Historians say wreck probably PT-109

Kennedy was a lieutenant junior grade in the U.S. Navy when his PT-109 was hit by a Japanese destroyer in August 1943.

WASHINGTON (CNN) -- The wreckage of a navy vessel found off the Solomon Islands in the South Pacific is probably John F. Kennedy's World War II patrol boat, PT-109, a panel of naval historians said Wednesday.

The National Geographic Society commissioned an expedition in May to search for the wreck, led by Robert Ballard, best known for his discovery of the Titanic in 1985.

At the time, Ballard said his findings were promising but inconclusive, pending review by naval experts.

Ballard said the site, under 1,200 feet of water, is very difficult to maneuver with large, active sand waves and a very strong current.

"Imagine that you are on the top of a big sand dune in the Sahara Desert, and you're looking down from the top of the dune down into the trough between sand dunes. Down at the very bottom you see a piece of the boat sticking out of it," Ballard said.

EXTRA INFORMATION Click here for a map and details of the PT-109  John F. Kennedy's World War II naval career  (Naval Historical Center)   CNN NewsPass VIDEO The man responsible for finding the Titanic believes he has found the remnants of former U.S. president John F. Kennedy's World War II patrol boat, PT-109 (July 11) Play video

"The boat is mostly buried. The port side aft is what's sticking out, and the most exposed and highest part of the PT boat is the aft torpedo launcher with a torpedo still inside of it.

"Inboard from that, you have some fittings from the deck sticking up, and beneath the torpedo launcher are the mahogany blocks on which it sat," Ballard added.

A team of scholars at the Naval Historical Center in Washington reviewed imagery of the wreck site and verified the finding of several key items -- in particular, a Mark 18 torpedo tube and a Mark 8 Mod 3 torpedo used by the U.S. Navy to outfit PT-type boats.

A check of Navy records indicated PT-109 was the only patrol vessel lost in that location, leading naval experts to conclude the wreckage is most likely that of PT-109.

After the battles at Midway and Guadalcanal, U.S. naval forces moved up "The Slot," the deep channel amid the islands. Blackett Strait near Gizo Island, part of the Solomon Islands in the South Pacific, was briefly an active warfront.

Underwater image of a torpedo believed to be from PT-109.

Lt. j.g. John F. Kennedy assumed command of PT-109 on April 24, 1943. In the wee hours of August 2, 1943, the Japanese destroyer Amagiri rammed the boat, which sank in the strait near Gizo.

Two of the 13 sailors on board PT-109 lost their lives in the engagement with Japanese destroyers that night.

The survivors swam to nearby Plum Pudding Island -- now Kennedy Island -- and were rescued six days later by natives and Australian forces.

None of the survivors is alive today. Kennedy, who later became the 35th president of the United States, was assassinated November 22, 1963.

Ballard and his team searched a 5 mile by 7 mile grid with sonar technology to locate the wreck site. Unmanned vehicles with high-definition video cameras went below to take a look. The wreckage, resting on a sandy bottom, will not be disturbed.

"Historically, we do not disturb these sites. Our philosophy is to find them and document them," says Ballard.

Part of the Solomon Islands near where the wreckage was found

"Although most of the PT boat is buried, we have an understanding with the Kennedy family as well as others who lost loved ones -- there were two people lost on the boat -- that we will not disturb the site."

Ballard, National Geographic's explorer-in-residence, has also participated in shipwreck expeditions of the German battleship Bismarck and the American aircraft carrier Yorktown. He is also the president of the Institute for Exploration in Mystic, Connecticut.