The future president in command of PT-109 left his base at 18:30 the first of August. His triple screw 80 ft Elco patrol boat was topped off with fuel and loaded for bear. She has four machine guns a new forward mounted 37 MM tank gun, and four loaded torpedo tubes. 14 PT boats total were in the squadron on a mission that night to intercept Japanese ships in the Blackett Strait. The group divided into four squadrons, with PT-109 patrolling near Makuti Island.
On August 2, around 02:30 Kennedy heard cannon fire and thought it was from land and idled and muffled his engines to listen and reduce his wake. With poor visibility the Japanese destroyer Amagiri was able to vector in on PT 109, her captain intentionally steered to run down PT- 109. With only seconds to react JFK tried to steer the 109 to starboard to fire the 37 mm deck gun, but PT 109 was cut in half by the Amagiri. PT-109 and her fuel caught fire, two of her crew were lost and never seen again. Eleven survived by clinging to the wreckage, including a badly burned man. Around 14:00 Lt. Kennedy took the burned McMahon in tow and set out swimming for land, a small coral island with 6 palm trees.
They made the island and for a couple of nights Kennedy swam out into the shipping lanes to try to signal friendy shipping. He did all this with a ruptured disk in his back caused by the collision. Then JFK swam to a neighboring island were he meet two natives in a canoe. Kennedy scratched this message on the coconut: “Nauru Isl commander / native knows posit / he can pilot / 11 alive need small boat / Kennedy.” Soon another PT boat was sent to rescue Kennedy and his crew.
Not long after he was rescued Kennedy led what some called a suicide day light mission to evacuate Marines from the Japanese-held Choiseul Island. He took on the mission knowing he had only enough fuel to get there and half way back. The mission was a success. His boat loaded with the marine ran out of fuel but another PT boat was able to meet him and towed them back to base.