Mile Rocks Lighthouse

Mile Rocks Lighthouse is located on a rock about 1 mile (1.6 km) southwest of the Golden Gate Bridge, off of Lands End in San Francisco, California. It was completed in 1906, replacing a nearby bell buoy. In 1966, the light was automated, and the original 85 m (279 ft) tower of the lighthouse was demolished and replaced by a helipad. The lighthouse was at one time painted with alternating red and white rings, but as of 2017, the lighthouse is painted plain white.

Mile Rocks Lighthouse
Mile Rocks Lighthouse with helicopter landing on the top
San Francisco
Locationoffshore Lands End
San Francisco
California
United States
Coordinates37°47′34″N 122°30′37″W
Year first constructed1906 (first)
Year first lit1966 (current rebuilt)
Automated1966
Foundationmassive reinforced concrete enclosed with steel plates basement
Constructionsteel tower
Tower shapecylindrical tower with aerobeacon and helipad on the top (current)
3-stage cylindrical tower with balcony and lantern (first)
Markings / patternwhite and red horizontal bands tower (current)
white tower
Focal height49 feet (15 m)
Original lens3rd order Fresnel lens
Current lensaerobeacon
Light sourcesolar power
Range15 nautical mile 
CharacteristicFl W 5s.
Fog signalblast every 30s. continuously
Admiralty numberG4054
ARLHS numberUSA-496
USCG number6-0365
Managing agentUnited States Coast Guard[1]

[2]

[3]

History

In 1889, the United States Lighthouse Service placed a bell buoy near the rocks. However, strong currents in the area would pull the buoy beneath the surface of the water and set it adrift.

On February 22, 1901, the SS City of Rio de Janeiro wrecked on the rocks, which prompted the lighthouse to be built.[4] One hundred and twenty-eight persons, of 209 aboard, lost their lives when the ship sank.

The lighthouse was constructed by contractor James McMahon who hired sailors from San Francisco after his original crew refused to work in the dangerous conditions. Mile Rocks Lighthouse was finished in 1906 after considerable difficulty caused by the heavy seas and strong currents near the site.[4]

The rock upon which the lighthouse is built measures only 40 by 30 feet (12.2 by 9.1 m) at high water. The base of the tower is a large block of concrete protected by steel plating. Steel and concrete in the foundation weigh 1500 tons. The superstructure is made of steel and houses the fog signal apparatus and the quarters for the former keepers.

In 1966, the light was automated and the tower was removed, leaving only foundation and the first story. The top of the first story was modified to support a helipad for the US Coast Guard. The original third order Fresnel lens was transferred to the Old Point Loma Lighthouse in San Diego.

  • Mile Rocks Lighthouse in 1962, showing the original configuration.
  • Mile Rocks lighthouse, with Point Bonita and Marin headlands in distance
  • Mile Rocks Light with Container ship Sealand Balboa in December 2019
  • The lighthouse after modifications

See also

References
  1. Mile Rocks The Lighthouse Directory. University of North Carolina at Chapel Hill. Retrieved 11 June 2016
  2. California Historic Light Station Information & Photography United States Coast Guard. Retrieved 11 June 2016
  3. Miles Rock Light Lighthouse Friends. Retrieved 11 June 2016
  4. "Mile Rocks: A Bay Area Lighthouse Unlike Any Other". KQED. 18 January 2019. Retrieved 20 January 2019.
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