When engineers working near Candlestick Park last March drilled deep into the ground for soil samples, they pulled up chunks of wood and figured it was an old pier.
They had no idea it was a century-old ship, let alone two.
But that became clear this week when the San Francisco Public Utilities Commission uncovered what maritime experts believe are a pair of scow schooners, 90-foot-long workhorse vessels that plied the bay shallows in the late 1800s to deliver hay, salt, bricks, pork, coal, lumber and other cargo.
Buried under more than 14 feet of sand and fill dirt, the 45-foot-long hull sections came to light at the mouth of an enormous trench that will house a new overflow sewage pipe for the Visitacion Valley neighborhood.
"These were the flatbed trucks of San Francisco Bay from the late 19th and early 20th century," said Jim Delgado, director of maritime heritage at the National Oceanic and Atmospheric Administration in Washington, D.C.
"They're largely forgotten now, but these scow schooners moved the goods that built the city and the Bay Area economy."