SAN FRANCISCO, March 23 (UPI) -- Nearly a century after it disappeared literally without a trace, the USS Conestoga has finally been located off the Northern California coast -- solving perhaps the biggest maritime mystery in the history of the U.S. Navy, officials said Wednesday.
The remains of the tugboat, which vanished almost 95 years ago, were first discovered in 2009 by explorers at the National Oceanic and Atmospheric Administration -- but it took nearly seven years for shipwreck experts to confirm it is indeed the World War I duty ship.
In 2014, NOAA launched a two-year investigation of historic shipwrecks near the Greater Farallones sanctuary and Golden Gate National Recreation Area. By October 2015, the agency had confirmed the identification and location of the long lost Conestoga.
"After nearly a century of ambiguity and a profound sense of loss, the Conestoga's disappearance no longer is a mystery," deputy NOAA administrator Manson Brown said Wednesday. "We hope that this discovery brings the families of its lost crew some measure of closure and we look forward to working with the Navy to protect this historic shipwreck and honor the crew who paid the ultimate price for their service to the country."
The Conestoga, commissioned by the Navy in 1917, was last seen steaming for Pearl Harbor, Hawaii, on the afternoon of March 25, 1921. About a half hour after passing beneath the Golden Gate Bridge in San Francisco, the crew of the Conestoga encountered trouble.
The ship and its 56 crew began to be tossed around by large waves and gale-force winds after passing Point Bonita, on the edge of San Francisco, and were never heard from again. The U.S. Navy immediately began searching for the vessel -- which was headed for American Samoa, by way of Pearl Harbor -- when it didn't arrive on April 5 as scheduled.
The boat's disappearance made headlines around the world and prompted the largest air and sea search in history, up to that time -- surpassed in scope only by the search for American aviator Amelia Earhart and navigator Fred Noonan 16 years later.
Researchers believe the crew of the Conestoga was trying to steer toward a protected cove on Southeast Farallon Island, to get away from the rough waters, when it sank and settled beneath 200 feet of water.
"As Conestoga was in trouble and filling with water, it seemingly was the only choice to make," the NOAA said in a report on the vessel's find. "This would have been a desperate act, as the approach is difficult and the area was the setting for five shipwrecks between 1858 and 1907."
Based on various projections, the Navy initially believed the Conestoga would be found further south, near Baja, Calif., and the Mexican coast -- particularly after a lifeboat with the letter "C" was found near that region a short time after the tug's disappearance. It was later determined that lifeboat had not come from the Conestoga.
After a three-month search, the Navy declared the Conestoga and her crew lost at sea. It was the last U.S. military vessel to disappear in peacetime, the Navy said.
Nothing further would become known about the ship's fate for another 88 years, until the remains were found in the Greater Farallones National Marine Sanctuary by explorers charting shipwrecks in the Pacific.
"Thanks to modern science and to cooperation between agencies, the fate of Conestoga is no longer a mystery," Assistant Secretary of the Navy for Energy, Installations and Environment Dennis McGinn said Wednesday. "In remembering the loss of the Conestoga, we pay tribute to her crew and their families, and remember that, even in peacetime, the sea is an unforgiving environment."
Originally built to tow coal barges for the civilian Philadelphia and Reading Railroad Co., the Navy purchased the Conestoga in 1917 for use in World War I -- mainly for convoy and other services on the Atlantic coast. It was later reassigned to harbor duties in Norfolk, Va., in 1919 before it was ordered to service in Tutuila, American Samoa. The Conestoga had just left San Francisco's Mare Island Naval Shipyard and was on its way to its new post when it vanished.
According to the NOAA, a garbled radio transmission from the ship said it was "battling a storm and that the barge she was towing had been torn adrift by heavy seas."
Explorers said the ship sank, basically, in one piece, but has turned into a conglomerate of marine life after nearly 100 years at the bottom of the Pacific.
No human remains have been sighted in any of the NOAA's dives, officials said. The shipwreck is protected by the Sunken Military Craft Act of 2004, which prohibits any disturbance at the site.