On August 4, 1943, future president John F. Kennedy was commanding a motor-torpedo boat in the South Pacific when his boat collided with a Japanese destroyer, the Amagiri. The massive destroyer slammed broadside into the much smaller wooden boat cutting the PT 109 in two in ten seconds. Kennedy and ten of his sailors survived the ramming, and the young lieutenant rallied his men for a long swim to a nearby island. After resting there, Kennedy then undertook two subsequent long swims to find help, leading to the rescue of his crew.
After convalescing, Kennedy returned to combat, commanding the PT-59, and saving numerous Marine Raiders during an amphibious extraction from Choiseul Island during the Solomon Islands campaign. You can read a full account of Kennedy’s World War II leadership and service here.