Coastal Defense Weapons Deployed near Los Angeles at the beginning of World War II by Jim Shneer

Coastal Defense Weapons Deployed near Los Angeles at the beginning of World War II

by Jim Shneer

In my last article, I wrote about the large guns deployed at Fort MacArthur as part of World War II defenses. Many other smaller weapons were deployed and in a much more timely manner. When the war came to the United States in December of 1941, Fort MacArthur's seacoast defense mission's scope of responsibility, for the first time, went beyond just the defense of the Port of Los Angeles. Until the start of the war, all of its facilities and weapons were confined to Palos Verdes, Fort MacArthur and nearby surroundings. With the Imperial Japanese Navy now a real threat and ample evidence of a Japanese presence in our coastal waters, a topic which I will address in a future article, protection of the entire coastline extending both north and south was needed. New fortifications and guns were developed based on a 1940 plan for harbor defense improvements, as well as new fire control sites and searchlight batteries.

Intended as early and temporary defenses, 155 mm M1918 guns, under the command of Fort MacArthur were emplaced from Santa Barbara to Costa Mesa. The 155 mm (about 6.1") gun was based on a World War I French design, which is why the gun's caliber is specified in millimeters.

A total of 15 sites were developed with two 155 mm guns each. Each site was prepared with Panama mounts. The term Panama mount describes a gun mount developed by the U.S. Army in Panama during the 1920s for fixed coastal artillery positions. The mounts could be constructed as either full, 3/4 or half circles of steel rail set in concrete with a diameter of approximately 36 feet. A concrete column with a diameter of ten feet was constructed in the center of the circle to support the gun and carriage. The concrete column was connected to the outer concrete ring by concrete beams for alignment/stability. Originally traverse was accomplished with several men and pry bars to move the trailing arms around the steel ring. Later installations included a geared steel ring just inside of the outer steel rail for improved traverse. The Canon de 155mm GPF, designated 155 mm gun M1917 (French-made) or M1918 (US-made) in U.S. service, was often married with Panama mounts.

The northern most guns under the command of Fort Macarthur were known as the Ventura Tactical Battery group and were located in Santa Barbara, Ventura, Oxnard and Port Hueneme. The only visible remains of these batteries are the two Panama mounts of the Ventura battery which are sometimes visible at low tide.

The other 155mm batteries under Fort MacArthur's command were at Pacific Palisades, Playa Del Rey, El Segundo, Redondo Beach, Rocky Point in Palos Verdes Estates, Long Point where the Terrenea Resort is now located, the Upper Reservation of Ft. MacArthur, Bolsa Chica and Costa Mesa. One Panama mount is easily visible at Fort MacArthur just south of the Korean Bell.

The location of the battery at Rocky Pont is shown in the following map. Three mounts, numbered in the map below were constructed there but only two ever had guns mounted.

Google Maps

Newspaper photograph of the Long Point Battery during World War II (Fort MacArthur Museum)

155mm Panama mount at Fort MacArthur (author's collection)

155mm Panama mount at Fort MacArthur (Google Maps)

The other remaining Panama mounts are within the Bolsa Chica Nature Reserve.

Location of the mounts within the Bolsa Chica Reserve (Google Maps)

One of the Panama mounts in Bolsa Chica (author's collection)

Both mounts in a satellite view (Google Maps)

One larger weapon became operational very early in the war. The Manhattan Beach Military Reservation was established in December 1941 on 13.203 acres of land. Two Mark IV M3A2 8" railway guns were initially emplaced on December 27, 1941 at Railroad Avenue and 14th Street in Manhattan Beach on the Santa Fe tracks which ran on what is now the green belt that separates Ardmore Avenue from Valley Drive, pending the construction of a rail spur and support structures that were completed in August 1942. The battery came to be called Eubank after its commander. After completion of construction, the railroad guns were moved into fixed positions on the high ground on 18th Street. Two powder and two projectile storage structures were built adjacent to the siding. Two fake rollaway farmhouses were used to conceal the railroad gun cars when not firing. These new guns with their 47° elevation could hurl their 260 pound projectiles for up to twenty miles. The guns also featured a unique rotating turntable built right on the carriage which, along with the use of outriggers, enabled the gun to fire 360° from the track without the complicated position preparation required for Battery Erwin. The railroad guns remained emplaced until they were ordered sent to the Sierra Ordnance Depot on April 19, 1944 and moved there on April 22. The area is now residential housing.

Manhattan Beach Reservation Boundary overlaid on a street map of Manhattan Beach

Army drawing of Battery Eubank. Note that "up" in the drawing faces approximately southwest.

8" railway gun (Fortwiki)

8" railway gun (fortwiki)

Jim is a former aerospace engineering manager who, since retiring, has become an author and speaker on a variety of military subjects. To read more about his work, please visit https://easyreadernews.com/the-battle-that-didnt-happen/. To learn about the military history of Fort MacArthur and Palos Verdes, please visit http://www.lulu.com/shop/james-shneer/exploring-the- military-history-of-fort-macarthur-and-palos-verdes/paperback/product-23784472.html to purchase a copy of his recent book.