CABRILLO The Guns of San Diego Historic Resource Study

E. Advances in Coastal Defense, San Diego Harbor, 1901-1920

Twenty years after the Endicott Board made its report on seacoast fortifications, President Theodore Roosevelt directed Secretary of War William Howard Taft to review the national program and to evaluate recent developments. Among the Taft Board's more important findings were the organizing of coastal searchlights in batteries for illuminating harbor entrances and approaches; the electrification of fortifications, including lighting, communications, and ammunition handling; and a modern system of aiming. Of this last, historian E. Raymond Lewis writes that it was the most significant advance made in harbor defense fire control until the introduction of radar. Until now aiming had been done from individual guns with elementary instruments.

The new system, in contrast, was based on a combination of optical instrumentation of great precision, the rapid processing of mathematical data, and the electrical transmission of target-sighting and gun-pointing information. Of the several methods of fire control devised about the time, the most elaborate and precise made use, for a given battery, of two or more widely spaced sighting structures technically known as base-end stations. From these small buildings simultaneous optical bearings were continuously taken of a moving target, and the angles of sight were communicated repeatedly to a central battery computing room. Here sightings were plotted and future target positions were predicted.... The computed products were then translated into aiming directions which were forwarded electrically to each gun emplacement or mortar pit. [26]

In September 1905, a high-powered committee of officers visited Fort Rosecrans with the mission of revising the Endicott Board's findings regarding San Diego Harbor. [27] The Los Angeles District Engineer had been busy making improvements at San Diego even before the committee's arrival. Among other things, a central power plant had been constructed in "Power House Canyon" behind Battery Wilkeson in 1905. It served all the batteries and a 30-inch coastal searchlight that had been installed near Battery McGrath in 1902. Now the Board recommended the installation of three additional searchlights on Point Loma. [28]

The Taft Board did not recommend any additional artillery for San Diego, but as a result of its findings there was a definite, if gradual improvement in fire control for the existing batteries. The first fire control stations were often temporary in nature and few in number. Gradually, permanent stations were constructed with concrete walls and tar and gravel roofs. But a standard fire control system did not get installed at San Diego until World War I. When first built, these concrete structures were "open type stations." Then, in 1919, the Chief of Engineers directed that roofs be constructed for all of them. The base-end stations at this time received concrete and earth coverings, while the fort commander's and the fire commander's roofs were flat steel.

Maj. William C. Davis, commanding Fort Rosecrans, noted in 1913 that the completion of the Panama Canal would increase the commercial and strategic importance of San Diego Bay. It was time for the installation of standard fire control equipment. Army Engineers soon began preparing such a plan for Battery Wilkeson that called for two battery commanders' (BC) stations (Wilkeson was soon to be divided into two batteries), two primary stations (B¹), and two secondary stations (B²), the last to be built at Fort Pio Pico across the channel. Also, stations were to be built for the fort and fire commanders. [29]

By the end of World War I eight base-end stations, four on Point Loma and four at Fort Pio Pico, were in operation. Two of these stations, then called B1/3 and B1/4, remain on the east side of Point Loma within Cabrillo National Monument and are on the List of Classified Structures as HS8 and HS9. At that time they were the primary stations for Batteries Wilkeson and Calef. Also by 1918, all of North Island had become federal property, the Navy using the north half for aviation purposes and the Army having established Rockwell Field in the southern half. The Engineers took advantage of this situation and moved four base-end stations from Fort Pio Pico farther east on the newly acquired land, thereby lengthening the base lines by nearly 2,000 feet. (Sufficiently long base lines at Point Loma had long been a problem because of the rugged terrain of the reservation.) In 1917 the Chief of Ordnance notified the Coast Artillery that fourteen Warner and Swasey azimuth instruments, Model 1910, would be sent to Fort Rosecrans for use in the new fire control stations. The position finder instrument in use at that time was the Swasey Depression Range Finder, Type A, Model 1910. [30]

