On May 23, 1939, the brand-new submarine USS Squalus vanished beneath the waves off the New Hampshire coast during a routine test dive.

What followed was one of the most daring and dramatic rescues in naval history. Thirty-three men were trapped on the ocean floor, their lives hanging by a thread.

In this episode of Dave Does History, we dive into the harrowing story of disaster, heroism, innovation, and redemption.

From the failed valve that doomed the boat to the groundbreaking rescue that saved the survivors, this is the unforgettable tale of the Squalus—and her resurrection as the USS Sailfish.