Japanese Mocked This “Failed” Torpedo — Until It Destroyed Japan’s Biggest Cruiser in 30 Seconds 

Japanese Mocked This “Failed” Torpedo — Until It Destroyed Japan’s Biggest Cruiser in 30 Seconds 

At 0335 on October 25th, 1944, Lieutenant Junior Grade Isidor Kovar stood on the bridge of PT137, watching a Japanese destroyer slice through the black waters of Suragal Strait. 24 years old, 7 months commanding patrol torpedo boats, zero capital ships damaged. Vice Admiral Shima’s Southern Force had just entered the straight with two heavy cruisers, one light cruiser, and four destroyers.

Over 40,000 tons of Imperial Japanese Navy steel. Kovar’s boat was blind. PT-137’s auxiliary generator had failed 3 hours earlier, leaving the 80oot Elco boat without radar or radio transmission. No way to see targets beyond visual range. No way to coordinate with the other 38 PT boats scattered along the straight.

 His crew of 12 sat in darkness, relying on moonlight and lightning flashes to spot enemy ships. The night belonged to the Japanese. Admiral Shima’s force was racing north to support Vice Admiral Nishimura’s battleships in their assault on the American beach head at Ley Gulf. If they broke through, 20,000 American troops would face bombardment from 14-in naval guns at dawn.

 PT boats had been dying all night. Lieutenant Commander Robert Leon’s section had attacked Nishimura’s force 2 hours earlier. PT 152 had taken a direct hit from destroyer Shagur, killing one gunner and setting the boat ablaze. PT130’s radio had been demolished by shellfire. The boats that survived reported the same problem.

 Japanese destroyers spotted PT boats first, illuminated them with search lights, then destroyed them with 5-in guns before the Americans could launch torpedoes. Kovar had already fired once tonight. At 0115, he’d spotted two Japanese destroyers passing south of Panon Island. He closed to 800 yd, lined up his shot, and launched one Mark 8 torpedo.

 The 21-in fish ran true for 15 seconds, then porpused, leaping out of the water like a dolphin before diving deep. The torpedo missed a stern. The destroyers never knew PT-137 existed. That was the problem with Mark 8 torpedoes. Designed in 1938, powered by a wet heater engine burning 180 proof grain alcohol mixed with compressed air.

Temperamental depth control. The torpedoes were supposed to run at 10 ft below the surface. Instead, they ran shallow or deep depending on water temperature, manufacturing tolerances, and luck. PT boat crews called them swimming slot machines. The United States Navy had built 326 Elco 80 ft PT boats by October 1944.

Wooden hulls made of 2-in mahogany planks. Three Packard 12-cylinder engines producing 4500 horsepower total. Top speed 41 knots in calm seas. Armed with four Mark18 torpedo tubes, two twin 50 caliber machine gun turrets, one 20mm Orlicin cannon, and depth charges. Crew complement, three officers, 14 enlisted men, though most boats operated with 12 to 14 total.

 But the torpedoes were the weapons that mattered. Each Mark 8 weighed 2,215 lb and carried 466 lb of torpex explosive, 50% more powerful than TNT. A single hit could a cruiser or sink a destroyer. The problem was getting hits. Mark 8 torpedoes had a documented failure rate of 30%. Some ran circular, some sank to the bottom, some exploded prematurely.

 The ones that worked had to be launched from less than a thousand yards, close enough that Japanese search lights could blind PT boat crews, and 5-in shells could tear wooden holes apart. Kovar watched the destroyer silhouette sharpen against the darkness. The Japanese ship was heading south, running at 20 knots, no zigzag pattern, probably damaged or separated from Admiral Shima’s main force, a straggler.

 If you want to see how Kovar’s blind torpedo shot turned out, please hit that like button. It helps us share these forgotten stories with more people. And please subscribe. Back to Kovar. He had three torpedoes remaining, range closing to 900 yd. The destroyer hadn’t spotted PT-137 yet. Kovar’s boat set low in the water, painted dark gray, with its engines throttled down to reduce wake.

 The Japanese lookouts were scanning north, watching for threats from Admiral Oldenorf’s battle line. Kovar made his decision. He ordered his crew to battle stations without speaking using hand signals in the darkness. Torpedo man second class checked the tubes. Gunners swung their 50 caliber turrets to cover the destroyer search lights.

 Engineman stood ready to run the packards to full power for the escape. 900 yd. Kovar centered the destroyer in his sight. His thumb moved to the torpedo launch trigger. He had one shot. If the Mark 8 ran true, he might damage a destroyer. If it ran deep or shallow, he’d launched $1,500 worth of explosives into empty water.

