Palawan Bay. In a coordinated attack, they sank four cargo ships totaling 22,000 tons. On August 22nd, Harter and Hado attacked three coastal defense vessels off Baton. All three sank.

 Harter was credited with destroying two frigots, Matsua and Hiboui. By August 23rd, Hado had expended all her torpedoes and withdrew from the patrol. That left Harter and Hake operating together off Dassal Bay on the western coast of Luzon. Japanese intelligence had tracked the Wolfpack’s movements.

 They knew approximately where the American submarines were operating, and they’d sent something special to deal with them. At 0453 on August 24th, USS Hake submerged 4 miles off Hermoname Island. Through her periscope, she could see harder on the surface, 4,500 yards to the south.

 Both submarines were preparing to attack a damaged Japanese destroyer that Hado had torpedoed the previous day. Then Hake sonar operator heard something that made his blood run cold. Echo ranging. Close. Getting closer. Two Japanese escort ships were closing on Harter’s position. CD22 and mind sweeper PB102 both were moving at 18 knots conducting an active sonar search. They’d been hunting American submarines for 3 days.

 Japanese intelligence had intercepted radio transmissions between Harter Hake and Hado during the Palawan Bay attack. They knew the Wolfpack was operating somewhere off Dal Bay. Hake’s captain immediately ordered his submarine deep and silent. He watched through his periscope as the two Japanese ships closed on Harter.

 At 0520, Hakes radio operator tried to warn Harter. No response. Either Harter’s radio was off or she was already preparing to dive. At 0530, Harter crash dived. The Japanese ships were less than 2,000 yd away. Dei had seen them at the last possible moment. He took Harter down fast, ordering flank speed and maximum dive angle.

 The submarine descended at 35°, her diesel engine still running as she submerged, leaving a massive bubble trail on the surface that pinpointed her exact location. CD22 sonar operator had a perfect contact. Range 1,200 yd, depth approximately 200 ft. Still diving, the escort ship’s captain ordered an immediate depth charge attack. At 0547, CD22 made her first pass over Harter’s position and dropped the full pattern of depth charges set to detonate at 250 ft.

The explosions bracketed Harter perfectly. At least three detonated within 50 ft of her hull. The submarine’s pressure hull cracked near the after torpedo room. Seawater flooded in at tremendous pressure. Harder’s stern flooded completely within 90 seconds. The submarine’s bow rose sharply as the stern dragged her down.

Dy ordered all ballast blown. Emergency surface. The compressed air system fought against the flooding, but there was too much water in the stern compartments. Harder couldn’t reach the surface. At 0552, CD22 made a second death charge run. This pattern hit even closer. The explosions ruptured Harter’s main pressure hull in multiple locations. The control room flooded.

 All electrical power failed. Emergency lighting went dark. At 600 f feet, well below her maximum operating depth, Harder’s hull began to implode. Bulkheads collapsed under pressure. Compartments crushed like tin cans. The submarine was gone in less than 3 minutes from the first depth charge impact. At 0600, CD22 and PB 102 reported a successful kill.

 Large quantities of oil, wood debris, and cork floated to the surface. The Japanese ship circled the area for 2 hours, dropping additional depth charges to ensure the submarine was destroyed. They recovered no survivors. All 79 men aboard Harter, died.

 Commander Samuel Dei, radioman Calvin Bull, who’d earned a bronze star for the destroyer kills in June. Every officer and sailor who’d helped make Harter the most feared submarine in the Pacific. USS Hake remained submerged until nightfall. Her captain filed a contact report describing Harter’s loss. The message reached Admiral Lockwood at 0800 on August 25th.

 Lockwood immediately suspended all submarine operations in the Dassel Bay area and ordered every boat to withdraw to safer waters. The news reached the United States in early September. The Navy Department announced that USS Harter was presumed lost with all hands. No additional details were provided. Submarine operations were classified. The American public wouldn’t learn the full story of Harter’s fifth patrol until after the war ended. But the Japanese knew.

 Admiral Toyota received the report on August 26th. The submarine that had terrorized his destroyer fleet for 3 months was finally gone. He ordered a commendation for CD22’s crew. What Toyota didn’t know was how much damage DY had already done and how his four days in June had changed everything.

 The Battle of the Philippine Sea began on June 19th, 1944, 9 days after Harter sank her fourth destroyer off Tawitawi. Admiral Ozawa’s mobile fleet engaged Admiral Spruent’s fifth fleet in what would become the largest carrier battle in history. 15 American carriers faced nine Japanese carriers. 900 American aircraft against 430 Japanese aircraft. The battle lasted 2 days.

