A 312-foot Gato-class submarine navigated an uncharted enemy harbor using a page torn from a cheap geography atlas a crewman bought in Australia. This episode follows the USS Wahoo from her cautious, frustrating first two patrols under Marvin Kennedy, where targets like a carrier and an unescorted midget-sub tender slipped away, to the arrival of Dudley Mush Morton, who told the crew the boat was expendable and gave anyone who wanted out 30 minutes to leave. No one did.

We cover the Wewak harbor attack and the point-blank torpedo that broke the destroyer Harusame’s back, the deeply contested Buyo Maru incident and the discovery that many of those in the water were Indian prisoners of war, the record-breaking patrols in the shallow Yellow Sea where the crew fought with deck guns and Marine-donated Molotov cocktails, and the Mark 14 torpedo failures that left ten shots wasted in the Sea of Japan. Morton’s insistence on a seventh patrol with new Mark 18 electric torpedoes sank the Konron Maru, carrying two Japanese legislators, and triggered the hunt that ended the Wahoo in La Perouse Strait in October 1943. Her wreck was found in 2006.

• What diesel-electric really meant: a surface ship that could occasionally submerge
• How prewar caution doctrine wasted the Wahoo’s first patrols
• Morton’s expendable speech and the psychology of a volunteer crew
• Why 120-foot water in the Yellow Sea was both a death trap and an opportunity
• The Mark 14 exploder scandal and how it drove the boat’s fatal final patrol