 And if the destroyer spotted PT-137’s torpedo wake, search lights and shells would follow within seconds. Kovar pressed the trigger. The Mark1 18 tube fired with a pneumatic hiss. The torpedo dropped into the water and its wet heater engine ignited, leaving a phosphorescent wake that glowed green in the darkness. Kovar counted seconds.

 At 41 knots, the Mark 8 would reach the destroyer in 23 seconds if it ran straight, if it ran at all. The torpedo disappeared beneath the surface. No porposing, no circular run. The wake tracked true toward the destroyer’s midship section. Kovar kept his eyes on the target, waiting for the flash of torpex detonating against steel. Nothing happened.

 The destroyer steamed past the torpedo’s track without slowing. No explosion, no fire, no damage. Kovar had missed. Another Mark 8 had failed. His crew stood silent on the deck, watching $1,500 of American ordinance vanish into Sural Straight. Then the night erupted behind the destroyer. A massive explosion lit the water 800 yd beyond the Japanese ship.

Yellow orange flame shot 200 ft into the air. The concussion wave hit PT137 3 seconds later, a physical blow that rattled the boat’s wooden hull and knocked one gunner off his feet. Kovar grabbed the windscreen to stay upright. Something big had just died. The destroyer search light snapped on, sweeping across the water toward PT 137.

The beam caught the PT boat in its glare. Kovar shouted for full power. His enginemen slammed the three Packard engines to maximum throttle. 4,500 horsepower roared to life. Star shells burst overhead. Japanese illumination rounds hung suspended on parachutes, turning night into day. Kovar could see his entire boat lit up like a target at a shooting range.

 He ordered hard starboard, throwing PT-137 into a violent turn. The first 5-in shell hit the water 30 yard to port. The second shell hit 50 yards a stern. The destroyer was firing blind, trying to bracket the PT boat with high explosive rounds. Each shell displaced two tons of water when it detonated, creating geysers that drenched Kovar’s crew.

 PT 137 reached 40 knots. The wooden hull pounded across the waves, vibrating so hard that instruments shook loose from their mounts. Kovar steered toward a thick bank of smoke that hung over the straight. residue from the night’s earlier battles. If he could reach the smoke before the destroyer’s guns found their range, his boat might survive.

 The third shell missed by 20 yards, the fourth by 15. The Japanese gunners were walking their fire closer. Kovar counted the seconds until the fifth shell would land directly on his boat. PT-137 hit the smoke bank at 41 knots and disappeared. The star shells still burned overhead, but the thick black smoke concealed the wooden boat from Japanese gunners.

 Kovar maintained full speed for two minutes, then throttled back and changed course to northeast. The destroyer’s guns fell silent. Either they’d lost the target or they’d moved on to other threats. Kovar’s radio man worked frantically to restore the auxiliary generator. After 10 minutes of rewiring connections in the dark, power returned.

 The radar screen flickered to life. The radio crackled with traffic from other PT boats. The explosion Kovar had witnessed wasn’t his imagination. Someone had transmitted a contact report. Light cruiser hit. Dead in water. Listing to port. Location southern entrance to Sural Straight. Time 0336. One minute after Kovar had fired his torpedo, but Kovar had shot at a destroyer. his Mark 8 had missed.

 He’d watched the torpedo pass harmlessly a stern of the Japanese ship. There was no cruiser in his firing solution, no secondary target beyond the destroyer, unless the torpedo hadn’t missed, unless it had run deep, deeper than the destroyer’s 5-ft draft, and continued traveling through the water until it found a larger ship with a deeper hull.

Radio traffic confirmed details. The cruiser was Abukuma, flagship of destroyer squadron 1. Nagara class light cruiser, 5,570 tons, hit in the number one boiler room, 37 crew dead, speed reduced to 10 knots. The cruiser had fallen out of Admiral Shima’s formation and was attempting to retreat south.

 Kovar’s torpedo hadn’t failed. It had run exactly as designed at depth. Too deep for the destroyer, which drew only 5 ft of water, but perfect for Abukuma, which drew 16 ft. The Mark 8 had passed under the destroyer and struck the cruiser 900 yd beyond. A failed shot had become the most significant hit by an American PT boat in the entire Pacific War.

 But Abukuma was still afloat, still armed with seven 5-in guns and eight torpedo tubes, still capable of 20 knots if her engineers could contain the flooding. And Kovar’s PT-137 sat in Japanese controlled waters with two torpedoes remaining and a generator that had already failed once tonight. Dawn was 3 hours away.

