"After being on the seabed for over a century, the submarine appears to be in a remarkable condition with the conning tower present and the bows partially buried."
Mark Dunkley, Historic England
Energy companies ScottishPower and Vattenfall, which were carrying out seabed surveys in order to plan the construction of proposed offshore wind farms, first discovered the uncharted submarine wreck in 2012.
It was initially thought it could be the Dutch Navy’s final missing World War Two submarine – but divers have now confirmed it is the missing U-31 submarine.
Mark Dunkley, marine archaeologist at Historic England, said: "SM U-31 was commissioned into the Imperial German Navy in September 1914. On 13th January 1915, the U-31 slipped its mooring and sailed north-west from Wilhelmshaven for a routine patrol and disappeared.
"It is thought that U-31 had struck a mine off England’s east coast and sank with the loss of its entire complement of 4 officers, 31 men.
"After being on the seabed for over a century, the submarine appears to be in a remarkable condition with the conning tower present and the bows partially buried.
"Relatives and descendants of those lost in the U-31 may now take some comfort in knowing the final resting place of the crew and the discovery serves as a poignant reminder of all those lost at sea, on land and in the air during the First World War."
The wreck will remain in its final resting place, which is now an official military maritime grave, and any future wind farm developments in the area will be designed so as not to disturb the wreck.
Charlie Jordan, of ScottishPower Renewables, said: "The scanning team were expecting to see wrecks, but such a discovery was quite a surprise and has been extremely interesting.
"Unravelling the whole story behind the submarine has been fascinating and it’s heartening to know that the discovery will provide closure to relatives and descendants of the submariners lost who may have always wondered what had happened to their loved ones."
The exact location of the wreck
By the summer of 1921, the Baltimore-built USS Conestoga and the tugboat's 56 crew members had been missing for months, vanished into the Pacific Ocean.
For three months, in what was the Navy's largest sea-and-air search to date, aircraft and destroyers combed more than 300,000 square miles of sea around Hawaii. Urgent letters poured in from the crew's families.
"I have reason to believe the crew is still alive," wrote Roland Williams of Chicago, the father of a gunner's mate, to the Navy. He'd heard rumors of a mutiny. Sailors "turned Bolshevik," he wrote, "... and had headed for the golden fields of Siberia."
While the mystery gripped the nation, no sign of the steel tugboat built at Sparrows Point showed up and the Navy declared it lost at sea with all hands in June 1921.
Then 88 years passed. Routine mapping of the ocean floor in 2009 found something sunk in a marine sanctuary beyond the mouth of San Francisco Bay. In time, the find about 190 feet deep would lead to a three-year quest to identify the wreckage.
On Wednesday, the research team announced it had solved the mystery of the Conestoga — at least what happened to it, if not how. Descendants of the sailors finally got their answers at a ceremony in Washington.
"Today is the story less so of the Conestoga, than of the 56 men and families they left behind," said James Delgado, the director of maritime heritage for the National Oceanic and Atmospheric Administration. "You have been found. Your story will be told."
The Conestoga was somewhere no one expected: within sight of the California coast.
A sea tug launched
Amid cheers as a champagne bottle shattered against its bow, the 170-foot Conestoga was christened at the Sparrows Point shipyard. It then slid down the rails and into the Patapsco River. It was November 1903.
The steel tug weighed 617 tons with twin boilers to make steam and 1,000 horsepower. Its pilot house was fitted with brass and hardwood.
Through the next decade, the tug towed coal barges for the Philadelphia & Reading Railroad Co. to New York, Boston and Rhode Island from Philadelphia.
In September 1917, the Navy bought the tug for $315,000. The U.S. had entered World War I and the Conestoga was commissioned as a minesweeper. A three-inch gun was mounted on its deck.
Soon the steel tug was escorting Navy convoys to Bermuda and the Azores islands deep in the Atlantic Ocean. After the war, the tug was assigned harbor duty in Norfolk, Va., but later transferred to Pacific service.
