A U.S. Navy tugboat that disappeared after leaving San Francisco 95 years ago has been discovered by federal maritime investigators. The finding of the USS Conestoga ends the mystery of the last Navy ship lost without a trace in peacetime, according to a statement released by the National Oceanic and Atmospheric Administration.

"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 tugboat, with 56 officers and sailors, left San Francisco Bay headed to Pearl Harbor in Hawaii in March 1921. It never reached its destination.

The NOAA statement says the ship was known as a "wet vessel," prone to taking on water in choppy seas:

"Weather logs indicate that around the time of Conestoga's departure, the wind in the Golden Gate area increased from 23 miles per hour to 40 miles per hour, and the seas were rough with high waves. A garbled radio transmission from Conestoga relayed later by another ship stated the tug was 'battling a storm and that the barge she was towing had been torn adrift by heavy seas.' "

A massive air and sea search was focused near Hawaii, but it failed to locate the Conestoga.

In 2009, NOAA investigators, with the help of sonar images, located wreckage in 189 feet of water about 3 miles off the Southeast Farallon Island near San Francisco. A full investigation began in 2014 and a year later, NOAA confirmed that it had found the Conestoga.

Underwater cameras recorded images of the tug lying largely intact. Divers confirmed many features of the Conestoga, including its steam engine and boilers, as well as a single, 3-inch, 50-caliber gun mounted on the main deck.

No human remains are in evidence. Federal law prohibits the unauthorized disturbance of a sunken military vessel or plane.

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