 Admiral Shima’s force continued north into the killing zone that Rear Admiral Jesse Oldenorf had prepared. Six American battleships waited across the northern exit of Surugal Strait with their main batteries loaded and gun directors locked on radar contacts. Eight cruisers flanked the battleships.

 26 destroyers prowled the flanks ready for torpedo runs. Vice Admiral Nishimura’s force had already been destroyed. Battleship Yamashiro had taken multiple torpedo hits and capsized at 0419, taking 1,636 crew to the bottom. Battleship Fusso had broken in half and sank. Only destroyer Shigur survived from Nishimura’s seven ship force.

 Admos Shima never reached the American battle line. At 0425, his flagship Nachi collided with the burning wreck of cruiser Moami in the smoke and darkness. The collision tore a 40ft gash in Nachi’s bow and jammed her starboard propeller shaft. Speed reduced to 18 knots. Admiral Shima ordered his entire force to retreat south.

 The Japanese were running, but Abukuma couldn’t run with them. The torpedo hit had flooded Abukuma’s forward boiler room. Salt water poured through the 16 ft hole in her portside hole. Damage control team sealed the watertight doors containing the flooding to two compartments. But the cruiser had lost one of her four boiler rooms.

 One quarter of her power plant was gone. Her bow settled 4 ft deeper in the water, creating drag at further reduced speed. Captain Hanata Takuo fought to save his ship. His engineers rerouted steam from the three remaining boilers. Pumps worked continuously to control flooding. Repair crews welded steel plates over smaller hole fractures.

 By 0445, 90 minutes after the torpedo hit, Abukuma’s speed had increased from 10 knots to 20 knots. Not enough to keep pace with Admiral Shima’s heavy cruisers, but enough to escape Surugal straight before American battleships could range her with their 14-inch guns. Abukuma turned south at 0500, following destroyer Ushio through the smoke- fil straight.

 The cruiser was down at the bow, listing 3° to port, but she was under her own power. Captain Hanata ordered his crew to jettison unnecessary weight. 50 caliber machine gun ammunition went overboard. Spare parts followed. Anything that wasn’t essential for keeping Abukuma afloat and armed. PT boats shadowed the retreating Japanese ships.

 Lieutenant Commander Robert Leon’s PT134 reported Abukuma’s position at 0600. The cruiser was making 20 knots south, trailing oil, but still dangerous. Her seven 5.5 in guns remained operational. Her torpedo tubes were loaded. American PT boats that attempted close approaches were driven off by accurate defensive fire.

 By 06:30, Abukuma had cleared Sural Strait and entered the Mindanao Sea. The cruiser turned west toward Dapitan, a small port on Mindanao’s northern coast where emergency repairs could be attempted. Captain Hanata calculated arrival time at,400 hours, 8 hours to reach safety, 8 hours to keep his ship from sinking. The battle of Surugal Strait ended at 0700 on October 25th.

 The Imperial Japanese Navy had lost two battleships, three destroyers, and suffered heavy damage to three cruisers. American losses, one PT boat sunk, several damaged. It was the last battleship engagement in naval history and a complete American victory. But the battle wasn’t finished for Abukuma. The cruiser had survived the torpedo hit.

She’d escaped the straight. She’d maintained enough speed to run south ahead of American pursuit. Captain Hanata had kept his crew disciplined and his ship functional despite catastrophic damage. Abukuma reached Dapitan Harbor at 14:30 hours on October 25th. Repair crews went to work immediately welding steel patches over the torpedo hole and pumping out flooded compartments.

 The cruiser would need 3 days of emergency repairs before attempting the run back to Japan. 3 days anchored in Philippine waters. Vice Admiral Thomas Concincaid, commander of the US 7th Fleet, received contact reports on Abukuma throughout October 25th. The damaged cruiser represented unfinished business. Concincaid ordered Rear Admiral Thomas Sprag to locate and destroy all retreating Japanese ships from the battle of Suriga Strait.

 Sprag commanded 18 escort carriers operating east of Lee Gulf. His air groupoups had been fighting Vice Admiral Tao Kurita’s center force all morning in the desperate battle off Samar, but by afternoon Kurita had retreated. Sprag’s aircraft were available for search and strike missions. At 1500 hours on October 25th, Sprag dispatched scout aircraft to locate Admiral Shima’s retreating force.

 The search pattern covered waters from Sural Strait west to the Sulu Sea. Priority target, damaged cruisers attempting to reach safe harbors. Abukuma sat in Dapitan Harbor with her engines shut down for repairs. No air cover, no destroyer screen, just one escort, destroyer Ushio, and repair crews working frantically to patch a 16 ft hole below the water line.