 American pilots shot down 376 Japanese aircraft while losing only 30 of their own. American pilots called it the Great Mariana’s Turkey Shoot. Three Japanese carriers sank. Taihaho, Shokaku, Hio. Two battleships damaged, one cruiser sunk. The Imperial Japanese Navy lost 75% of its carrier air groupoups and would never recover. But the battle might have gone differently if Admiral Ozawa had arrived on schedule.

 His original plan called for the mobile fleet to depart Tawittowi on June 15th. That would have given his reconnaissance planes 4 days to locate the American fleet before the battle began. His carriers would have been fully supplied, his destroyer screens properly organized, his battle plan coordinated with land-based aircraft from the Philippines.

 Instead, Harter forced him to leave 6 days early. Ozawa arrived in the Philippine Sea on June 14th with his fleet scattered across 200 m of ocean. His reconnaissance aircraft had burned through their fuel reserves during the early departure and couldn’t conduct proper searches.

 His destroyers were still regrouping from anti-ubmarine patrols around Tawi Tawi and his supply ships were three days behind schedule. When American carrier aircraft found Ozawa’s fleet on June 19th, his carriers were still launching aircraft. His combat air patrol was undermanned. His fleet formation was disorganized. The great Mariana’s turkey shoot happened because Ozawa wasn’t ready.

 And Ozawa wasn’t ready because Dei had sunk four destroyers in four days and convinced the Japanese that Tawi Tawi was too dangerous. Admiral Lockwood understood this immediately. In his postwar memoir, he wrote that Harter’s fifth patrol was the most strategically important submarine operation of the Pacific War.

 Four destroyers sunk meant four fewer escorts protecting Japanese carriers. But forcing the mobile fleet to depart early meant the entire Japanese battle plan collapsed before the first shot was fired. Between December 1941 and August 1944, American submarines sank 1,314 enemy ships totaling 5.3 million tons. Japanese merchant vessels, cargo ships, tankers, troop transports, but only 29 warships. Most submarine captains avoided warships.

 Too dangerous, too wellarmed, too fast. Dei proved that submarines could hunt warships successfully. His downthroat tactic worked because it violated every assumption Japanese destroyer captains made about submarine behavior. Submarines weren’t supposed to charge destroyers. They were supposed to run. When Harter charged, Japanese captains hesitated.

 That hesitation cost them 12 seconds. 12 seconds was enough time for torpedoes to close the range and strike. By war’s end, American submarines using De’s tactics had sunk 214 Japanese warships, four aircraft carriers, one battleship, nine cruisers, 38 destroyers. The rest were submarines, escorts, and patrol craft. Japan started the war with 63 destroyers. They built 49 more during the war.

 American submarines sank 38. Harder accounted for four of them in 4 days. On March 27th, 1946, President Harry Truman presented Commander Samuel De’s Medal of Honor to his widow, Edwina Dy, in a ceremony on the White House lawn. The citation read in part, “This remarkable record of five vital Japanese destroyers sunk in five short-range torpedo attacks attests the valiant fighting spirit of Commander Dy and his indomitable command.

 The Navy named a destroyer escort after him, USS Dy, commissioned in 1954. She served until 1972. Harder received the presidential unit citation for her first five war patrols. Six battle stars for World War II service. Her motto, hit him harder, became legendary throughout the submarine force. But her real legacy was the tactical revolution she started.

Before Harder’s fifth patrol, submarine doctrine emphasized stealth and evasion. If a destroyer detected you, you ran. You went deep, rigged for silent running, and hoped the depth charges missed. Engaging destroyers in direct combat was considered suicide. The math didn’t work.

 Destroyers were faster, better armed, and designed specifically to kill submarines. Deal changed that math by understanding one critical fact about destroyer captains. They expected submarines to run. When a submarine charged instead, the destroyer captain had to make an instant decision with incomplete information. Turn left, turn right, maintain course, fire guns.

 All while torpedoes closed the range at 46 knots. Most captains chose wrong. By the time they realized their mistake, the torpedoes were already hitting. Between June and December 1944, 12 American submarines adopted DE’s aggressive tactics. USS Tang sank two destroyers. USS Trigger sank one. USS Barb sank one destroyer and damaged another. USS Flasher sank three escort vessels using down the throat attacks.

