Historic California Posts, Camps, Stations and Airfields
Fort Baker: Battery Duncan
Battery Duncan
by Mr. Chuck Woffard
This Endicott battery was named in GO 194, February 14, l902 in honor of Colonel James Duncan, a West Point graduate, who had a highly distinguished record in the Mexican War. In 1849 he became a Colonel in the Inspector General Dept., but died that same year.

This battery was armed with two 8-inch breech loading rifles, Model 1888; serial number 8 came from the West Point Foundry and serial 24 from Bethlehem Iron Company. The guns each weighed 32,489 lbs and cost $16,875.00. There were a total of 93 manufactured.

These were mounted on barbette carriages Model 1892, numbers 2 and 4, and were fabricated at the Watertown Arsenal, and these are the specification for them. #2 was shipped from Watertown Arsenal to Fort Monroe on May 10, 1898, and from there to Fort Baker in 1899. Carriages Built: 9, Original Emplacement: 9, Time Emplaced: 1898-1900, Number of Bolts: 16, Circle Diameter: 9' 10", Parapet Height: 6". Most mounted in temporary emplacements, two designed batteries, Drew (1 emplacement) and Duncan (2 emplacements). The carriage weighted 84,000 lbs and cost $14,000.00.

The following is information on the Model 1888 #8 and #24

Emplacement #1 the reference height of the crest=214.01 and Emplacement #2 the reference height of the crest=214.04.

Gun # 1 Model 1888 Serial 8 was mounted and emplaced in April 1900, under the supervision of 1st Lt Harry Clark and was tested for level on May 10-12, 1900 by Capt. Otto von Geldru. Reference of base ring at the top of the ring = M.L.L.W. 212.14 ft. and the number of shots fired was 49, since its first target practice on January 5, 1904.

Gun # 2 Model 1888 Serial 24 was mounted and emplaced in April 1900, under the supervision of 1st Lt Harry Clark and was tested for level on May 10-12, 1900 By Capt. Otto von Geldru. Reference of the base ring/top of ring M.L.L.W. 212.9 ft, and the number of shots fired was 48, since its first target practice on January 5, 1904.

The following is information on Carriages Model 1892 #2 and #4

Carriage Model 1892 #2 was mounted May 10-12, 1900 under the supervision of 1st Lt Harry Clark and was leveled by Capt. Otto von Geldru.

Carriage Model 1892 #4 was mounted May 10-12, 1900 under the supervision of 1st Lt Harry Clark and was leveled by Capt. Otto von Geldru.

The sights on these guns were M1910, can not find the serial numbers for them.
Ammunition Service
The means which must be provided for moving ammunition depend, of course, upon the weight and bulk of the piece to be moved. Since this battery was a one story and was level from shell and powder rooms to the loading platforms, and used an overhead trolley to move the shells out of the room into the hall, where they were loaded on a shot truck and taken to the gun for loading, other than a crane to hoist the shell to the breech, in the powder there are no mechanical gear provided, the propellant charges were light enough to carry in a handbarrows.
The projectile are stored in rows along the wall of the shell room, with there point to the wall so the bases could be gotten at for placing fuses, the bottom layer of shells where placed in pairs and put on timber skids, and then stacked using the same method. There were trolley rails fastened to the ceilings over the center of gravity of the shells in each row, after 1908 this was changed, and the larger shells were stacked in two rows down the middle of the shell room, there fore there was a passageway between the walls and between the rows.
The form of trolley used in this battery were four wheeled travelers, running on the lower flanges of I-beams suspended from the ceiling of the shot room and passages. Each trolley carried a half ton Yale-Weston triplex block.
As far as powder service, the powder was shipped to the battery in metal cases and stored in racks, that they were shipped in, in most cases, there ends projecting into the passageway. When a cartridge was desired the solder strip was to be pulled of without moving the cartridge case from the rack, this loosens the top of the case and the cartridge is then pulled out, leaving the case still fastened in it proper place, all the powder was carried in a handbarrow, by four men to the gun for loading.
The ammunition supply for this battery was stored in the magazines. There were two shell rooms that where 27' x 10', and held 200 shots that were 28" long and 200 shell that were 36" long. The battle allowance for this battery was 150 rounds of fire and larger amounts could be put in the shell and powder, by stacking higher or closer together. The size of the powder magazine was 16' x 17' and held 800 cartons, 3 tiers high each box was 10 1/8 x 10 1/6 x 23 13/32, can not find out how many in a box, and each and had a range of 16,268 yards.
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. On March 17, 1898 directions were given by telegraph to construct this emplacement for two 8" guns with funds from the appropriation for National Defense Act of March 9, 1898, in the amount of $49,000.00.

