USS PT-109, an 80-foot ELCO type motor torpedo boat, was placed in service in July 1942 as a unit of Motor Torpedo Boat Squadron FIVE. She was shipped to the Pacific shortly thereafter and in September 1942 was transferred to Motor Torpedo Boat Squadron TWO for service in the Solomon Islands during the ongoing Guadalcanal Campaign. During the last months of 1942 and the first part of 1943, PT-109 was employed on patrols in the waters adjacent to Guadalcanal, as part of an effort to prevent the Japanese from reinforcing their troops on the island.

After the Japanese evacuated Guadalcanal in February 1943, PT-109 remained in the Solomons. Following the seizure of Rendova Island, near New Georgia, she was based there with other PT boats, charged with interdicting enemy shipping during the fight to capture New Georgia.

While patrolling in Blackett Strait, on the southern side of Kolombangara Island, during the early hours of 2 August 1943, PT-109 was rammed by the Japanese destroyer Amagiri, cutting away the PT boat's starboard side and leaving her completely disabled. As she gradually sank during the day her eleven survivors abandoned ship to swim to an island some miles away. These men, led by their Commanding Officer, Lieutenant (Junior Grade) John F. Kennedy, had many adventures during the next week. With the aid of a Coastwatcher and local residents, PT-109's men were finally returned to the Rendova PT base on 8 August.