 October 26th dawned clear. Perfect weather for carrier aircraft. Perfect hunting conditions for American dive bombers searching for crippled Japanese ships. 17 Grumman TBM Avenger torpedo bombers from rear Admiral Sprag’s escort carriers found Admiral Shima’s force at 0900 on October 26th. The American aircraft spotted heavy cruisers Nachi and Ashigata steaming west at 25 knots screened by four destroyers.

 The cruisers were undamaged and combat capable, defending themselves with concentrated anti-aircraft fire. The Avengers attacked but scored no hits. Shima’s main force would escape. But the scout aircraft had also spotted something else. Radio transmission at 0915. Crippled cruiser anchored in harbor. Coordinates matching Dapeton.

Ship identification. Nagara class light cruiser. Estimated 5,000 tons. One destroyer escort, no air cover. The cruiser sat dead in the water with visible damage to her bow section. The 13th Air Force received the contact report at Clark Field on Luzon. The fifth Air Force received it at Moratai. Both commands had B24 Liberator heavy bombers available for immediate strikes.

The consolidated B-24 was America’s most produced heavy bomber. 18,500 aircraft built by October 1944. Four Pratt and Whitney engines. Maximum speed 300 mph. Combat radius 1,000 miles. Bomb load 8,000 lb. 44 B24 Liberators launched from Philippine and Moritai air bases at 1000 hours on October 26th.

 Their mission sink the damaged cruiser before she could complete repairs and escape to Japan. The bombers formed up in flights of four to six aircraft and headed for Dapitan. Abukuma’s lookouts spotted the first flight of B-24s at 12,200 hours. Six 4enine bombers approaching from the northeast at 12,000 ft. Captain Hanata ordered his crew to battle stations.

 The cruiser’s anti-aircraft batteries consisted of four twin mount type 96 25mm guns and 10 single-mount 25mm guns, 38 barrels total. Effective range 3,000 ft. The guns were designed to defend against dive bombers attacking from 6,000 ft or below. They were nearly useless against level bombers attacking from 12,000 ft.

 Destroyer Usio added her anti-aircraft fire, another four twin mount and four single-mount 25mm guns, but Ushio was a Fubuki class destroyer built in 1929. Her anti-aircraft armament was inadequate for 1944 aerial warfare. The first flight of B-24s approached from the northeast. Each bomber carried 12 500-lb generalpurpose bombs. 72 bombs falling from 12,000 ft.

The bombarders used Nordon bomb sights, calculating for wind speed, altitude, and target motion. Abukuma couldn’t maneuver. The cruiser sat anchored with her engines offline for repairs. The first bombs fell at 12:07. Captain Hanata watched them drop. small black dots growing larger as they accelerated downward.

 The bombs took 22 seconds to fall from 12,000 ft. 22 seconds to track their trajectory and realize his ship had no escape. Three bombs hit Abukuma. The first struck near the stern, penetrating the deck and detonating inside the after engine room. The explosion killed 14 engineers and destroyed the cruiser’s starboard propeller shaft.

 The second bomb hit Amid ships, blowing a 20ft hole through the main deck and igniting aviation fuel stored for Abukuma’s Type 94 reconnaissance float plane. Fire spread through three compartments. The third bomb struck forward, detonating in the crew quarters and killing 31 sailors. Abukuma was dying. Three direct hits from 500 lb bombs had opened her hull in multiple locations.

 The fires couldn’t be controlled. The flooding couldn’t be stopped. Captain Hanata knew his ship had minutes remaining. More B-24s appeared. Second flight, third flight. The American bombers circled Dapitan Harbor, lining up for follow-up attacks. They could see Abukuma burning and listing. They could see crew abandoning ship.

 But the mission called for confirmation of sinking, not just damage. The second wave dropped 48 more bombs. Four additional hits struck the doomed cruiser. One bomb detonated in the Ford magazine where Type 93 Longance torpedoes were stored. The torpedo warheads contained 1,080 lb of explosives. When the bomb hit triggered a sympathetic detonation, the explosion tore Abukuma’s bow completely off.

 The cruiser lurched forward, her severed bow section sinking immediately. The stern section rose out of the water, propellers exposed to air. Abukuma’s hull broke in half amid ships. Both sections began their final plunge. Captain Hanata gave the order to abandon ship at 12:25. The crew had 18 minutes to get off a ship that was breaking apart and sinking.

