The underwater sonar images of a black shape against a grainy, monochrome background are the biggest clues in more than 60 years to the fate of a United States submarine lost during World War II.
For decades, relatives of the USS Grunion‘s 70 lost crewmen had no information beyond fragmented US navy records, and a few rumours, about where and why the sub went down near the obscure islands at the tip of Alaska’s Aleutian chain.
They knew the Grunion had sunk two Japanese submarine chasers and heavily damaged a third in July 1942 near Kiska, one of two Aleutian islands occupied by the Japanese. They knew her last official radio message to the sub base at Dutch Harbour, on July 30 1942, described heavy enemy activity. They knew Dutch Harbour responded with an order to return to the base, but they don’t know if Grunion ever received it.
Until a few years ago, the clues were too sparse to justify a search, said Bruce Abele, whose father, Mannert Abele, was the Grunion‘s commander.
”We really didn’t do anything about it because there was nothing, no information,” Abele said. ”What were we going to do?”
Four years ago, a man who had heard about the Grunion‘s disappearance e-mailed links to several Grunion websites to Bruce Abele, who lives in Newton, Massachusetts.
One site held an entirely new clue, a note from a Japanese model ship builder who said he thought he knew what had happened to the Grunion.
Abele’s youngest brother, John, contacted the man, who translated and sent him a report written in the 1960s by a Japanese military officer who served in the Aleutians.
It described a confrontation between a US submarine and the officer’s freighter, the Kano Maru, on July 31 1942, about 16km north-east of Kiska.
The sub dispatched several torpedoes. All but one bounced off the boat without exploding, or missed, the officer wrote, although the hit knocked out his engines and communications. He said he returned fire and believed he had sunk the sub.
The Abele brothers — Bruce, Brad and John — began investigating the identity of the sub in the Kano Maru officer’s report.
They hired a marine survey firm, Seattle-based Williamson and Associates, for an expedition in August to Kiska.
Williamson at first told the Abeles that surveying the tip of the Aleutian archipelago would be too expensive, Bruce Abele said, but the firm eventually agreed to send sonar technicians and equipment aboard a Bering Sea crab boat to the frigid waters licking the base of Kiska volcano.
The Aquila, carrying more than a dozen crew members and sonar surveyors, set out on August 2, said Pete Lowney, a family friend.
For more than two weeks, the Aquila carefully towed a sonar cable inside a 614-square-kilometre grid.
Sonar images can deceive even those who interpret them for a living. Elongated boulders look like submarines; outcrops resemble ship’s prows.
”It’s a rocky seascape,” said Art Wright, survey manager for Williamson. ”We went over the areas several times to differentiate between rock and ship and look at things from three to four different aspects.”
In mid-August, the sonar picked up a 88m-long object wedged into a terrace on the steep underwater slope of the volcano.
The Grunion, however, was 94m long. The Williamson team believes the bow may have plowed beneath a mat of thick sediment, hence the apparent shortage. Skid marks show the vessel slid to rest about 1 000m from the surface, Wright said.
Wright is 95% sure the shadowy images are those of the vanished sub. The Grunion is the only known sunken vessel in the area and the sonar captured the distinct outline of a submarine conning tower, he said.
”If our target is not the Grunion, where is she?” Wright said.
But the Abeles remain circumspect about the find.
”Although it’s very encouraging at the moment, it’s dangerous to say, ‘Absolutely, we have it,”’ Bruce Abele said in August during a brief stop in Anchorage.
But they have enough faith in the wreck to send out a second expedition next summer, this time with a remote-controlled underwater camera to identify the vessel and try to reconstruct her sinking. – Sapa-AP