The commanding officer was Lt. Ernest Larkin Jones, often photographed chewing a cigar. A former enlisted sailor, he grew up in landlocked Walnut, Kan., reading stories of the sea.
On March 25, 1921, he took the tug from San Francisco Bay, leaving behind his wife and 3-year-old daughter, heading to Pearl Harbor, Hawaii, and ultimately American Samoa.
"She could not remember him and that saddened her. She tried real hard, but being 3 when he died, she just couldn't," said Diane Gollnitz, of Lutherville, Jones' granddaughter.
Her mother, Paula, died at age 76 in the 1990s having never known her father.
"All we do with a father, all he teaches us, the memories and the fun times and discipline — and she didn't have that. It was just a void," Gollnitz said.
Passage from San Francisco to Pearl Harbor was supposed to take about two weeks. But the Conestogahadn't arrived by April 5, 1921. So the Navy mounted its search. Crews scoured the waters from Hawaii to the Mexican coast. They found no wreckage.
"The boat was stranded on Georgia Island. S.O.S. Quick ... crew facing starvation," Clara Schaffer, a professed psychic in Los Angeles, wrote the Navy, according to letters held by the National Archives.
"My husband, H.H. Reinbold, was aboard and I am anxious to learn if there is still hope for his safety," wrote Anne Reinbold of Norfolk, Va.
John Liisberg of Oregon, the father of a crewman, wrote, "Pray give us full publicity in the cause of this most terrible tragedy."
It was the summer of 1921 and there was Prohibition in America, Charlie Chaplin on the screens and Babe Ruth on the Yankees. And three weeks after the inauguration of President Warren G. Harding came another historical note. The USS Conestoga was declared lost.
Sunk within sight
Teeming with seals and seabirds, the rocky Farallon Islands rise about 30 miles from the mouth of San Francisco Bay in shark-infested waters.
NOAA researchers were mapping the Greater Farallones National Marine Sanctuary in August 2009 when their sonar detected something southeast of the islands, an unknown 170-foot structure lying on the seafloor. Three years passed before the news reached Robert Schwemmer, the NOAA's West Coast Regional Maritime Heritage coordinator.
The structure matched no known shipwreck off California. On the first research trip in September 2014, tethered robots plunged down to the wreckage. Their cameras captured a steel hull colonized with sea anemones, twin boilers, steam pistons, a towing winch.
"This was just a really large vessel," Schwemmer said.
He turned to old newspaper articles and read an account of the exhaustive three-month search around Hawaii for the Conestoga. He found the tug's building specifications online. The dimensions all matched the Maryland Steel Co.-built vessel, but there was no sign of the three-inch gun mounted to the deck.
Over and over, Schwemmer played the video footage. One day, he recognized a gun mount on the deck, but the gun appeared to have fallen into the hull.
"It doesn't get much better than that in shipwreck analysis," Delgado said. "It is literally the smoking gun."
They found more: letters "t" and "o" on the fantail.
"We were rewriting history," Schwemmer said. "You look at the newspaper accounts, it's rumor after rumor. Little did they know, it was 2,000 miles from where it was presumed lost."
Soon they sent letters to descendants of the sailors.
"It's so overwhelming," Gollnitz said. "The only mystery we ever had in our family has been solved."
Further research found record of a gale, winds nearly 48 mph, soon after the Conestoga departed. The team suspects the tug was taking water and veered for the shelter of the islands. Fifty-six sailors are believed to be entombed deep in the tug, and the wreck will remain undisturbed.
"We have one of the greatest maritime mysteries and now we can protect it as a military grave site." Schwemmer said.
In October, the research team returned to the wreckage. There was another dive and then the crew paused in silence.
On a gray, choppy morning, the research boat circled the site and the crew cast white rose petals in the wake, forming a wreath above the shipwreck.
Baltimore Sun researcher Paul McCardell contributed to this article.