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

Down the Throat: The USS Harter and the Destroyer-Killing Tactic That Changed Submarine Warfare

It was 1:50 a.m. on May 19th, 1944, and Commander Samuel Dei stood in the cramped conning tower of the USS Harter, staring out into the black waters off Tawi Tawi. The sonar operator’s voice crackled through the radio, announcing that three Japanese destroyers—Minizuki, Hayanami, and Tanakaz—were bearing down on the Harter. These destroyers were on a hunt, a hunt that had already claimed the lives of several American submarines, and now they were targeting Dei’s boat. The odds were clear: if Harter didn’t act fast, they would be sunk within minutes.

Dei, only 37 years old and on his first war patrol as commanding officer, had already sunk 18 enemy ships. But this was different. The Japanese destroyers were faster, better armed, and deadly accurate. For years, American submarine doctrine had been built around avoiding destroyers—submarines were meant to run, dive deep, and evade. But not anymore. Commander Dei had already proven he could turn the tables on these destroyers, something no other submarine captain had dared to try before.

In a previous engagement, just a month earlier, he had charged a Japanese destroyer, the Ikazuchi, head-on, in a move that shocked both his crew and the enemy. At 900 yards, he fired four torpedoes in a spread pattern, sinking the destroyer in minutes. His radio report became famous throughout the Pacific submarine force. “Expended four torpedoes, and one destroyer.” Admiral Soimu Toyota, commander of the Japanese combined fleet, wasn’t amused.

By May, the Japanese had deployed a formidable fleet, with four battleships, nine carriers, and 28 destroyers stationed at Tawi Tawi. They were ready to destroy the American forces advancing toward the Philippines. The United States had decoded Japanese transmissions and learned of the Japanese fleet’s movements. Commander Lockwood of the Pacific Fleet sent Harter and two other destroyer escorts to patrol the waters off Tawi Tawi, hoping to disrupt the enemy’s plans.

For nine days, Harter sailed undetected, waiting for an opportunity to strike. At 3:00 a.m. on June 6th, a Japanese patrol plane spotted Harter’s periscope wake 15 miles north of Tawi Tawi. Immediately, three destroyers were dispatched to hunt the American submarine. Dei knew the odds weren’t in his favor, but he was ready. The battle was going to be fast, and his next move would define the future of submarine warfare.

As the Japanese destroyers closed in, Dei and his crew prepared for the attack. The sonar operator reported that Minizuki, the lead destroyer, was closing in fast, zigzagging to avoid torpedo attacks. Dei had a plan. He positioned Harter directly in the path of the oncoming destroyers, knowing he had just a few seconds before they would be within firing range.

Dei ordered, “Flank speed ahead, and prepare to fire.” The crew understood what that meant: they were charging straight at a Japanese destroyer—no evasion, no running. It was a high-stakes gamble, but it was the only choice. At 1,100 yards, Harter fired three torpedoes in a perfect spread, then immediately dove deep to avoid the inevitable retaliation.

The explosion from the first torpedo strike was massive. The Minizuki was hit amidships, and within minutes, it sank. Harter’s crew could feel the force of the explosion even through the thick steel hull. The destroyer had been destroyed. The remaining two Japanese ships tried to flee, dropping depth charges at random in an attempt to cover their retreat. But the damage was done. The Minizuki was gone, and Harter had just proven that American submarines could fight destroyers head-on and win.

The other two destroyers, knowing their comrades had been sunk, retreated, dropping depth charges as they fled. Harter went deep to avoid the incoming blasts. For 40 minutes, Harter held her position, her crew tense, listening as the depth charges exploded overhead, shaking the boat with each burst. But after the intense barrage, the destroyers retreated. Harter had survived the attack and had sent a clear message to the Japanese—Harter was no longer just an elusive threat; it was a hunter.

The next day, Commander Dei and his crew began preparing for the next engagement. The Japanese were not giving up. Six more destroyers were dispatched to find and destroy Harter. The pressure was on—five kills in five days was unheard of, and the Japanese were growing desperate.