Further instructions directed the use of all possible dispatch in carrying this work to a completion. Lt Deakyne was placed in charge, after surveys of the ground had been made and plans prepared work was commenced. This battery was arranged to straddle the ridge and face south, thus giving the most advantageous field of fire. This peculiar situation enabled the magazine, etc. to be held at the level of the terrepleins, so that no lifts are required and the service of the guns would be very rapid. There was some time consumed in building roads, arranging the pumping plant, and accumulating supplies. The road itself was 2,400 feet long, with a grade of 1 in 15 to connect the battery site. Construction of this battery began in March 29, 1898, with the clearing and grading of the site.

After the site was cleared, the excavation was started. There was 17,885 cubic yards of dirt and sand excavated . The material encountered was a soft red rock that required blasting and two shifts of men working from 4.00 a.m. until 12.00 p.m. and from 12 p.m. till 8.p.m. were employed in the excavating. Part of the work was done before and after daylight, light being obtained from large oil lamps, known as station lamps. Excavation for the magazine was carried down to grade by April 21, 1898 and the construction of forms was then begun. On the timber used in making the forms, in all cases dressed lumber was to be used. After the forms were started then came the iron and steel, in the form of I beams for reinforcing ceilings, and in columns for supporting ceilings. For reinforcing concrete deformed steel bars were inserted into places in the forms. A total of over 2,300 lbs of reinforcing bars was used.

While excavation was in progress the concrete plant was being put up. It consisted, essentially, of a cubic mixer driven by a steam engine and a large platform above the mixer. The material was hauled up to this platform by teams, and after measurement in the required proportions it was delivered through a hopper into the mixer. The mixer was given at least 10 turns; the concrete was then discharged into cars running on a track that extended from the mixer to all parts of the work.

The first concrete was laid April 24, but owing to difficulty in operating the original pumping plant, concrete work was not fairly started until May 4. The rough concrete of the magazine was completed May 12 and cement finishing was immediately begun. In the larger emplacement like Duncan the gun block is very large and complex, and separated from the other portions of the emplacement by "planes" or more "properly, surfaces of weakness", there is one between the parapet and also one between the loading platform, the latter is sometimes it is a few feet farther away from the axis of the gun, also there is the loading platforms, which is space around the gun and the carriage, upon which the members of the detachment stands while loading the ammunition the gun. By the 14th the rough concrete of platforms was in place, and the base rings have been set. There was used over 2,700 yards of concrete and nearly 1,112 yards of finished concrete, which they mixed in a color to help it blend in with top of the hill, was used in this battery.

A large amount of excavation was made in front of the battery to cut down the ridge to the necessary grade for the field of fire, at the end of June there was still a months on hand to entirely complete the work.

All walls in contact with earth were coated with paraffin paint. On smooth plastered surfaces 1 gallon covered 8 square yards with one coat or 6 square yards with two coats. The magazine was covered with an embankment of earth; in this a lookout was built. The walls and ceiling of the rooms and passages were whitewashed; using 1 barrel of lime, 1 bluing, 1 lb. of potash, and 10 lbs of Russian tallow.

