America Built a Torpedo That Finally Worked, and Japan's Merchant Fleet Disappeared

America Built a Torpedo That Finally Worked, and Japan's Merchant Fleet Disappeared For nearly three years of the Pacific War, America’s submarines were fighting with a weapon that often failed at the worst possible moment. The Mark 14 torpedo ran too deep, exploded before reaching its target, or struck Japanese ships and failed to detonate. While U.S. submarine commanders kept reporting the same problems, the Bureau of Ordnance continued defending the weapon. Then everything changed. After independent testing at Pearl Harbor exposed the Mark 14’s depth error and engineers finally corrected its contact exploder, American submarines entered late 1943 with torpedoes that could actually do what they had been designed to do. What followed was devastating for Japan. This WWII documentary explores: • Why the Mark 14 torpedo failed for so long • How its depth-control problem was finally proven • Why the Mark 6 exploder failed on direct hits • Admiral Charles Lockwood’s role in fixing the weapon • The USS Tinosa and Tonan Maru torpedo failure • How the Mark 18 electric torpedo changed submarine attacks • Dudley Morton’s aggressive submarine tactics • Why Japan’s merchant fleet was so vulnerable • How American submarines destroyed Japanese tankers and cargo ships • Why oil shortages crippled Japan’s aircraft training and surface fleet • How the submarine war helped isolate Japan from the resources it had gone to war to capture DISCLAIMER This video is created for historical, documentary, educational, and informational purposes. Combat, military casualties, ship sinkings, weapons, and wartime losses are discussed strictly within their historical context. The video does not glorify war, violence, or human suffering. Statistics, tonnage figures, casualty estimates, and operational details are based on the historical sources and records referenced in the script. Exact figures may vary between official reports, postwar assessments, and later historical research. Some archival-style or AI-assisted visuals may be used for illustration and may not depict the exact vessel, person, location, or moment described in the narration. #ww2 #worldwarii #pacificwar #usnavy #submarinewarfare #mark14 #Mark18 #