El Capitan was a side-wheel steam-powered passenger ferry operated on San Francisco Bay

San Francisco Bay

San Francisco Bay is a shallow, productive estuary through which water draining from approximately forty percent of California, flowing in the Sacramento and San Joaquin rivers from the Sierra Nevada mountains, enters the Pacific Ocean...

. The ferry was built for the Central Pacific Railroad

Central Pacific Railroad

The Central Pacific Railroad is the former name of the railroad network built between California and Utah, USA that formed part of the "First Transcontinental Railroad" in North America. It is now part of the Union Pacific Railroad. Many 19th century national proposals to build a transcontinental...

 in 1868 in anticipation of completion of the First Transcontinental Railroad

First Transcontinental Railroad

The First Transcontinental Railroad was a railroad line built in the United States of America between 1863 and 1869 by the Central Pacific Railroad of California and the Union Pacific Railroad that connected its statutory Eastern terminus at Council Bluffs, Iowa/Omaha, Nebraska The First...

. The ferry offered connecting service to San Francisco for train passengers arriving in Oakland, California

Oakland, California

Oakland is a major West Coast port city on San Francisco Bay in the U.S. state of California. It is the eighth-largest city in the state with a 2010 population of 390,724...

. El Capitan collided with the Central Pacific ferry Alameda in dense fog on 20 February 1879. The hull flooded from a hole forward of the port side paddle box, and the ferry sank onto a mud bar. She was towed to a shipyard for repair the following day. El Capitan spent its last decade crossing the Carquinez Strait

Carquinez Strait

The Carquinez Strait is a narrow tidal strait in northern California. It is part of the tidal estuary of the Sacramento and the San Joaquin rivers as they drain into the San Francisco Bay...

 between Crockett

Crockett, California

Crockett is a census-designated place in Contra Costa County, California, United States. The population was 3,094 at the 2010 census...

 and Vallejo

Vallejo, California

Vallejo is the largest city in Solano County, California, United States. The population was 115,942 at the 2010 census. It is located in the San Francisco Bay Area on the northeastern shore of San Pablo Bay...

before being retired in 1925.