Kennedy's actions in saving his surviving crew after PT-109 was rammed and sunk by a Japanese destroyer earned him several commendations and made him a war hero.

The seventh MTB of the PT-103 class, her keel was laid 4 March 1942, she was launched on 20 June, and delivered to the Navy on 10 July 1942 to be fitted out in the New York Naval Shipyard in Brooklyn.

They had strong wooden hulls, constructed of two layers of 1-inch (2.5 cm) mahogany planking, excellent for speed and reasonably adequate for seakeeping, but providing limited protection in combat.

PT-109 was powered by three 12-cylinder 1,500 horsepower (1,100 kW) Packard 4M-2500 marinized aero gasoline engines (one per propeller shaft), with a designed top speed of 41 knots (76 km/h; 47 mph).

The center engine was mounted forward of the outboard pair in a conventional orientation, with power transmitted directly from its output end to an extended propeller shaft.

[4] In contrast, the Japanese Type 93 destroyer torpedo, later called the "Long Lance", was faster at 45 knots (83 km/h; 52 mph), had an accurate range of 20,000 yards (18,000 m), was far more powerful with 1,000 pounds (450 kg) of high explosives, and unlike the Mark 8, its detonator usually worked when it hit a target.

Seeking to augment the boat's firepower (given the inaccuracy and unreliability of its torpedoes), the day before her final mission, Kennedy had the PT-109's crew lash a U.S. Army 37 mm antitank gun he had bartered for to the foredeck, replacing a small, two-man life raft.

Kennedy's father persuaded his old friend Captain Allan Goodrich Kirk, USN, head of the Office of Naval Intelligence, to let a private Boston physician certify his son's good health.

Although PT-109 was less than a year old, it had seen heavy combat service since its arrival in the Pacific, and considerable repairs were required on the boat; leading by example, Kennedy pitched in to help the crew get his vessel seaworthy.

The Navy men stationed there also contended with cockroaches, rats, foot diseases, ear fungus, and mild malnutrition from the monotonous and mostly canned food.

On his first desk assignment with the Navy after his return to the States, Kennedy suffered from the aftereffects of malaria, colitis, and chronic back pain, all caused or aggravated by his experiences in combat or during his stay at the Rendova base.

[17] The following men were aboard on PT-109's last mission: At the end of July 1943, intelligence reports were received and decoded by Naval authorities at Kennedy's PT base on Rendova Island indicating that five enemy destroyers were scheduled to run the night of 1–2 August.

A few other PTs, including the leader of Division A to the south of Kennedy, intercepted the destroyers on their southbound route close to Kolombangara, but were unable to hit any with torpedoes.

Late in the night, PT-109 and two accompanying PTs became the last to sight the Japanese destroyers returning on their northern route to Rabaul, New Britain, New Guinea, after they had completed dropping their supplies and troops at 1:45 a.m. on the southern tip of Kolombangara.

[33] Amagiri was traveling at a relatively high speed of between 23 and 40 knots (43 and 74 km/h; 26 and 46 mph) in order to reach harbor by dawn, when Allied air patrols were likely to appear.

Amagiri's captain, Lieutenant Commander Kohei Hanami, later claimed that he intentionally turned hard to starboard and deliberately rammed PT-109, which was traveling at a steady pace towards them.

Seamen Andrew Jackson Kirksey and Harold William Marney were killed instantly, and two other members of the crew were badly injured and burned when they were thrown into the flaming sea surrounding the boat.

[42] Kennedy was able to rescue MM1 Patrick McMahon, the crew member with the most severe wounds, which included burns that covered 70 percent of his body, and brought him to the floating bow.

[43] On instructions from Kennedy, the eleven survivors thrown from PT-109 regrouped and, hoping for rescue, clung to PT-109's bow section for 12 hours as it drifted slowly south.

The explosion and resulting fireball on the early morning of 2 August was spotted by Evans, who manned a secret observation post at the top of the Mount Veve volcano on Kolombangara; more than 10,000 Japanese troops were garrisoned below on the southeast portion.

[34] Evans had been the first to dispatch islander scouts, Gasa and Kumana, in a dugout canoe late on 5 August, to look for possible survivors after decoding radio broadcasts that the explosion he had witnessed was PT-109.

They had eaten only a few ripe coconuts, rainwater caught on leaves, and small amounts of fresh water and Japanese cookies Kennedy had taken from Naru Island.

After finally receiving Evans' radioed message of the discovery of the 109 crew, and facing overwhelming evidence that Kennedy had returned from the dead, he cautiously consented to risk two PTs to rescue them.

To avoid making a wake, Liebenow traveled at 10–15 knots (19–28 km/h; 12–17 mph), muffled his engines, and zigzagged to prevent being tracked by planes or shore batteries.

With Kennedy aboard, PT-157 rescued the weak and hungry PT-109 crew members on Olasana Island in the early morning of 8 August, after dispatching rowboats to pick them up.

The 157 then motored the full crew and the coastwatcher scouts forty miles (64 km) back to the Rendova PT base where they could begin to receive medical attention.

Kumana and Gasa made it to the airport in Honiara, but were turned back by Solomon Island officials on the grounds that their appearance and pidgin English would be an embarrassment.

[73] In 2007, the commanding officer of USS Peleliu, Captain Ed Rhoades, presented Kumana with gifts, including an American flag, for his actions more than 60 years earlier.

Nine years after the sinking of PT-109, U.S. Representative John Kennedy, engaged in a race for the Senate, instructed his staff to locate Kohei Hanami, Commander of the Amagiri, the Japanese destroyer that had run down the 109.

When they found Captain Hanami, Kennedy wrote him a heartfelt letter on 15 September 1952, with wishes of good fortune for him and for long-term peace between Japan and the United States.