 330 men remained alive. They jumped into Dapitan Harbor and swam toward destroyer Ushio, which maneuvered to pick up survivors. Abukuma disappeared at 12:42 on October 26th, 1944. 1 day and 9 hours after Lieutenant Junior Grade Isidor Kovar’s torpedo had struck her in the darkness of Sural Strait.

 250 crew died, 37 in the torpedo hit, the rest in the bombing. Destroyer Ushio rescued 283 survivors, including Captain Hanata. The B24s returned to their bases, reporting one Nagara class cruiser sunk. Lieutenant Junior Grade Isidor Kovar returned to base at Takoban Ley on October 26th. His afteraction report documented one torpedo fired at a Japanese destroyer at 0335 on October 25th. Target: Destroyer.

 Estimated 1500 tons. Result: miss a stern. No observed hits, no confirmed damage. Kovar didn’t claim to have struck Abukuma. He’d watched his torpedo pass under the destroyer. He’d seen no explosion on his intended target. The massive blast 800 yd beyond the destroyer had occurred in smoke and darkness. Kovar couldn’t confirm what his torpedo had hit, if anything.

 39 PT boats had operated in Sural Strait that night. They’d launched dozens of torpedoes at Japanese ships. Multiple boats reported explosions. Multiple boats claimed possible hits. The chaos of night combat with radar failures, radio failures, smoke, and Japanese star shells made accurate observation nearly impossible. Commander Selman Bowling commanded motor torpedo boat squadron 21.

 He faced a puzzle when reviewing afteraction reports from the Battle of Sural Strait. Several PT boat crews claimed hits on Japanese warships. Some claims overlapped, some contradicted each other. The darkness, rain squalls, and confusion caused by enemy gunfire made precise observation impossible. Bowling noted that stated times in the action reports might be wrong by 15 to 30 minutes.

 Estimated numbers and types of enemy ships weren’t considered accurate, but someone had hit Abukuma. Japanese records recovered after the war confirmed the light cruiser had taken a torpedo hit at 0325 on October 25th. Location southern entrance to Suraga Strait near Bennett Point on Panahan Island. The torpedo struck Abukuma’s port side near the number one boiler room.

 37 crew killed instantly. American naval intelligence began cross-referencing PT boat positions with Japanese damage reports. Only three PT boats have been operating near Bennett Point at 0325. PT-134, PT 132, and PT 137. Lieutenant Commander Leon’s PT-134 had fired its last torpedo earlier, missing a destroyer, and St. Jones’s PT-132 had expended four torpedoes against another destroyer, all missing. That left PT137.

Kovar’s report documented firing one torpedo at 0335, 10 minutes after the Japanese recorded Abukuma’s torpedo hit, but Kovar had noted that his boat’s chronometer might be inaccurate. Without functioning radar or radio, PT-137 had relied on a mechanical clock for time references. The 10-minute discrepancy fell within normal clock error.

 The firing position matched. PT-137 had been 900 yd from a destroyer heading south near Panan Island. Japanese records showed Abukuma had been steaming south at that location, screened by destroyers. The geometry aligned perfectly. Kovar’s torpedo had been aimed at a destroyer in the foreground. It ran deep, passed under the destroyer’s shallow draft, and continued until it struck Abukuma’s deeper hull 900 yd beyond.

 The United States Navy officially credited Lieutenant Junior Grade, Isidador Michael Kovar, and PT-137 with sinking JN Abukuma. The confirmation came months after the battle following detailed analysis of American action reports and captured Japanese records. Abukuma became the largest warship whose destruction was credited primarily to an American PT boat.

 The 5,570 ton cruiser displaced more than any other capital ship sunk by PTO torpedo attack in the Pacific War. Previous PTBO successes had been against destroyers, destroyer escorts, and smaller craft. No American PT boat had ever destroyed a light cruiser before Kovar’s accidental hit.

 The Navy Cross was awarded to Lieutenant Junior Grade Isidor Michael Kovar for extraordinary heroism during the Battle of Sural Strait. The citation recognized his aggressive attack against superior enemy forces under intense fire. Kovar had closed to 900 yards of Japanese warships without radar or radio, launched a torpedo under star shell illumination, and escaped under 5-in gunfire.

 The accidental nature of his hit wasn’t mentioned in the citation. The Navy Cross recognized courage and tactical execution, not luck. 326 Elco 80oot PT boats served in World War II. They conducted thousands of patrols in the Pacific and European theaters. They rescued down pilots. They raided enemy supply lines. They fought Japanese destroyers and German eboats.

