Historic California Posts, Camps, Stations and Airfields
Fort Winfield Scott: Batteries Stotsenburg and William McKinnon
 
 
 
Constructed as one battery in 1897, the work consisted of four pits in a straight line, each pit having four 12-inch, rifled, breech loaded mortars. Magazines and service rooms stood between the pits and were covered by earthen traverses. Called Mortar Battery 2 while underconstruction, it was formally named in honor of Captain John M. Stotsenburg, killed at Tingua, Luzon Phillipine Islands, in 1899. Later the number of mortars were reduced to eight and the battery divided for more efficient operation. Pits C and D became Battery William McKinnon in honor of Chaplain McKinnon who served with distinction in the Spanish American War and the Philippine Insurrection. In 1918, two mortars each were removed from Batterties Stotsenburg and McKinnon to arm Battery Walter Howe at Fort Funston. These batteries remained armed until 1943 when the mortars were removed and scrapped.
 
 
What are Seacoast Mortars?
 
Battleships and cruisers might have had more than a foot of armored plate on their sides, but their decks were reatively thin. Battery Alexander could exploit this weakness. Fired in groups, mortars hurled 700 pound projectiles in a high arc to drop onto the warships unprotected decks
 
 
 
 
 
 
Images courtesy of Mr. Chuck Wofford
 
 
Batteries Stotsenburg and William McKinnon
by Justin M. Ruhge

These two batteries were originally constructed as one battery in 1897. The structure consisted of four pits in a straight line; each pit had four 12-inch, rifled, breech loaded mortars for a total of 16 new model mortars. This battery was located southeast of Battery Crosby.

At Stotsenburg, three of the mortars were made at the Watervliet Arsenal, four at the Builders Iron Foundry and one at Niles Tool Works Company. The carriages were Model 1896 converted to1896 MI. All eight came from Southwark Foundry and Machine Company.

At McKinnon, three mortars came from Watervliet Arsenal, four came from Builders, and one came from Bethlehem Steel. The carriages were Model 1896 and all came from Robert Poole and Sons.

Magazines and service rooms stood between the pits and were covered with earthen traverses.

The Battery was named in honor Captain John M. Stotsenberg who was killed at Quingua, Luzon, Philippine Islands in 1899. Later, the number of mortars was reduced to eight and the battery divided for more efficient operation. Two of the pits were designated Battery William McKinnon in honor of Chaplain McKinnon who served with distinction in the Spanish-American War and the Filipino Insurrection and died on September 25, 1902.

 

Model 1890 Mortar on M1896 Carriage

 

Batteries Stotsenburg and William McKinnon
by Chuck Wofford
 
Named in G.O.16, February 15 1902, in honor of Capt John Stotsenburg, Sixth Cavalry who was killed in action in the Philippine Islands in February 14th 1899, formerly Colonel of the 1st Nebraska Volunteer Infantry, who was killed in action at Quinqua, Luzon, Philippine Island on April 23rd 1899. Graduated from West Point 1881. 2nd Lieutenant 6th Cavalry, 11th June 1881, 1st Lieutenant 19th August 1889, Captain 14th December 1898. Graduate of the Infantry and Cavalry School, 1897. Major 1st Nebraska Volunteers, 9th May 1898. Born in Indiana. Appointed from Indiana. In G.O. 20 January 20 1906, in honor Chaplain William McKinnon 3rd Third cavalry, who served with distinction in the Spanish American War and the Filipino insurrection in the Philippine Island and who died September 25, 1902. Born in Massachusetts. Appointed from California. Stotsenberg was Pits A and B and McKinnon Pits C and D.
 
