Historic California Posts, Camps, Stations and Airfields
Fort Barry: Battery Patrick O'Rorke
Battery O'Rorke during World War II
Battery O'Rorke was built to mount four 15-pounder, 3 inch guns, serial numbered 90, 91, 92 and 94, on Model 1903 pedestal mounts. The mounts were built by the Watertown Arsenal and were serial numbered 68 through 71. It was not armed for many years, at least not until 1909. The battery was nevertheless named by War Department General Order 194 on December 27, 1904 in honor of Colonel Patrick Henry O'Rorke. Colonel O'Rorke, at native of Ireland and a graduate of the U.S. Military Academy at West Point, was killed at the age of 27 at the Battle of Gettysburg during the Civil War in July 1863.
Each gun could fire shells weighing 15 pounds a distance of five miles. These small guns were important because they could be loaded and fired more rapidly than larger weapons. The guns were located at their location to prevent enemy landings on Rodeo Beach.
The battery was inactivated in 1945 and its guns scrapped in 1946.
Battery Patrick O'Rorke
by Justin Rughe

Battery Patrick O'Rorke consisted of four 3-inch, 15-pounder breech-loading rifles. The guns were mounted on barbette carriages Model 1903, Nos. 68-71 manufactured by the Watertown Arsenal. Work began in January 1902. The guns were placed 29 feet apart. The battery was located at an elevation of 199 feet. Construction costs were about $30,000. The battery was transferred to the troops on June 8, 1905.
The battery was named in General Order 194, December 27, 1904, in honor of Colonel Patrick Henry O'Rorke, born in Ireland and a West Point graduate, who was killed at the battle of Gettysburg, Pennsylvania in July 1863.
The guns were removed after World War II in 1946.
Battery Patrick O'Rorke
by Chuck Wofford
This battery was named in GO 194, December 27 1904 in honor for Patrick J. O'Rorke who was born in Ireland and a West Point graduate, who was killed at the battle of Gettysburg Pennsylvania in July 1863. He was in the 140th New York Volunteers (1st Lieutenant Corps of Engineers).
This battery was mounted with four 3-inch guns (15 ponder), Watervliet Arsenal, Model 1903 nos 90, 91, 92, 94 the cost of the guns was $3,165.00 and weight of the gun was 2690. The elevation of this, from the battery was 199 feet, with 29 feet between the guns. The following are the specification for these guns.

