page_title: Maritime history of California
section_title: California lighthouses
hierarchical_section_title: Maritime history of California / California lighthouses
context_page_description: In the California coast, the use of ships and the Pacific Ocean has historically included water craft, fisheries, shipbuilding, Gold Rush shipping, ports, shipwrecks, naval ships and installations, and lighthouses. The maritime history of California can be divided into several periods: the Native American period; European exploration period from 1542 to 1769; the Spanish colonial period, 1769 to 1821; the Mexican period, 1821 to 1847; and United States statehood period, which continues to the present day.
context_section_description: A lighthouse is a tower, building, or other type of structure designed to contain a flashing light to warn of hazards or to aid navigation primarily at night. The lights now flash on and off in a predetermined sequence to identify which light they are. Lighthouses are used as an aid to nighttime or fog-bound navigation for ship pilots and Captains at sea or on inland waterways. They warn of dangerous coastlines, points of land, hazardous shoals, rocks and reefs, or mark ship channels or harbor entrances. Under clear weather a light can be seen at night about 16 miles (26 km). Now in areas of fog the lights are typically combined with a foghorn. Before foghorns were developed cannons and/or large bells (rung by clockworks) were used to warn of fog shrouded hazards. The flashing lights are usually mounted on towers or other prominent structures built on points of land, rocks or shoals near the sea. Some are built on pilings, caissons or mounted on isolated rocks. Some lighthouses are mounted on anchored Lightships when no other economical alternative exists.
  In the 1850s the light was emitted from a system of oil or kerosene lamps. The light was concentrated and focused with a system of Fresnel lenses. In the 1850s the light was provided from a burning wick in a whale oil lamp. Later, as kerosene became available, the light was provided by burning kerosene. They typically used an Argand lamp which featured a hollow wick in a glass chimney for better, brighter, combustion with a silvered parabolic reflector behind the lamp to direct and intensify the light output. All oil fired lamps used burning wicks to make the light—giving rise to one of the lighthouse keeper's nickname as "wickies" as they spent a great deal of their time trimming the wicks on their lamps in order to keep them burning brightly with minimum sooting. In the 1850s their lights were rotated using clockworks, usually powered by falling weights attached to chains. Many lighthouses had vertical shafts in them so the weights could drop the height of the tower. This provided a longer time period before the weights would have to be pulled up again by the lighthouse keepers to power the rotation mechanism. Some had to be rewound as often as every two hours.
  To keep the clockworks wound, refuel the oil needed to keep the light going and keep the lighthouse equipment and windows clean and maintained the lighthouses were typically manned with a lighthouse keepers of from one to five men or women. Only the fortunate few lighthouses were located where the crews could live in comfort and/or socialize with others. Because these assignments were often in lonely fog bound locations the crews often rotated on and off duty every few months. Families sometimes were paid to run a lighthouse that way the husband, wife and children could keep together.
  Starting in the early 1890s the lights were provided by burning acetylene gas generated in situ from calcium carbide reacting with water. The acetylene-gas illumination system could reliably be turned on and off automatically, enabling automated unattended lighthouses to be used. Once electricity became available, often provided by one or more diesel electric generators in remote locations, the light source was gradually converted to electrical power and the clockworks were run by some type of electric motor. For example, of modern changes, the Chatham Light in Chatham, Massachusetts (near the "elbow" of Cape Cod) the light was converted in 1969 from its Fresnel lens light assembly to a Carlisle & Finch DCB-224 rotating light generating over 2.8 million candela. This is visible for over 20 nautical miles on a clear night and has a self-changing bulb assembly to replace burned-out bulbs.
  Once widely used, the number of operational lighthouses has declined due to the expense of maintenance and their replacement by modern electronic navigational aids. Nearly all lighthouses today, that are still being used, are automated to the extent possible with power often provided via solar cells and large batteries in inaccessible areas. Today
caption: Point Reyes Lighthouse
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