In the late 1800s, the invention of the self-propelled torpedo incited a revolution in ship design. Navies needed new vessels to fire them and to defend against them. Enter torpedo boats--fast, lightweight ships that would play a big role in both World Wars. The very first one was constructed in Chiswick on the River Thames. Although pioneered by the British, it was the Germans that built some of the deadliest torpedo boats, known as Schnellboots. They showed their capabilities when a group of S-Boats stumbled on a D-Day rehearsal off the coast of Dorset - over 700 men were killed. The MTB 102 was the smallest vessel to ever serve as a Royal Navy flagship. John F. Kennedy first made headline news in 1943 as skipper of a motor torpedo boat, the PT-109, when he and his crew were shipwrecked in the Pacific. We tell the story of their rescue.