For 95 years, the gravesite of the USS Conestoga and her 56 crewmembers remained a mystery. Thought to have been somewhere in the vast Pacific off Mexico or Hawaii, the wreck of the oceangoing Navy tug was found and identified recently less than a day’s voyage from San Francisco, where she had set out on a 4,800-mile passage to her new duty station in American Samoa on March 25, 1921.

“I’ve never in my career had something like this happen: Find something where nobody thought it would be, solve a 95-year-old mystery and bring closure to the families of a ship’s crew,” says Jim Delgado, director of NOAA’s Maritime Heritage Program and co-leader of the NOAA-Navy team that identified the wreck of the 170-foot steel-hulled tug.

The Conestoga was found on the seabed in 189 feet of water, three miles off Southeast Farallon Island and 30 miles southwest of the Golden Gate. NOAA and the Navy announced their find at a ceremony this past spring to honor Conestoga’s crew and gather their families at the U.S. Navy Memorial Museum in Washington, D.C.

Conestoga’s baffling loss made headlines across the country, Delgado says, coming hard on the heels of the 1918 disappearance of the 542-foot Navy collier USS Cyclops and its 306 crew in the Bermuda Triangle — a region of the North Atlantic between Bermuda, Puerto Rico and Melbourne, Florida, where 20 planes and 50 ships have been lost over the last century — and the January 1921 grounding of the five-masted schooner Carroll A. Deering on North Carolina’s Diamond Shoals without a trace of her crew.

Speculation about Conestoga’s demise ran to the conspiratorial, this period in history being the first great Red Scare in America. Some feared Bolshevik agents had infiltrated U.S. ships’ crews with the intention of hijacking vessels such as the Deering and Conestoga, and taking them to Russia. Others hypothesized garden-variety mutiny.

Delgado, NOAA colleague Robert V. Schwemmer and several senior naval officers pieced together a much less exotic explanation for Conestoga’s loss. The ocean tug, probably with a barge in tow, departed Mare Island Naval Shipyard at 9 a.m. March 25 bound for Tutuila, American Samoa, by way of Pearl Harbor, Hawaii. She cleared the Golden Gate at 3:25 p.m. as winds built from 23 to 40 mph and seas turned nasty, according to weather archives NOAA consulted. Another ship relayed a garbled radio transmission much later, on April 8, but it is believed to have been from Conestoga around the time she sank. It said the tug was “battling a storm and the barge she was towing had been torn adrift by heavy seas.”

NOAA technical experts believe Conestoga was steaming past the Farallon Islands when its 41-year-old skipper, Lt. Ernest Larkin Jones, decided to turn around and make for Southeast Farallon, where there was a lighthouse and U.S. naval radio station and the vessel might find safe harbor in a protected cove or at the lighthouse landing.

“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,” NOAA’s report on the Conestoga discovery states. Delgado says the wreck lies on the seabed off Southeast Farallon, pointed northeast — right at the lighthouse — with its rudder hard to starboard.

Designed with low freeboard and a riveted-steel hull, the 17- year-old tug had earned a reputation for being “wet.” Delgado suspects she flooded and sank when a wave overpowered her. “The winds are 40, pushing 50,” he says. “They’ve lost their tow. Water is washing over her decks. It’s flooding in and coming in around the rivets. She begins to fill. The engineers call up to the wheelhouse, ‘We’re taking on water faster than we can pump it out.’ ”

Jones decides to run for safe harbor, but Conestoga founders before reaching the island. “He made the right choice,” Delgado says. “The sad fact is he almost made it.”

Responding to queries from crewmen’s families, the Navy didn’t discover that Conestoga was overdue at Pearl Harbor until April 26, nearly three weeks after a miscommunication from Hawaii reported that she had arrived safely April 6.

The Navy undertook an unprecedented 11-day search — the most exhaustive at that time for a missing U.S. vessel — dispatching 60 ships and dozens of airplanes to sweep 300,000 square miles around Hawaii. On May 17, the steamship Senator stumbled upon a derelict lifeboat with a brass letter “C” on its bow 650 miles west of Manzanillo, Mexico, and 30 miles off Clarion Island. Another search ensued to no avail. On June 30, 1921, the Navy declared Conestoga and her crew lost at sea.

The first inkling of the tug’s whereabouts came in August 2009, when contractors working for the NOAA Office of Coast Survey on the fishing vessel Pacific Star documented a probable uncharted shipwreck while doing a hydrographic survey of the Farallon Islands with multibeam sonar. The target appeared to be a tug.

Five years later, in September 2014, a NOAA Maritime Heritage expedition aboard the research vessel Fulmar deployed remotely operated vehicles at the wreck site and confirmed the target was a steel steam-powered tugboat of about 170 feet with a 26-foot beam. She was lying on the seabed on an almost even keel with a slight list to port and a portion of her hull embedded in sediment. Archival research uncovered no other missing vessel of that description in that vicinity except USS Conestoga — its fate one of the great mysteries in U.S. naval history.

Delgado and Schwemmer were at a maritime heritage conference in Norfolk, Virginia, shortly after returning from the expedition, and Schwemmer was reviewing video of the wreck in his hotel room when he spotted something they hadn’t seen earlier. Schwemmer called Delgado with exciting news. “There’s a gun sitting just inside the wreck,” he told Delgado. “You’ve got to get up here right now.”

It was a 3-inch, 50-caliber naval gun that had fallen through the rotting wooden deck — proof positive this was Conestoga. “It was a breakthrough moment,” Delgado says.

Other identifying features that match drawings and photographs of the ship include its size; the four-blade, 12-foot-3-inch-diameter propeller; the triple-expansion steam engine and boilers; the steam steering gear and steam towing winch with twisted wire on the drum (from losing its tow); the number and location of mooring bitts, portholes and ventilators; the shape of the stern; and two porcelain marine heads.

The remote vehicles found no human remains in the wreck, but Conestoga is a maritime gravesite for her 56 sailors and is protected by the Sunken Military Craft Act, which prohibits unauthorized disturbance of sunken military vessels or planes owned by the U.S. or any foreign government, NOAA says.

“This was a group of guys that heroically did their duty right up to the end,” Delgado says. “Sometimes the sea is just too powerful, and it has no mercy.”

Built in 1904 by the Maryland Steel Co. in Sparrows Point, Maryland, for the Philadelphia and Reading Transportation Line, Conestoga was acquired by the Navy in 1914 for use as a fleet tender and minesweeper. Assigned to the submarine fleet and fitted out in Philadelphia, Conestoga performed towing duties along the Atlantic coast, transported supplies and guns, escorted convoys to Bermuda and the Azores, and operated with the American Patrol Detachment around the Azores, according to the Navy.

At the end of World War I, she was attached to a naval base in the Azores, where she towed disabled ships and escorted convoys until her arrival at New York in 1919, when she was assigned to harbor duty in Norfolk, reclassified as a fleet tug and ordered to duty as a station ship at Tutuila, American Samoa. Conestoga underwent alterations and fitting out at Norfolk, cleared Hampton Roads in November 1920 towing a coal barge, and put in at San Diego in January 1921 and then Mare Island in February for repairs before setting out for American Samoa in March.

This article originally appeared in the August 2016 issue.