Although the standard fire control system for the defenses of San Diego had not been completed by 1920, the Corps of Engineers turned over a substantial number of stations to the commanding officer that year:

San Diego's Endicott batteries had concentrated on defending the entrance channel. Only Battery Wilkeson could have participated in a major naval engagement. While batteries had been projected for Point Loma and elsewhere, they had not yet been funded. In 1913, Maj. William C. Davis wrote the Adjutant General of the Army outlining the deficiencies of the defenses. A modern naval power, with its new long-range fighting power and efficiency, could attack and maneuver in the area south of Coronado and far outclass Wilkeson's 10-inch guns. An enemy fleet off Ocean Beach could bombard and take in reverse all the fort's batteries and bombard downtown San Diego and all the inner harbor. [32]

In a similar vein the Los Angeles District Engineer described the defenses: "Only Battery Wilkeson is apt to participate in a naval engagement of serious magnitude, for the other batteries cover the mine fields and the immediate entrance to the harbor only." The weak point in the defenses, he said, was the west side of Point Loma where even enemy gunboats could approach unopposed: "There is no gun of any calibre now available to protect this side of the Point." Before the end of 1915, help was on the way. The commanding general of the Western Department learned that four 12-inch mortars, authorized at the last session of Congress, would be shipped from Fort Morgan in Mobile, Alabama. [33]

The Engineers began work on two mortar batteries, each having four mortars in two pits, at the end of 1915. Battery John White was constructed in a deep ravine (Power House Canyon) behind the post and Battery Whistler was constructed near the northern boundary of the reservation. The first was named in honor of Col. John Vassar White, a graduate of the U.S. Military Academy and a veteran of the Artillery Corps. Battery Whistler honored the memory of Col. Joseph Nelson Garland Whistler, an infantry officer who fought in both the Mexican and Civil Wars. Although the engineers completed construction in 1916, the mortars and their carriages were delayed in arriving. The mortars were not proof-fired until the end of 1918 and the batteries were officially transferred from the Engineers to the commanding officer of the Coast Defenses of San Diego in August 1919.

Engineers emplaced the mortars and carriages as follows:

Battery Whistler

Battery John White

At the same time considerable planning took place for adding six 6-inch rapid-fire guns to the harbor's defenses: two at Billy Goat Point on the east side of the peninsula, at elevation 99 feet; two at the south end of Point Loma, one-quarter mile northwest of the new lighthouse, elevation 78 feet; and two on the western side of Point Loma near the north boundary, elevation 128 feet. The estimated cost of the three batteries and the necessary fire control stations came to a grand total of $842,000. The Secretary of War approved the project in February 1918 and directed that the cost figure be included in the 1920 defense estimates. The Congress did not make funds available and many years passed before 6-inch guns again were considered for San Diego. [35]

Lt. Col. W. F. Hase inspected the Fort Rosecrans batteries early in 1918 and discovered that the sea was undermining 3-inch Battery James Meed at Fort Pio Pico. His recommendation that the guns be dismounted and the battery abandoned was approved. Since the 5-inch guns at Battery McGrath had gone to war, the Engineers modified its emplacements and mounted Meed's guns in their stead in May 1919. [36]

World War I stimulated several developments in San Diego coastal defenses. Among them was the 1917 authorization to construct an army radio station at Fort Rosecrans. Engineers located it 1,000 feet northwest of the old lighthouse with the towers between the two. The building cost approximately $2,500 and the towers $1,150. It was operational in 1918 but for some reason it was not turned over to the Coast Artillery until 1919. This did not prevent a "very zealous and enthusiastic radio instructor, Lt. MacFadden" from placing the apparatus in service prematurely. The district engineer demanded an explanation and got an apology. A couple of months later, a naval lieutenant officially tuned in the equipment and the artillery engineer took charge of the station. [37]

The Taft Board's recommendations for batteries of coastal searchlights became a reality on Point Loma between 1918 and 1919. The Chief of Engineers approved plans for eight 60-inch searchlights arranged in four batteries:

Searchlights 1 and 2 - near the base of a hill on land in the northwest part of the reservation, land that was recently transferred from the naval reservation, at elevations of 190 feet and 97 feet respectively. Both to be new lights on elevating lifts. Power house nearby in a ravine.