They evacuated General Douglas MacArthur from Corgodor. They carried Army Rangers on covert raids. They sank enemy barges, sand pans, and small craft by the hundreds. But only one PT boat destroyed a 5,000 ton cruiser. Only one PT boat fired a torpedo that ran under the intended target and struck a capital ship beyond.

 Only one PTBOT commander earned a Navy Cross for a shot he believed had missed. PT-137 survived the war. The boat continued combat operations in the Philippines through early 1945, conducting 53 more patrols after the Battle of Surow Strait. Lieutenant Junior Grade Kovar remained in command through March 1945 before rotating back to the United States.

 The Mark 8 torpedo that struck Abukuma represented manufacturing lot 237 produced at the Naval Torpedo Station in Newport, Rhode Island in August 1944. Serial number 11847. Cost to manufacture $1,500. Value of the target destroyed estimated $40 million in 1944 currency. That torpedo had a problem. It ran deep.

 The Mark 8 torpedo had been designed to run at 10 ft below the surface. Depth control was managed by a hydrostatic valve connected to horizontal rudders. As the torpedo traveled through water, pressure sensors measured depth and adjusted the rudders to maintain the preset running depth. In theory, the system was reliable.

 In practice, water temperature variations, manufacturing tolerances, and mechanical wear caused depth control failures in 30% of Mark 8 torpedoes. Cold water increased density, making torpedoes run shallow. Warm water decreased density, making them run deep. The tropical waters of Surigal Strait registered 78° F on October 25th, 1944.

warm enough to affect torpedo buoyancy by two to three feet. Manufacturing variations added another layer of unpredictability. Each Mark 8 torpedo contained 2,827 individual parts machined to tolerances measured in thousandth of an inch. A hydrostatic valve spring compressed 0.

005 in too much would cause the torpedo to run 3 ft deeper than designed. A rudder hinge with 0.0003 in extra play would create a twoderee angle that sent the weapon diving. Serial number 11847 had both problems. Postwar analysis of similar torpedoes from manufacturing lot 237 revealed consistent depth control issues. The lot had been produced during a period when Newport Naval Torpedo Station was running three shifts to meet wartime demand.

 Quality control inspections were abbreviated. Acceptance testing was reduced from 12 test firings per lot to six. The torpedo that struck Abukuma ran at approximately 15 ft below the surface, 5 ft deeper than designed, deep enough to pass completely under the Japanese destroyer’s hull. Japanese destroyers of the Fubuki and Akatsuki classes drew 5 ft of water, even adding 2 ft for below waterline hull contours.

The destroyers presented 7 ft targets from keel to water line. A torpedo running at 15 ft would pass underneath with 8 ft of clearance, but Nagara class light cruisers drew 16 ft. Abukuma’s keel sat 16 ft below the water line when fully loaded. Her hull extended another 28 ft above water line to her main deck, a 44 ft vertical target.

 The 15 ft deep torpedo struck Abukuma’s hull 11 ft below the water line in the most vulnerable location possible directly beside the number one boiler room. If serial number 11847 had run at its designed depth of 10 ft, it would have struck the destroyer. The explosion would have damaged or sunk a 1500 ton destroyer.

 A valuable kill, but not a strategic impact. One destroyer, more or less, wouldn’t have affected Admiral Shima’s decision to retreat. Instead, the deep running torpedo missed the destroyer and hit a 5,000 ton cruiser. The hit crippled Admiral Shima’s flagship capability. Abukuma served as command ship for destroyer squadron 1, coordinating movements of four destroyers in the formation.

 When the cruiser fell out of formation, Admiral Shima lost his destroyer coordination platform. The subsequent collision between cruiser Nachi and cruiser Moami occurred partly because Abukuma wasn’t in position to relay course change orders to the formation. The torpedo’s defect had strategic consequences. A weapon that failed to perform as designed achieved better results than a weapon working correctly would have accomplished.

 The United States Navy had spent 6 years developing depth control systems for Mark 8 torpedoes. Engineers had tested hundreds of prototypes. The Bureau of Ordinance had invested millions of dollars in hydrostatic valves, pressure sensors, and control mechanisms. All of that engineering effort was defeated by manufacturing variations measuring thousandth of an inch.

 But those manufacturing variations saved PT 137. If Kovar’s torpedo had run at 10 ft and struck the destroyer, the explosion would have alerted every Japanese ship in the formation. Search lights would have found PT-137 within seconds. 5-in guns from four destroyers would have concentrated fire on one wooden boat. PT-137 displaced 56 tons.

 A single 5-in shell carried 70 lb of high explosive. Two or three hits would have sunk the PT boat. The deep running torpedo gave Kovar different results. The destroyer never knew it had been targeted. The explosion 900 yards behind the destroyer looked like a different PT boat’s attack.

