Washington: A US Navy ship that went missing 95 years ago with 56 aboard has been found off San Francisco, ending one of the biggest mysteries in US naval history, authorities said on Wednesday.

The USS Conestoga tug boat, which disappeared on March 25, 1921 after departing San Francisco on its way to Pearl Harbor in Hawaii, was the last US Navy ship to be lost in peacetime, the Navy and National Oceanic Atmospheric Administration said in a joint statement.

‘After nearly a century of ambiguity and a profound sense of loss, the Conestoga’s disappearance no longer is a mystery,’ said Manson Brown, assistant secretary of commerce for environmental observation and prediction and deputy NOAA administrator.

The wreckage was initially detected in 2009 at a depth of 189 feet (58 meters) by a NOAA survey team working near the Farallon Islands, about 30 miles west of San Francisco.

The Conestoga wreckage, located three miles off Southeast Farallon Island in the Greater Farallones National Marine Sanctuary, was positively identified in October 2015. Experts believe the ship sank as its crew tried to reach a protected cove amid stormy weather.

The wreck is on the seabed and largely intact, although the wooden deck and other features have collapsed due to corrosion and age, the news release said. The hull is draped with anemones and various species of marine life are present at the site.

Video collected by remote controlled vehicles used to explore the wreckage revealed details consistent with the Conestoga, including the four-bladed propeller, steam engine and boilers, porthole locations, large towing winch with twisted wire on the drum and a 50-caliber gun mounted on the main deck.

No remains found

No human remains were found but the wreckage is protected by a law prohibiting unauthorised disturbance of sunken military vessels and planes.

The Conestoga left San Francisco and headed to Pearl Harbor with a final destination of Tutuila in American Samoa.

Weather records showed that winds in the area about that time increased from 23 to 40 miles per hour (37 to 64 kilometers per hour), and the seas were rough with high waves.

When the ship didn’t arrive as scheduled at Pearl Harbor some 2,400 miles (3,860 kilometers) away, the Navy launched a massive sea and air search operation, but focused its efforts around Hawaii.

Two months later, a ship found a lifeboat with the letter ‘C’ on its bow off the Mexican coast, and the search was moved to that area.

The search for the missing ship was covered by American media for months, much like the present-day search for Malaysia Airlines flight MH370 which went missing two years ago while flying from Kuala Lumpur to Beijing.

Originally built to tow coal barges for the railroad, the Navy bought Conestoga in 1917 during World War I. It operated on the US Atlantic coast and off the Azores in the Atlantic Ocean before being assigned to Norfolk, Virginia in 1919.

The Navy had declared the Conestoga and its crew lost on 30 June 1921.