Mile Rocks San Francisco Bay California

Got this stamp at Golden Gate NRA on a visit in 2011  

The southern side of the entrance to the Golden Gate is dotted with a family of dangerous wave-swept rocks that includes Black Head Rock, Lobos Rock, and Pyramid Rock. The two northernmost, and thus most dangerous to navigation, are Mile Rock and Little Mile Rock, known together as Mile Rocks. Located only 0.4 miles from the closest shore, it seems Mile Rocks are so named because the rocks are one mile south of the main shipping channel leading into San Francisco Bay.
In November of 1889, the Lighthouse Service placed a bell buoy near the rocks. However, the strong currents in the area would pull the buoy beneath the surface of the water and even set it adrift. Frustrated lighthouse engineers concluded that the rocks “must always be a menace to navigation as long as they exist,” as building atop the rocks or dynamiting them below the surface didn't seem practical. Then on February 22, 1901 the City of Rio de Janeiro, inbound from Hong Kong in heavy fog, struck Fort Point Ledge and sunk in just eight minutes. Of the 210 aboard, 128 were lost. The Lighthouse Board concluded that the shipwreck, the worst in San Francisco’s history, might not have occurred if a fog signal could be heard considerably seaward of the ledge.

Mile Rocks Lighthouse Photograph courtesy U.S. Coast Guard

The tragic wreck provided ample motivation to overcome the obstacles inherent in constructing a lighthouse atop Mile Rock. In 1904, James A. McMahon of San Francisco was awarded the contract to build the lighthouse, and set off with a skilled crew to assess the construction site. After seeing the seagirt rock on which the lighthouse was to stand, the crew promptly quit. A second crew, consisting of deep-sea sailors recruited from San Francisco’s Wharf and thus more familiar with the sea, was assembled, and work began in September of that year. A small schooner, the Rio Rey, was anchored near the rocks and served as floating quarters for the crew.
A good portion of Mile Rock, which measured 40 by 30 feet, was blasted away to provide a level foundation. Next, four-feet thick walls made of steel-reinforced concrete were built to a height of thirty-five feet to form the base of the tower. A cistern and fuel tanks were located within the base, with a heavy door at the base providing access for refueling. Atop the caisson, a three-tiered steel tower, capped by a lantern room, was constructed. Looking at the historic photograph to the right, it is easy to understand why it was called the steel wedding cake.
The first tier of the tower housed the engines for powering the station’s fog signal. The second tier was composed of two stories, with an office kitchen, and day room on the bottom floor, and two bedrooms and a bathroom on the second story. The third tier was used mainly for storage. The caisson and first tier were both oval, while the upper tiers and lantern room were circular. The top tier was used as a storage area, and the lantern room with its crosshatched window panes protected a third-order Fresnel lens, which was first lit during the winter of 1906.
Mile Rocks Lighthouse was always a “stag station”, as there was hardly enough room for the resident four keepers themselves. Couples came up with some innovative methods for maintaining contact. One keeper’s wife would walk the family dog out to Land’s End in the evenings and use a flashlight to signal a greeting to her husband.
Keepers were transported to the tower by boat and from its rocking deck they had to snag the Jacob’s ladder suspended from the tower’s catwalk. In rough seas, the bobbing boat would occasionally knock the keeper off the ladder, before he made the thirty-foot ascent.
In the 1960s, plans were being developed in the Coast Guard to automate Mile Rocks Lighthouse. The upper two tiers of the tower were slated to be removed, and the top of the truncated tower would be used as a helicopter landing pad. San Francisco Supervisor William Blake and the Conference of California Historical Societies both protested the automation plans. The Coast Guard however was determined to proceed with the cost-saving measure. In 1966 and at an expense of $110,000, the Coast Guard dismantled the lantern room and top two tiers of the lighthouse and constructed the landing pad. The San Francisco Maritime Museum tried to acquire the top forty feet of the lighthouse and place it on display at the foot of Hyde Street, but as saving the upper portion of the tower would have added $87,000 to the $110,000 contract for refurbishing the lighthouse, the living quarters were scrapped.

 Although the base of the tower is now painted with colorful orange and white bands, the beauty of the structure was greatly compromised when the tower was decapitated. One can only speculate at what role this truly unique tower would have today, if it had remained intact. One can view still view one of the more attractive remnants of the Mile Rocks Lighthouse, as its lens is currently in use at the Old Point Loma Lighthouse in San Diego.