 Japanese search lights swept in the wrong direction. PT-137 escaped because its torpedo missed the intended target. Kovar survived because his weapon malfunctioned. His crew lived because a hydrostatic valve spring was compressed 0.005 in too much at Newport Naval Torpedo Station in August 1944. 12 men owed their lives to a manufacturing defect.

 The United States Navy never corrected the Mark 8 torpedo’s depth control problems. By late 1944, the Bureau of Ordinance had shifted focus to the Mark13 aircraft torpedo and the Mark1 14 submarine torpedo. PT boat torpedoes received lower priority. Manufacturing lot 237 continued in service through the end of the war.

 Hundreds more Mark 8 torpedoes ran deep, missed their targets, or achieved unexpected hits. No one ever thanked the factory worker at Newport who compressed that spring 0.005 in too much. No one knew which worker it was. But that unknown error saved 12 American lives and sank a 5,000 ton cruiser. Sometimes the difference between success and failure measures thousandth of an inch.

 Lieutenant Junior Grade Isidor Michael Kovar left active duty in August 1945, two weeks after Japan surrendered. He returned to civilian life in the United States. No interviews, no memoirs, no publicity tours. The Navy Cross recipient who sank the largest warship ever credited to a PT boat disappeared from public record. While other PT boat commanders became famous, John F. Kennedy, John D.

 Balkley, Kovar remained unknown. The contrast was stark. Lieutenant Commander John Bowley received the Medal of Honor for evacuating General Douglas MacArthur from the Philippines in March 1942. He became a national hero. Hollywood made a movie about his exploits. Bowley gave speeches, attended ceremonies, and remained a public figure for decades.

Lieutenant Junior Grade John F. Kennedy commanded PT 109 when it was rammed by Japanese destroyer Amagiri in August 1943. Kennedy saved his crew by swimming for hours while towing a wounded sailor. He became president of the United States 19 years later. PT 109 became the most famous patrol torpedo boat in history.

But Kovar sank a cruiser, a 5,000 ton warship with a crew of 500, the most significant combat achievement by any PT boat commander in terms of tonnage destroyed. And history forgot him. Part of the reason was timing. Kovar’s action occurred during the battle of Lee Gulf, the largest naval battle in history.

Four separate engagements occurred simultaneously across 500 m of ocean. The battle off Samar, where escort carriers and destroyers fought Japanese battleships, dominated headlines. The sinking of one Japanese cruiser by a PT boat torpedo barely registered in the flood of battle reports. Part of the reason was the accidental nature of the hit.

 The Navy cross citation credited Kovar with extraordinary heroism under fire. It didn’t mention that his torpedo had missed the intended target. It didn’t explain that a manufacturing defect had caused the unexpected hit. Military citations avoid mentioning luck or accidents, focusing instead on courage and tactical skill. And part of the reason was Kovar himself.

 After the war, he chose obscurity. No book deals, no documentary interviews. He let Kennedy and Bowley have the spotlight while he returned to whatever civilian life he’d built. Before December 1941, the United States Navy decommissioned its last operational PT boat in 1946. The wooden vessels had served their purpose.

 Radar equipped destroyers and destroyer escorts could perform PT boat missions more effectively. Jet aircraft could attack enemy shipping faster than PT boats could reach targets. The era of wooden motor torpedo boats ended with World War II. Most PT boats were destroyed immediately after the Japanese surrender.

 The Navy burned them, sank them, or sold them as scrap lumber. Out of 326 Elco 80 ft boats built, fewer than 12 survived into the 21st century. Most survivors sit in museums, preserved as examples of wartime innovation and the courage of their crews. PT-137 was not among the survivors. The boat was scrapped in 1946 at Samar, Philippines.

The wooden hull was disassembled. The three Packard engines were removed and sent to depot maintenance facilities. The Mark1 18 torpedo tubes were salvaged for parts. Nothing remained of the boat that fired the most significant torpedo shot in PT boat history. No memorial exists for PT-137. No museum display commemorates the accidental hit that crippled Abukuma.

The National Museum of the Pacific War in Fredericksburg, Texas has PT boat exhibits, but PT 137 isn’t mentioned. The PT Boat Museum in Fall River, Massachusetts, preserves PT796 and PT617, but has no artifacts from PT37. The only physical evidence of PT37’s achievement is underwater. Abukuma’s wreck lies in 40 ft of water off Negros Island in the Philippines.

