Historic Point Cabrillo Lighthouse lens is once again guiding mariners after repairs

Almost 90 years after it was first installed in the historic Point Cabrillo Lighthouse, the 1937 motor that has long helped guide mariners through the night along the Mendocino Coast is back in service.

The famed British-built Fresnel lens that flashes from atop the more than century-old lighthouse had been stilled since Dec. 29, when a gear in the aging motor failed, shutting it down altogether until repairs could be made.

In the 275 days that ensued, a backup beacon was used to aid navigation on the central Mendocino Coast, generating a white flash every 10 seconds in keeping with the Point Cabrillo signature pattern.

But the giant, multifaceted lens is working again, thanks to expert attention and an overhaul of the motor, as well as the lens and lamp, parts of which have been cleaned, updated and re-lubricated, the Point Cabrillo Lightkeepers Association announced.

The nonprofit also arranged for a new paint job and replacement of the back doors of the lighthouse, which were destroyed during a Jan. 5 storm that flooded the first floor.

The composite lens is made of 90 glass prism pieces and was fashioned after the design developed by French physicist Augustin Fresnel in 1822. It is one of three in use in the United States that were built by Chance Brothers of England and was shipped around the Cape Horn to be put into service on the west coast of America, according to California State Parks.

It stands about as tall a human, with intricate workings that extend through the center of several floors of the light station, and is considered to be in good condition. But it was taken out of service in 1972 during a series of modernization steps, only to be restored in 1999 as part of the historic preservation of the entire site, which includes 11 other structures.

The Point Cabrillo Lighthouse, on a promontory midway between Fort Bragg and Mendocino, was once one of three on the North Coast, each flashing with a distinct pattern so mariners could distinguish one from the other in the dark, the association said.

Where the defunct Punta Gorda Lighthouse on the Humboldt Coast once flashed twice every 15 seconds, the Point Arena Lighthouse on the southern Mendocino Coast had a double white flash every six seconds, until a modern LED light was put into service, the Lightkeepers Association said. It now has a single flash every 15 seconds.

Construction of the Point Cabrillo Lighthouse was begun in 1908, amid a logging boom on the Mendocino Coast that contributed to the rebuilding of San Francisco after the 1906 earthquake, according to a Lightkeepers Association history.

Ships hauling logs along the rugged coastline needed navigational aid and got it when the lens was first illuminated in June 1909.

The lens, which amplifies the light and gives it a range of 13 to 15 miles, was first powered by a kerosene oil lamp, while the lens was rotated through a weighted clockwork mechanism that had to be cranked every two hours by the lightkeeper.

A bulb replaced the oil lamp in 1935. In 1937, an electric motor was installed to replace the hand-cranked clockworks.

The lighthouse and accompanying buildings are now part of Point Cabrillo Light Station State Historic Park, open each day of the year from sunrise to sunset.

The museum and gift house is open 11 a.m. to 4 p.m., with rare but occasional docent-led tours of the Fresnel lens.

More information is available at pointcabrillo.org/.

You can reach Staff Writer Mary Callahan (she/her) at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.