I have a book project underway on my South Bay work that has a series of deadlines in the near term. This will put the coastal defenses project on the back burner for a while.
Hill 640 fire control stations with Stinson Beach in the distance.
As coastal artillery guns became larger, and their range increased, growing demands were placed on the fire control systems that targeted potential naval targets. By World War II the 16” guns of Battery Townsley and Battery Davis could fire a projectile 25 miles to sea. And there is a lot of sea out there at that range. To be effective the projectile would have to strike its target and that is where the artillery fire control system came into play.
Fire control station, Battery Smith Guthrie (courtesy GGNRA photo archive).
Fire control systems basically sighted targets from multiple vantage points along the shore. The vantage points were connected by baselines of known relationship. The sighting direction from each fire control station was transmitted to a central fire control plotting room where the readings were fed into an analog computer, essentially adjustable arms on a large plotting table (see video). The coordinates of a target ship were updated at 20 second intervals to establish a ship trajectory, A projectile fired by the 16” guns was in the air for about 90 seconds so several intervals of plotting would occur while the load was in flight.
Fire control stations for Battery Construction 243 (foreground) and Battery Construction 129.
Coastal batteries with smaller weapons could use fire control stations that were relatively close to each other. However, the range of the 16” guns required fire control stations that were quite far apart. In the Bay Area these began down past Pacifica to the south and ranged all the way up to Wildcat in Pt. Reyes. The Hill 640 Military Reservation, located on coastal bluffs just south of Stinson Beach near the intersection of Panoramic Highway and Highway 1, had five fire control stations with each station associated with a different 16” gun installation. The site has fire control stations for completed batteries (Townsley and Davis) and unfinished batteries (129 and 243) plus a fifth fire control station of unknown association. It is interesting that while the fire control stations all belonged to the same era they have different designs. There must be a story behind this circumstance. It is also interesting that targeting information was not shared between the batteries.
The 16″ gun being moved to its cradle adjacent to Battery Townsley, and the serpentine path it took to get there.(stitched panorama)
On October 1, 2012 I spent an interesting day out at the Marin Headlands watching the ingenious riggers of the Bigge Crane & Rigging Company move a 16” gun up the hill to Battery Townsley. Battery Townsley in the Marin Headlands and Battery Davis on San Francisco’s Ocean Beach were the two Bay Area batteries armed (of four planned) with 16” guns in World War II. Each battery had two gun emplacements within a huge concrete construction housing guns, munition storage, generators, and in the case of Townsley up to 150 resident troops.
The 16″ gun barrel waiting at the Rodeo Beach trailhead before the climb to Battery Townsley. The barrel is loaded on carriages with large diesel trucks pushing and pulling.
In the late 1930s, with war already underway in Spain and China, global tensions were building steadily. In the United States, strategists called for a modernization of our long neglected coastal defenses and by 1937 projects of this sort were underway in several Bay Area locations.
A view over Battery Townsley’s southern gun emplacement toward Rodeo Beach and Pt. Bonita.
The defense build up must have been a daunting challenge for planners. Aircraft had matured greatly in the preceding decade and coastal batteries could no longer hunker with impunity behind earthworks. They now needed protection from above in the form of reinforced concrete casemates, although some batteries would have to rely on the stealth afforded by less expensive camouflage netting. The coastal batteries of the time also had to confront the specter of battleships mounting sixteen-inch guns. This gave the opposition substantial firepower with a range of over 20 miles. The answer was to build new defensive batteries mounting the same sixteen-inch armament. San Francisco was home to what were essentially prototype batteries for these huge guns – Battery Davis at Fort Funston on the San Francisco coast and Battery Townsley on Tennessee Point at Fort Cronkhite in the Marin Headlands.
From the GGNRA archive – pouring cement for Battery Townsley, a 1938 construction photo.
I have always been a fan of ephemeral films – non-fiction films usually made for educational, industrial, or promotional purposes. While browsing the Coastal Defense Study Group Forum I found a link to two classic ephemeral films on YouTube, both having been brought to modern attention by Mark Berhow at the Fort MacArthur Museum in Southern California.
