Harbor Defenses of San Francisco, 1891-1945

Endicott Era, 1891-1928 (including the Taft Era and World War I)

As the United States completed its westward expansion and continued to industrialize in the late 1800’s, the government turned its attention to establishing the United States among the world’s great military powers. The Navy expanded to become a truly international force, and the Army assumed responsibility for the defense of the nation’s coasts and ports. President Cleveland established the Endicott Board in 1885 for the purpose of modernizing fortifications. Chaired by Secretary of War William Endicott, the board recommended new defenses at 22 U.S. seaports. The new reinforced-concrete gun batteries that resulted are known as Endicott batteries, and in fact the Endicott Era of coastal defenses lasted 50 years, with some modification, until the end of World War II.

The Endicott Board deemed San Francisco Harbor second only to New York’s in strategic importance. As a result, an extensive series of forts, batteries, and guns were proposed for the harbor entrance, occupying both shores of the Golden Gate. In the Presidio of San Francisco construction began in 1891, when ground was broken for Battery Marcus Miller. On the north side of the Gate, Battery Spencer followed in 1893. Batteries were subsequently built south of the Presidio at Fort Miley (Land’s End), north of the Golden Gate at Fort Baker and Fort Barry, and in the inner-harbor, at Fort McDowell (Angel Island) and Fort Mason.

The Spanish-American War and the Philippine-American War that followed (1898-1902) increased the pace of military spending on the West Coast. In 1905, President Roosevelt asked his Secretary of War William Taft to head a board to update Endicott defenses. The Taft Board recommended further innovations including minefields, electrification, searchlights and telephonic communication. This development culminated in a targeting system, known as fire control, which used widely spaced observation posts scattered along the coast. These posts, called base-end stations, had 3-man crews that provided range, bearing and speed information to artillery crews, who then used this data to triangulate on and target a moving enemy ship.

In 1912, Fort Winfield Scott was formally established on the western portion of the Presidio to serve as a coast artillery post. It contained approximately 63 guns mounted at 15 gun batteries and was the headquarters for all other coast artillery posts in the Bay Area until they were disarmed after World War II.

The Coast Artillery soldiers lived in barracks within marching or driving distance of their gun batteries. Many considered the duty a privilege because it was close to the social life of San Francisco. The officers were trained at the Army’s elite coast artillery school in Fort Monroe, Virginia. The soldiers maintained the massive guns and practiced firing at targets miles out to sea. They received reports on their accuracy from pilots of the Army Air Corps flying overhead. The biplanes flew from Crissy Army Air Station, established in 1921 on the Bay Shore of the Presidio.

World War II Era, 1937-1948

Although airplanes were a minor factor in World War I, their threat prompted the Army to make additions to the defense system, including small, rapid-fire anti-aircraft guns and camouflage. The existing batteries could be covered with vegetation-colored netting, but if detected, they remained vulnerable to aerial bombing. Thus, the next, and last, generation of seacoast guns was mounted under thick concrete shields covered with vegetation to make them virtually invisible from above. Sixteen-inch guns, which fired 2,000 pound projectiles to a maximum range of 25 miles, were intended to keep the newest battleships from reaching striking range. Work on the first battery for guns of this type in the U.S. began in 1936 at Battery Davis in Ft. Funston, south of the Golden Gate. The first test firing took place in 1940, from Battery Townsley in Fort Cronkhite, north of the Gate and residents of San Francisco complained that the concussion broke their windows!

As World War II approached, the Army made further improvements to the Harbor Defenses of San Francisco. Additional base-end stations, mines, searchlights, and anti-aircraft guns were installed. After Pearl Harbor, the entire Western Defense Command was placed on high alert, but the three West Coast attacks that did occur caused only minor damage. In 1942, a Japanese submarine shelled an oil refinery near Goleta, Southern California, another sub fired upon Ft. Stevens, Oregon, and a balloon launched by the Japanese exploded in forest near Brookings, Oregon. The most important wartime development in coastal defense was radar, which vastly improved enemy detection and fire control around San Francisco Bay.

But World War II was much more than a time of "improvements" to weaponry. A vast change in the nature of warfare also occurred. Of greatest pertinence to harbor defense, the war was fought and ultimately won from the air. New types of warfare included amphibious assault on undefended coasts, carrier-based air attack, high-elevation bombing and atomic warfare. Defending a harbor against ships became a superfluous activity, and even before the war ended, some seacoast guns were scrapped to become new weapons, and soldiers of the heavy artillery were transferred to anti-aircraft or even infantry duties.

Just 2 years after the war, all guns remaining in the seacoast defenses of San Francisco were declared surplus, and the last weapons were removed in 1950. The Coast Artillery was deactivated that same year.

Learn more about World War II in the San Francisco Bay Area through a National Registry of Historic Places Travel Itinerary.

Last updated: December 11, 2020

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