 The tactic’s success rate was 63%. For every five attacks, submarines sank three destroyers and damaged one more. Only one in five attacks failed completely. Japanese destroyer captains adapted. By late 1944, they developed counter tactics.

 When a submarine charged, destroyers would turn away and circle back, forcing the submarine to expose her broadside to torpedo attacks from other destroyers in the formation, or they’d slow down deliberately, letting the torpedoes pass ahead while closing for a ram. The tactic still worked, but the success rate dropped to 40%. American submarine losses increased. Between August and December 1944, nine submarines were lost to destroy her attacks.

 Tang sank on October 24th when her own torpedo circled back and hit her. Harder went down on August 24th. Darter ran a ground on October 23rd while pursuing a destroyer. But even with higher losses, submarines were sinking more enemy ships than ever before. The aggressive tactics worked. Admiral Lockwood faced a difficult choice.

 recall all submarines and return to defensive tactics or accept higher losses in exchange for destroying Japan’s convoy system completely. He chose aggression. Between January and August 1945, American submarines operating under aggressive patrol doctrines sank 437 Japanese merchant ships and 53 warships. By August, Japan had less than 25% of the merchant tonnage it started the war with. The home islands were starving. Factories were shut down for lack of raw materials.

 The Imperial Japanese Navy couldn’t fuel its remaining ships. Dei never saw any of this. He died 3 months after his greatest victory. Killed by the same type of escort ship he’d spent a year learning to destroy. But his tactics continued. Every submarine commander in the Pacific studied Harter’s patrol reports. Every attack plan referenced the downthroat doctrine. Every torpedo solution included calculations for charging destroyers.

 On May 22nd, 2024, 80 years after she sank, an underwater exploration team led by Tim Taylor and the Lost 52 project discovered Harder’s wreck in the South China Sea. She sits upright on the seafloor at a depth of 3,750 ft, 12 mi west of Daol Bay, where she made her last dive. Her pressure hole remains mostly intact except for depth charge damage near the conning tower.

The wreck is a protected war grave. No salvage operations are permitted. But finding Harter meant something more than locating a shipwreck. It meant bringing closure to families who’d waited 80 years for answers. And it meant honoring 79 men who changed naval warfare forever.

 Today, Harter’s story lives on in unexpected ways. At the United States Naval Academy in Annapapolis, Maryland, submarine tactics instructors still teach the down the throat attack as a case study in aggressive warfare. Not because modern submarines use the same tactic. Modern torpedoes are wireg guided and don’t require close-range attacks, but because dele’s approach demonstrates a fundamental principle.

When your enemy expects you to run, charging often works better than hiding. The Naval History and Heritage Command maintains Harder’s complete patrol reports in their archives. Every radio message, every torpedo firing solution, every depth charge attack. Researchers studying submarine warfare in the Pacific can trace exactly how Developed his tactics across six war patrols.

 His reports show a commander who learned from every encounter, refined his approach constantly, and never stopped looking for ways to sink more enemy ships. Commander De’s grave is at Arlington National Cemetery in section 59, grave 874. His headstone lists his rank, his dates of service, and one line, Medal of Honor, Destroyer Killer.

Families of Harter’s crew visit every year on August 24th, the anniversary of her sinking. They place flowers. They share stories about grandfathers and great uncles who died at 22 or 25 or 37, fighting a war most of them never expected to survive. The 79 men aboard Harter came from 38 states.

 Farm boys from Iowa, factory workers from Michigan, college graduates from California. They volunteered for submarine duty knowing the casualty rates. 22% of submariners who served in World War II died. That’s the highest percentage of any branch of the American military. They knew the odds. They served anyway. Calvin Bull, the radio man who earned a bronze star for his role in sinking five destroyers, was 24 when he died.

 John Mau, who survived Harter sinking and later became an admiral, spent 50 years telling their story. He died in 2010 at age 90. The last survivor of Harter’s crew, Paul Bryce, died in 2022 at age 98. With his death, no one who served aboard Harter remains alive to tell their story firsthand. That’s why stories like this matter.

 These men left behind patrol reports and radio messages and Medal of Honor citations. But those documents can’t convey what it felt like to charge a destroyer at flank speed or hear depth charges exploding overhead or watch your captain make decisions that meant life or death for everyone aboard.

 The official history tells us Harter sank four destroyers in 4 days. It doesn’t tell us about the fear or the exhaustion or the absolute certainty that this patrol might be your last.