The first video shows a range of coastal artillery pieces being fired during drills including 12″ Mortars at Battery Howe in San Francisco, 14″ Railroad guns at Camp Pendleton, and a 16″ gun at Battery Townsley in the Marin Headlands (at 4:00 into the clip).
The second film is a c, WW II Signal Corps training video that explains fire control for coastal artillery.
Batteries Rathbone and McIndoe (essentially one battery) are similar in many ways to their Ft. Barry neighbors Batteries Smith and Guthrie. Both sites are late Endicott period projects that served through WW II – a ripe old age for coastal defenses. Both sites featured four emplacements mounting six-inch, rapid-fire guns on barbette carriages. Both sites were constructed around 1904 and operated as a single battery (Rathbone to the south and Guthrie to the north) until being split into paired two-gun batteries, reorganizations that occurred in the early 1920s. This was when McIndoe was added to Rathbone and Smith was added to Guthrie. Battery Rathbone lost a pair of guns during WW I but they were returned within a year.
The batteries as seen from the base of the clouds.
Batteries Rathbone McIndoe sit atop a south-facing ridgeline on the northern side of the Golden Gate Straight. At 350 feet above sea level they have a sweeping view of the straight and firing lines to its main and south approaches. The Thompson report does mention WW II era earthwork to widen the firing lines on the right flank.
Looking east toward Hawk Hill and the Golden Gate Bridge (hidden in the clouds).
A KAP view of Battery O’Rorke with Rodeo Beach and Ft. Cronkhite in the background, August 2012.
In retrospect, it seems the useful life of any particular coastal battery, at least as state-of-the-art defense, was quite limited. Those designing a defense strategy faced regular advances in the offensive capacities of potential naval opponents. The prospect of the latest generation of naval armament laying offshore and lobbing shells from outside the range of dated coastal defenses served as impetus for new defensive batteries with greater and greater range.
As the guns of San Francisco’s coastal defenses grew larger, so did the complexities of manufacturing, transporting, storing, and loading ordnance. The sixteen-inch guns of WW II fired projectiles weighing over a ton, and did so rarely due to the mechanical stress, and one imagines expense, of firing.
The Golden Gate National Recreation Area has gathered a fine archive of documentary images related to San Francisco’s coastal defenses. The collection spans from the 1880s through the 1990s and is great fun to browse.
Edmund Glowacki at Battery Smith-Guthrie, cWWII.
A sweeping panorama of the Marin Headlands. Battery Smith-Guthrie is visible in the center of the image. The panorama is best when viewed large.
Battery Smith-Guthrie, located in the outer reaches of the Marin Headlands, is one of the last of the San Francisco Endicott-era installations. It was situated to have direct lines of fire covering the northern shipping lane leading to the Golden Gate Straight, a route running to the landward side of the Potato Patch Shoal.
Battery Smith-Guthrie with Pt. Bonita beyond.
Baker Beach, Ft. Winfield Scott, San Francisco
Located on the north end of San Francisco’s Baker Beach at just 45 feet above sea level, this battery was built during the latter part of San Francisco’s Endicott period construction program. Construction began in 1902 and the works were ready for gun installation in 1904. The battery features four gun emplacements originally designed for six-inch, rapid-fire guns on the disappearing carriages popular in that period.
View of the middle two gun emplacements, which remained in service through WW II.
Battery Chamberlin was operated in its original configuration of four guns from 1904 to 1917 for the mission of protecting the Golden Gate’s shipping lanes and mine fields. During World War I, the battery’s guns were dismounted and shipped east to serve in that conflict. In 1920, Battery Chamberlin mounted guns again – two six-inch guns on barbette carriages. These remained in service through World War II as Battery Chamberlin was among the six Endicott-era batteries that remained active through the end of that conflict.
A plan view of the demonstration gun with its canvas cover.