These guns were mounted on pedestal barbette carriages, Model 1903, # 68, 69, 70, 71, from the Watertown Arsenal. The Carriage for this gun had a Maximum elevation of 16 degrees, Minimum elevation was, 10 degrees.
There were 107 built, Original Emplacemewnt:79 US, 22 Err, Time Emplaced 104-1917, relocation until 1942. There was 12 bolts, 14 on rare occasions, Circle Diameter 3'1", Parapet Height: 3', Center - tap - Parapet variable. Note even distribution of 12 bolts, often with center pipe for electrical conduit. The carriage weighted 3,310 lbs with an elevation of 16 degrees, and the cost of the carriage was $4,250.00. The electric wiring and setting the pedestals, was completed May 1905. The guns did not arrive in San Francisco until late in 1909. The following are the specification for these carriages.
The following is information on the gun Model 1902 # 90, 91, 92, 94
h and every step of the ammunition service may be performed with such speed that the ammunition can be carried to the breech of the gun at least as rapidly as it can be loaded into the gun and fired. This gun being 3-inch, the projectiles are ordinarily stored and transported to the gun in the form of complete cartridges , put up in a metallic case much like a cartridge used in a Infantry rifle, theses cartridge weigh so little that they can be moved by hand, with out any mechanical handling, the 3-inch, is always issued to the battery, and shipped to the battery in wooden boxes or cases containing several rounds.(complete rounds without packing weighted 26.70 lbs or 4 rounds packed in a box weighted 166.8 lbs and were 3.66 cubic feet, the box s were 43 X 12 1/6 X 12 2/8, in inches, or 61.92 cubic inches. Fixed rounds of ammunition for these guns are packed moisture-resistant fiber containers in wooden packing boxes, or without individual containers in sealed metal lined wooden packing boxes. While the weight of the individual rounds varies somewhat, dependent upon type and model, the above following data are considered representative for estimating weight and volume requirements. It is kept in the form that it was received until just before it is to be used, when the boxes are broken open. Its storage, therefore consist simply in piling up the boxes in the most convenient arrangement, about 6 boxes high, so they were easy to get down, The projectile are stored in rows along the wall of the shell room. The ammunition supply for this battery was stored in the 4 magazine that were 9'' X 15' and were on the lower floor of the guns batteries, and each held 1600 rounds. The battle allowance for this battery was 1600 rounds of fire. The War reserve for this battery was 1600 and 200 H.E. at the central reserve, at Fort Winfield Scott held 800.
Model M-1903
As with any battery is to be built in any Engineer district, as much information as may be necessary is sent to the district officer. Construction of this battery was authorized in 1903, the clearing and grading of the site, so that the excavation could start this took about 6 days using horse drawn scrappers. When this work was finished, the excavation started with the approximately removal of 15500 cu ft dirt and sand.
As the work proceeded the forms were started most of the forms had been built by this time, on the timber used in making the forms, in all cases dressed lumber were used. At this time before the pouring of the concrete all of the Iron and Steel, in the form of I beams for reinforcing ceilings, and in columns for supporting ceilings, for reinforcing concrete, they used deformed steel bars, this is emplaced before the pouring of the concrete, and there was over 24950 lbs of reinforcement used in this battery.
At this time every thing was ready to start pouring the concrete, "the battery was divided into several monoliths of different dimensions, the planes of junctions of these being where settlement would naturally first be noticed. One of these contiguous faces of two adjoining monoliths was plastered and then be painted." There was used in this battery, 6500 cu ft of concrete, 7500 cu ft of finished concrete. Generally the gun block, was the first to be poured, which is the portion of the emplacement that supports the gun and the carriage. Its size and mass therefore must such as to make it safe from overturning by the shock of the discharge, the size and shape of the gun block must, of course be such as to fit the carriage and consequently, it must be largely designed to accord with the Ordnance Dept drawing of the carriage, in fact for a few details such as drainage, bringing in the electric cable, ect the Engineer Dept in preparing gun block design, has but little freedom or responsibility".
One of the last things to finish the battery is the using of sand on the front and flanks of the lower floor of batteries, the sand was filled in front of the concrete, then when a shell was fired at the battery it has been found that a projectile entering a mass of sand appears to have a tendency to deflect upward and to leave the sand with out penetrating very far, the exception is the blast apron, which is made of concrete, and immediately in front of the gun, they had to be laid very carefully, or the would be blown away, there was over 11500 cu ft of fill used.
The drainage of this battery has had every precaution was taken to guard against leaking and to insure dry rooms. Ample drainage was placed throughout the battery and around the foot of the wall next to the earth fill. These walls were paint and plastered with paraffin, and a course of rock carried up between them and the earth to insure rapid drainage of any water on the face of the wall. The rear slopes of the battery were furnished with drains to intercept surface water flowing towards the emplacement. There were no partition tiles placed in this battery. A damp-proof course was carried entirely over the monolith containing the magazine, which consisted of a cement finished surface painted with paraffin and covered with rock draining to gutters slopping towards the from of the battery, where openings were left against the dry wall of rock between the earth fill and the concrete. Also a lead flashing was the entire length of the joint, near the surface to prevent leakage".
This battery was 144' across, and 45' deep, there were 4 Magazines that were 9'' X 15' -a C. R. F. Station that was 10'X 10'--and an Oil Room that was 10' X 8' and an Guard Room that was 8' X 15' and a B.C. that was 7' X 7', This battery was provided with an open crow's nest, B.C. station and an open C.R.F. station. There was no plotting room in this battery.
When the structure is completed the district Engineer officer prepares the so called "transfer drawing" then the Engineer officer and the local Coast Artillery officer, make an inspection of the structure, and all was in order and the keys, were transferred to the Artillery commander. This battery was completed in, 1904 and transferred on June 8 1905, at a cost of $69,193.64.
As far as the electrical power for this battery it came from Battery Guthrie/Smith plant. On 6/23/42 Plans for furnishing AC commercial power for lighting this battery was approved (675.1 SF), at a cost of $13,445.00.
This battery was hooked up to sewer and water, with a siphon latrine, and a telephone for date transmission, ventilation was by natural draft, 6" flues from magazines terminating at rear wall. Traverse in Azimuth in Emplacement #1/2/3/4, Left - 300, Right - 167. The trunnion in the battery was 198.9, Datum plane M.L.L.W. Also a letter dated Dec. 17 1941 to the Division Engineer a cost for camouflage material for this battery, and was ok'ed by General Stockton in Jan of 1942. This battery was assigned to Tactical Organization, Group 2.
This battery saw duty from 1909 until after WWII, and was to be used in the planned defenses of San Francisco. Under most conditions this small battery is overlooked by most visitors, it did however play a very important role in the history of the fortifications at Fort Barry, both for it different, and because of it location within an area inhabited by several batteries of different kinds and different eras. This battery is in good shape today and well worth a visit.

Additional Online and Printed Histories
Harbor Defenses of San Francisco - A Field Guide 1890 to 1950
Report of Completed Works - Seacoast Fortifications
Report of Completed Works - Seacoast Fortifications for Battery O'Rourke and associated structures.
Battery O'Rorke, Circa October 2000
Battery O'Rorke looking from Battery Edwin Guthrie in October 2000. Fort Cronkhite is in the background.
Looking toward Battery Edwin Guthrie. October 2000.
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Updated 23 June 2017