 Sport divers occasionally visit the site. The cruiser’s bow section, blown off by the torpedo magazine explosion, sits 200 yd from the stern section. The hull is heavily corroded. Tropical marine life has colonized the wreck. In another 50 years, the ship will be unrecognizable, but the story remains. A 24year-old officer commanded a blind PT boat through enemy controlled waters.

 He fired a defective torpedo at a destroyer. The torpedo missed. It ran deep. It struck a cruiser he didn’t know was there. The cruiser sank. 250 Japanese sailors died. The officer received the Navy Cross and disappeared into history. The mocked torpedo, the failed shot, destroyed 5,570 tons of Japanese steel.

 Not through superior engineering, not through tactical brilliance, through a manufacturing defect measuring 0.005 in. And that might be the most honest war story ever told. The Battle of Surau Strait changed naval warfare forever. It was the last time battleships would engage battleships in combat. Radar fire control, coordinated destroyer torpedo attacks, and aircraft carriers had made the battleship obsolete.

 The six American battleships that crossed the tea at Suruga Strait, West Virginia, Maryland, Mississippi, Tennessee, California, and Pennsylvania never fired their main batteries in combat again. Vice Admiral Shoji Nishimura went down with battleship Yamashiro. He was 54 years old. His decision to charge into Suruga Strait without waiting for Admiral Shima’s support force cost Japan two battleships, four destroyers, and over 4,000 lives.

 But Nishimura followed orders. The Imperial Japanese Navy’s plan for defending the Philippines required his sacrifice. Admiral Kiohide survived. His force retreated to Brunai, then to Japan. He commanded increasingly desperate operations as American forces closed on the home islands. After the war, Shima testified at war crimes tribunals, providing evidence about Japanese naval operations.

 He died in 1973 at age 76. Destroyer Ushio survived the entire war. The ship that rescued 283 survivors from Abukuma continued operations through August 1945. Usio was the only Japanese destroyer from the Pearl Harbor attack force, still afloat when Japan surrendered. The ship was scrapped in 1947. Abukuma had participated in the attack on Pearl Harbor on December 7th, 1941.

The cruiser served as flagship for Destroyer Squadron 1 in Vice Admiral Chuichi Nagumo’s carrier strike force. Abukuma screened the six carriers that launched 353 aircraft against the American Pacific Fleet. 3 years and 10 months later, an American torpedo sent her to the bottom. Lieutenant Junior Grade Isidor Michael Kovar earned the Navy Cross for extraordinary heroism at the Battle of Suragal Strait.

 He commanded PT-137 through enemy controlled waters without radar or radio. He closed to 900 yd of Japanese warships under star shell illumination. He launched a torpedo that the Navy had designed to run at 10 ft below the surface. Manufacturing variations at Newport Naval Torpedo Station caused serial number 11847 to run at 15 ft instead.

 The defect measured 0005 in in a compressed spring. That tiny error made the torpedo run 5 ft deeper than designed, deep enough to pass completely under the Japanese destroyer Kovar was aiming at. Deep enough to continue traveling until it struck light cruiser Abukuma 900 yd beyond. They mocked the Mark 8 torpedo, 30% failure rate, unpredictable depth control, weapons that porpused across the surface or dove to the ocean floor.

PT boat crews called them swimming slot machines because hitting anything was pure chance. But serial number 11847 didn’t fail. It ran exactly deep enough to miss a 1500 ton destroyer and hit a 5,570 ton cruiser. The explosion at 0335 destroyed Abukuma’s forward boiler room in seconds, killed 37 crew instantly, flooded two compartments, reduced speed from 36 knots to 10 knots, turned a combat ready flagship into a crippled wreck that would sink under B24 bombs 27 hours later.

 The failed torpedo destroyed the largest warship ever credited to an American PT boat. Not through superior engineering, not through tactical brilliance, through a manufacturing defect measuring thousands of an inch and 900 yards of blind luck. Kovar returned to civilian life after the war and disappeared from history. No book deals, no interviews, no memorial.

While John F. Kennedy became president and John Balkley became famous, Isidor Kovar remained unknown. The officer who sank a 5,000 ton cruiser was forgotten, while officers who sank nothing became celebrities. PT-137 was scrapped in 1946. No museum preserved the boat. No artifacts survived.

 The only evidence of its greatest moment lies underwater off Negros Island where Abukuma’s broken hole rests in 40 ft of water. Sometimes the mocked weapon becomes the most effective weapon. Sometimes the failed shot becomes the killing blow. Sometimes the forgotten heroes change history while everyone watches someone else. If this story moved you the way it moved us, do me a favor, hit that like button.

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