A Navy tugboat that sank nearly a century ago has been found by a team of government researchers off the San Francisco coast.

The USS Conestoga departed San Francisco Bay for Pearl Harbor in March 1921. But the boat never made it to Hawaii, and her 56-man crew was declared lost. The boat was never found, despite a search that covered hundreds of thousands of square miles and was the biggest air and sea search of its time.

On Wednesday, officials from the Navy and National Oceanic and Atmospheric Administration announced that the tug has been found about 30 miles off the coast, near the Farallon Islands.

NOAA is in the midst of a multiyear effort to map roughly 300 shipwrecks off in the waters off San Francisco.