On June 7th, as Harter surfaced to recharge its batteries, a new radar contact appeared. A Japanese destroyer, Hayanami, was closing in fast. The destroyer had been searching for American submarines since 1:00 a.m. but had failed to locate any. At 3:12 a.m., Hayanami’s radar finally picked up the small submarine speeding toward it. The Japanese commander immediately ordered full speed ahead and turned to ram.

But Commander Dei was already ahead of him. At 2,000 yards, he ordered the Harter to charge. Hayanami, unaware of Harter’s approach, was too late to react. At 1,800 yards, Dei fired four torpedoes. Three hit the destroyer’s port side, causing a massive explosion. The ship rolled, its propellers still spinning as it sank. The crew was lost. The Japanese fleet had just suffered its second major blow in less than 24 hours.

Dei’s reputation as a destroyer killer was solidifying, and his tactics were proving devastating to the Japanese. But Harter wasn’t finished. There was still more to come.

On June 9th, Harter tracked two more Japanese destroyers patrolling the Sibutu Passage. They were moving fast, zigzagging as they searched for American submarines. Dei had learned from previous attacks. He knew the destroyers’ movements were predictable, and this time, he was ready. He positioned Harter in their path, waiting for the right moment.

At 4:30 p.m., the lead destroyer, Tanikaz, turned toward Harter‘s position. At 1,200 yards, Dei fired three torpedoes. The first torpedo missed, but the second struck Tanikaz near the bridge, and the third hit the forward magazine. The explosion was so intense that Harter‘s crew could feel it underwater. The destroyer’s bow separated from the hull, and both sections sank within minutes. The remaining destroyers retaliated, dropping depth charges, but once again, Harter had survived. Three destroyers sunk in three days.

As the Japanese Navy began to regroup, Admiral Toyota was furious. The Harter had destroyed four of his destroyers in four days, and his fleet’s defensive capabilities were seriously compromised. Toyota knew that he had to act quickly. He ordered his remaining destroyers to increase their patrols, searching relentlessly for the American submarine.

On June 10th, Harter was tracking two more Japanese destroyers, RO 105 and RO 109. This time, however, the Japanese had learned from the previous attacks. They had adopted new tactics to avoid American torpedoes. They used more aggressive evasive maneuvers and went deeper to avoid detection. But Commander Dei wasn’t fooled. He had tracked these patterns before and knew what to expect.

At 5:15 p.m., Harter fired its remaining torpedoes. This time, the attack wasn’t as successful. One destroyer was hit, but the second one managed to escape. Yet again, the Japanese forces were forced to adjust their tactics. They were starting to fear the Harter.

By the end of June, Harter had sunk five Japanese destroyers in 12 days—an unprecedented record for a single submarine. The attack had not only crippled the Japanese destroyer fleet but also forced their entire mobile fleet to retreat early, disrupting their plans for the Battle of the Philippine Sea. The damage done by Harter’s torpedoes had changed the entire course of the Japanese Navy’s strategy.

Admiral Lockwood, upon hearing the news, awarded Commander Dei the Navy Cross. He also issued a direct order: “Can you do it again?” Dei’s response was confident, “Give me torpedoes and I’ll sink 10.”

But the Harter wouldn’t have to prove itself again in the same way. The Japanese would start learning from their mistakes. On August 24th, Harter was struck by a Japanese destroyer, and the submarine went down, taking Commander Dei and 78 crew members with her.

The story of the USS Harter and Commander Samuel Dei’s legacy lives on today in the annals of naval history. Despite the loss of Harter, the tactics pioneered by Dei—charging destroyers head-on, using aggressive tactics instead of stealth—changed submarine warfare forever. The Japanese Navy had never seen such an approach, and it was one that turned the tide of the war in the Pacific.

Dei’s legacy is one of calculated risk, brilliant tactics, and unmatched courage under pressure. Today, his work is studied in naval academies around the world. His decisions, his leadership, and his willingness to break from tradition saved countless American lives and inflicted devastating losses on the Japanese fleet. The story of the USS Harter and its crew is a testament to the bravery and ingenuity of the men who fought to secure victory.

Note: Some content was generated using AI tools (ChatGPT) and edited by the author for creativity and suitability for historical illustration purposes.