The walls that show in the distance were tinted to correspond with the color of the soil bank surrounding the battery. For this purpose they were coated with a mixture of cement and water to the constituency of whitewash and adding Pecora mortar stain and lampblack in such proportion as to produce as nearly as possible the dull red color of the bank, and the results were satisfactory, both in immediate appearance and durability. The earth covering the magazine and the various slopes was coated with loam and seeded with barley.
A reservoir for permanent water supply of the battery was built on the ridge northwest of the battery. It is cylindrical in shape, 12 feet in diameter and 12 feet high, made of concrete, having its top on a level with the surface of the ground. Its capacity is about 10,000 gallons. The water is pumped to the reservoir from a well near Horseshoe Cove with the pumping plant that was used in the construction of the battery.
A latrine was constructed on the west side of the road leading out from the north corner of the battery. It consists of rear and end walls of concrete 1 foot thick, with a frame front and shingle roof. The water for the latrine comes from the reservoir supplying the battery, the outlet is a 4" pipe leading down the hill from the battery and emptying at the bluff near the edge of the bay.
The width across the front of this battery was 165' and the depth was 90', the gun had a range of 16,268 yards, at an elevation of 217 feet; distance between the guns 138 feet. Unlike most heavy-caliber batteries of this period, Duncan was a one story work, with its magazine floor at the same level as the emplacement, and a very high central traverse, it also had a Plotting Room (10' x 28') that was equipped with one Lewis Depression Position Finder, one Whistler Hearne Plotting Board: Model 1904, one Pratt Range Board: Model 1905, and Time Interval Ball, and E and D Room (10' x 10' ) Guard Room (10' x 16') and a switchboard, which was part of the E and D room with a central gallery (75' x 6') to take the shells and powder to the guns.
One of the last thing to be done is to the using of sand on the front and flanks of the battery. 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, there was over 3,000 yards of fill including the back fill. 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.
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, made an inspection of the structure, and all was in order the keys, were transferred to the Artillery commander. This two 8-inch gun emplacements on Yellow Bluff were completed in March 1899, the Engineers reported it complete and recommended that it be turned over to the care of troops even through the guns and carriages had not arrived. The carriages arrived in July from the east, and R.D. Noble and A. Desonza of Sausalito moved them from the wharf to the site of the battery for the sum of $585.00 and were completed in early 1899. On May 7, 1898, the engineers reported it complete and recommended that it be turned over to the care of the troops even though the gun had not been mounted.
The guns arrived Dec. 1899 and Davis & Sons of San Francisco moved them to the site for a cost of $420.00, the work was completed the same month. The base rings were set in January, the reference of Base Ring-Top LLW 212.14 feet, then the guns where mounted, and the battery was and transferred on May 6 1900, at a cost of $57,536.00.
Fire Control
The Plotting Room at Duncan had the following equipment in a 10' x 28' room that was equipped with one Lewis Depression Position Finder, Type A-Model 1 and the top of the pedestal was 4.35 -- one Whistler Hearne Plotting Board: Type A Model 1904, one Pratt Range Board: Model 1905, and Time Interval Ball. This battery had a standard B.C. and B station. No horizontal system provided. Standing fire control system installed and was complete in 1909.
It was ventilated by natural draft 6" vent from the magazine terminating in emplacement wall. It was connected to both water and sewer and had a siphon latrine, for data transmission they were provided a telephone and speaking tubes. Trunnion elevation in the inside of this battery was 215.1, Datum plane M.L.L.W.
It's guns were dismounted in 1917, and shipped to the Watervliet Arsenal, where they were mounted on railway carriages, these weapons were never sent overseas, but rather remained in storage for many years, the original barbette carriages were sold as scrap to the Union Junk Company of San Francisco in May or June of 1918, they also left much of the equipment and machinery in place. After the guns in this battery were dismounted, the magazines were used for storage purposes. In July 1, 1932 the latrine and the B. and the B.C. were demolished as per the authority if the 1st Ind HQ Ninth Corps. This battery saw service from 1898 to 1917. Battery Duncan offers a vivid contrast to the near by 1870s Battery Cavallo, and the 1900s Battery Yates, to the novice and the expert alike the contrasts in architecture and material among these three batteries can be an exciting experience.
Battery Duncan
by Justin Ruhge
Commenced immediately upon the receipt of funding, Duncan was built in about three months. The carriages arrived from the east in July 1899. The work was completed in December and the guns mounted shortly thereafter. The battery was turned over to the troop on May 5, 1900.
Located on Yellow Bluff above and to the northeast of Battery Cavallo, and known prior to its official naming as the Yellow Bluff Battery, Battery Duncan consisted of two 8-inch guns on barbette carriages, essentially identical with those at Battery Spencer, though smaller. Like the No. 3 gun of Spencer, its field of fire was directed inward, over the Bay. Both were designed at a time when coast defenses were intended not only to keep an enemy from entering a harbor, but also to deny him safe anchorage should he succeed in entering. Unlike most heavy caliber batteries of this period, Duncan was a one-story work with its magazine floor at the same level as the emplacements, and with a very high central traverse.
Battery Duncan's two 8-inch breech-loading rifles Model 1888, No 8, came from the West Point Foundry and No. 24 came from the Bethlehem Steel Company. These guns were mounted on barbette carriages Model 1892, Nos. 2 and 4 from the Watertown Arsenal.
Battery Duncan was names in General Order 16 February 14, 1902 in honor of Colonel James Duncan, a West Point graduate, who had a highly distinguished record in the Mexican War. In 1849 he became a Colonel in the Inspector General Department but died that same year.
Battery Duncan's first target practice by troops of the 68th Company, Coast Artillery was on January 5, 1904.
Because of the limited utility of both the battery's orientation and its weapons, it came to be regarded as obsolete by World War I. Its guns were removed after having fired a total of only about 50 rounds each and then used as railroad guns in Europe. Following its abandonment as an active defense unit, the battery structure was used, along with the old Battery Cavallo fting type of carriage. Later this plan was modified to place the guns on the Buffington-Crozier carriages.
Report of Completed Works - Seacoast Fortifications
Report of Completed Works - Seacoast Fortifications: Battery Duncan
Battery Duncan Today
Image courtesy of Mr Chuck Woffard
Additional Online Histories
Harbor Defenses of San Francisco - A Field Guide 1890 to 1950
Updated 14 January 2016