Searchlights 3 and 4 - near the extremity of Point Loma, elevations 97 and 285 feet. Number 3 to be in upright shelter and mounted on a track (a reconstruction of an existing installation). Number 4, a new light on an elevating lift. The power house to be a reconstruction of existing house.

Searchlights 5 and 6 - near base of a hill on southeast portion of Point Loma at elevations 218 and 144 feet respectively. Both to be new lights. Number 5 to run on a track between operating position and naturally protected aboveground shelter. Number 6 to be on elevating lift. Power house in a ravine affording partial protection between the two lights.

Searchlights 7 and 8 - on a sand spit at Fort Pio Pico. One is the existing 60-inch light, the other, new. Power house to have artificial protection. Lights to be on tilting towers with a sand parapet in front.

The plans called for roads, "mere graded roads without surfacing," to the power house for searchlights 1 and 2 and for searchlights 5 and 6. Because the site selected for Searchlight 6 potentially interfered with the proposed 6-inch battery on Billy Goat Point, it was constructed just to the west at an elevation of 210 feet. Four 25 kw, D.C. generation sets were purchased for searchlights 1, 2, 5, and 6. The Engineers completed shelters for these four searchlights in April 1919, at an approximate cost of those shelters having elevators of $2,300 each. All shelters were reinforced concrete; those above ground had steel doors; and those underground had sliding steel roofs. [38]

Shelter for coastal searchlight no. 5, constructed in 1920. Located on Bayside Trail, Cabrillo National Monument. Photo by U.S. Army Corps of Engineers, 1920. Courtesy of U.S. Army Corps of Engineers, Los Angeles District.

Searchlight Number 5 in operating position, 1920. Searchlight Number 6 is located directly behind and to the north of this searchlight. Photo by U.S. Army Corps of Engineers, 1920. Photo courtesy of U.S. Army Corps of Engineers, Los Angeles District.

Searchlight Number 6 in operating position, 1920. Photo by U.S. Army Corps of Engineers, 1920. Photo courtesy of U.S. Army Corps of Engineers, Los Angeles District.

Searchlight shelter Number 6 today. Portion of rails still in place. Located on Bayside Trail, Cabrillo National Monument. Photo courtesy of George R. Schneider.

Searchlight Number 5 in operating position. Photo by U.S. Army Corps of Engineers, 1920. Photo courtesy of U.S. Army Corps of Engineers, Los Angeles District.

Old Point Loma Lighthouse between 1912 and 1914. The wife of an army noncommissioned officer, who was living in the structure, wrote that since the photo was taken a porch had been built along the front of the building. She also said there was a store where the window was broken and she had her kitchen where the curtains show. Photo courtesy of Maj. Gen. George Ruhlen, U.S.A. Ret.

Fort Rosecrans' first army radio station, built in 1918. This structure later served at the National Park Service's early superintendent's office. It is now a storage building. Photo by E. Thompson.

Roof of searchlight shelter Number 15. This oceanside searchlight is found west of Gatchell Road at Cabrillo National Monument. Photo courtesy of George R. Schneider.

Sixty-inch coastal searchlight. Three of these were mounted within today's Cabrillo National Monument: Nos. 5, 6, and 15. Photo courtesy of National Archives, Los Angeles Branch, RG 77, OCE, Box number lost.

Power plant for searchlights 5 and 6 as it looks today. Located on Bayside Trail, Cabrillo National Monument. Photo courtesy of George R. Schneider.

Power plant erected in 1920 on the Bayside Trail to serve coastal searchlights 5 and 6. Photo by U.S. Army Corps of Engineers, 1920. Photo courtesy of U.S. Army Corps of Engineers, Los Angeles District.