4. PT 109 departed on its last mission on August 1, 1943
On August 1, 1943, PT 109 was one of fifteen boats which departed Rendova, informed by American code breakers of Japanese Naval activity. Kennedy was in command of 109, which carried a crew of ten enlisted and, in addition to Kennedy, two commissioned officers. One, Ensign George Ross – known as Barney – was an observer. Ross had lost his boat in action previously. Their orders were to prevent the Japanese from reinforcing and resupplying the garrison on the island of New Georgia. Codebreakers had provided the information that five Japanese destroyers were planning to run through a body of water known as Blackett Strait.
The PT boats were to engage the enemy destroyers in the dark of night, surprising them with a torpedo barrage and retiring at high speed. The fifteen boats were the largest coordinated PT boat assault of the war. Kennedy and PT 109 were assigned to a group of four boats led by PT 159. In the attack, PT 159 advanced and launched a torpedo attack without informing Kennedy of its actions. In the dark, and in radio silence, PT 109 waited while another boat, PT 157 launched a second supportive attack. The American boats launched 6 torpedoes, none of which found their targets, before retiring behind a smoke screen. PT 109 waited in the Blackett Strait, its engines idling, as the supporting boats sped away and the Japanese flotilla bore down upon its position.