Point Bonita Light

Point Bonita Light

Location	San Francisco Bay, California
Coordinates	37.815569°N 122.529604°W / 37.815569; -122.529604
Year first constructed	1855
Year first lit	1877
Automated	1980
Foundation	Masonry
Construction	Brick and Cement
Tower shape	Polygonal on building
Markings / pattern	white
Height	33 ft (10 m), 124 ft (38 m) above sea level
Original lens	Second order Fresnel lens
Current lens	Second order Fresnel lens
Range	18 nm
Characteristic	Occulting white once every 4s. Emergency light of reduced intensity when main light is extinguished. HORN: 2 blasts ev 30s (2s bl-2s si-2s bl-24s si).
Admiralty number	G4052
ARLHS number	USA-618
USCG number	6-0370

Point Bonita Light is a lighthouse located at Point Bonita at the San Francisco Bay entrance in the Marin Headlands near Sausalito, California. Point Bonita was the last manned lighthouse on the California coast.

History

The original Point Bonita Lighthouse, a 56-foot (17 m) brick tower, was located too high. Unlike the East Coast of the United States, the West Coast has dense high fog, which leaves lower elevations clear. The original light was 306 feet (93 m) above sea level so the second order Fresnel lens was often cloaked in fog and could not be seen from the sea. In 1877, the lighthouse was moved to its current location at 124 feet (38 m) above sea level. The United States Coast Guard currently maintains the light and fog signal. It is accessible to the public during limited hours (12:30 PM–3:30 PM) on Saturdays, Sundays, and Mondays. Up until 1940 the lighthouse could be reached without a bridge, but erosion caused a trail leading to the lighthouse to crumble into the sea. A wooden walkway was installed, but when that became treacherous the suspension bridge was built in 1954. The bridge was intended to mirror the design of the nearby Golden Gate Bridge.

As of January 6, 2010, the suspension bridge to the light house has been closed to public access. According to the Federal Highway Administration, the bridge, which is 56 years, has started to rust. It underwent repairs in 1979 and again in 1991, but the metal components are not able to stand up to the sea spray. The new span is set to open in March 2012. The new bridge construction is expected to cost between $850,000 and $1.3 million. The bridge will be made from tropical hardwood and steel suspension cables and attachments.

Historical Information from USCG web site:

• Point Bonita Light Station had the first fog signal on the West Coast. It was an Army surplus 24-pounder siege gun.
• This light is the only one in America that can be reached only by crossing a suspension bridge.
• In 1877 the lighthouse was moved to its current location because the original location was often too obscured by fog for the light to be visible from the bay. This location required the builders to overcome many challenges, including the need for a hand carved, 118-foot (36 m) long hard rock tunnel.

More than 300 boats ran aground near the Golden Gate during the Gold Rush years. One shipwreck, the SS City of Rio de Janeiro, is just a few hundred feet offshore from the light.

Image gallery

• 

  1856 Point Bonita Light – U.S. Coast Guard Archive

• 

  Point Bonita Light – U.S. Coast Guard Archive

• 

  Point Bonita Light detail

External links

• Lighthousefriends.com entry (photos and history)
• NPA Website about the light house