USS Tinosa fired 15 torpedoes at Tonan Maru No. 3.

Only two exploded.

The problem wasn't the submarine's aim. It was the U.S. Navy's Mark 14 torpedo - and a chain of hidden defects that American submariners were forced to uncover during combat.

This documentary follows the Mark 14 crisis from torpedoes running too deep, to premature magnetic detonations, to a contact exploder that could fail during an almost perfect direct hit.

Each solution exposed another problem.

The story follows USS Tinosa, Tonan Maru No. 3, Rear Admiral Charles Lockwood, Admiral Chester Nimitz, the Mark 6 exploder, and the tests that gradually revealed what prewar development had missed.

By the time the Mark 14 became dependable, the Pacific submarine force had spent months discovering its weaknesses under real combat conditions.

CHAPTERS

00:00 - USS Tinosa vs. Tonan Maru No. 3
01:24 - A Pattern of Torpedo Failures
02:07 - The Mark 14 and Mark 6 Exploder
03:40 - Running Too Deep
05:17 - Lockwood Tests the Problem
06:20 - The Magnetic Exploder
07:45 - Nimitz Makes the Decision
08:14 - Tinosa Returns
09:28 - The Torpedo Brought Back as Evidence
10:14 - The Contact Exploder
10:50 - Why a Perfect Hit Could Fail
12:22 - Fixing the Mark 14
13:09 - Multiple Defects, One Weapon
14:16 - The Final Lesson

SOURCES & FURTHER READING

Naval History and Heritage Command - H-Gram 008: Torpedo Versus Torpedo

U.S. Naval Undersea Museum - MK 14 Torpedo

Naval History and Heritage Command - USS Tinosa (SS-283) ship history

Submarine Force Library & Museum - Tinosa's Terrible Torpedoes

U.S. Navy / National Archives archival material and technical documentation

Archival photographs and footage used in this documentary primarily come from public-domain collections of the U.S. Navy, National Archives, Naval History and Heritage Command, Australian War Memorial and Wikimedia Commons.

Some explanatory graphics and the background music were created with generative AI.

#WWII #NavalHistory #SubmarineHistory