Ordnance
 
Battery Stotsenberg was armed with 8 mortars, 4 mortars in each of two pits. All the mortars for Stotsenberg were model 1890 M1. Pit A=nos 22, 33, 47, 35, Pit B=31, 30, 49, 6 and # 47, 35, 49, were manufactured in 1998 at the Watervliet Arsenal. # 22, 33, 31, 30 were manufactured in 1898 at Builders Iron Foundry and #6 was manufactured 1898 at Nile's Tool Works. Battery McKinnon was also armed with 8 mortars, 4 in each of two pits. All the mortars in Battery McKinnon were all model # 1890 M1. Pit A= nos 34, 36, 23, 28-c. and # 34, 36, 23 were manufactured by Builders Iron Foundry, # 28, was manufactured by Watervliet Arsenal. Pit B= nos 39, 46, 28-d, 22-b. and # 46, 39 were manufactured at Watervliet Arsenal, # 22 was manufactured by Bethlehem Steel Company, #28-b was manufactured by Builders Iron Foundry. ModelM1 # 22-b-23-28-c-46, were transferred to Battery Walter Howe, Fort Funston, per approval of the Secretary of War 10 February 1917, G.O. # 660.2-20, of plan proposed by for defense of the Golden Gate and adjacent waters. There was 185' between the centers of the guns from pit to pit, and 10' between gun in each pit. The cost of the mortar was $7,750.00, and the weight of the mortar is 29,120 lbs. These mortars had a range of 15,000 yards.
 
Battery Stotsenberg had 8 carriages, Model 1896 converted to 1896M1, and were nos 60,61, 62, 63, 64, 65, 66 and 67, and were all manufactured by Southwark Foundry and Machine Company in 1898. Battery McKinnon had the same amount until Feb. 10 1917 when four of them were moved to Battery Howe at Fort Funston. There numbers were Model 1896M1, # 79, 80, 85, 86, 91, 94, 95, and 96, and all were manufactured at Robert Poole and Sons Company. There were 310 built, and were emplaced from 1897 to 1921, there various reallocations and partial removals from 1917 to 1921. The Carriage weighted 236,00 lbs, and the cost of the carriage was $12,500.00.
 
Ammunition Service
 
The powder rooms of which there were 4 were 41' X 11'and 9' high and had a capacity of 800 rounds each, and the Shell and Shot Gallery, which there were also 4, were 105 ' x 11' x 9 and were located in the middle of pit A & B and had a capacity of 800 rounds and C & D, had a capacity of 800 rounds. In the shell and shot and powder rooms in this battery there were no need for elevators or ammo hoists. Shells were brought from the magazines to the main hall via overhead chain hoist or trolley. The projectile weighted 1046 lbs and the propel weighted 60 lbs. The form of a trolley used in this battery was a simple I beam attached to the ceiling by bolts through an upper flange, this form consisted of a pair of wheels running on the lower flange on either side of the beam and held together by a U-shaped yoke hanging down under the beam, this type of trolley systems consisting merely of a single line of rail or of simple loops for moving the heavy shells. It also had two powder rooms which were 10 X 47 or 470 sq. ft each , with a small 10 X 18 room between the two powder magazines. There were small rail cars that carried the silken bags of gun powder out to the guns, there is an interesting turntable at the T in the powder room, where the rail cars could be turned, it also had tracks in the floor, and then taken to the front of the battery for the gun crews. This was about the same design in all the mortar batteries in the S.F.H.D. War Reserve for this battery was, 480 for each 2 pits, and the battle allowance for this battery was, 480 rounds of fire, this battery could hold up to 1470 projectile, 500 powder charges for which storage space is provided for in the main powder magazine is 200 per mortar.
 
Sub-Caliber
 
This battery had 75 mm sub caliber tubes for 12 inch mortars, and used 18" projectiles.

Construction
 
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. In June 14 1897 the engineers were informed that and allotment of $108.000.00 was made for the construction of this battery, located south of Rob Hill. Work has begun and will be pushed as actively as possible so as to get the heavy work done before the winter rains start. This battery was 850' across and 175' deep, beside the Shell and Powder Rooms, there also was Guard Room that was 12' X 19' an Engine Room that was 12' X 19' and two Store Room that was 12' X 19' and 12' X 41' A Tool Room that was 6' X 7' and part of it was 6' X 20'. There were two Plotting one on each end of the battery, they were 12' X 19', also there were three Shot Gallery, and were 11' X 115' and there were 3 Powder Gallery, that were 8' X 115'
 
The work on this battery commenced July 6 1897 with the clearing of the site and laying out the work at a cost of $266.25. As large force of men and teams were put on the as could be worked to advantage, and all construction worked hurried with a view to completing it before the fall rains began. The clearing of the site was the only thing done in the last fiscal year of 1897.
 
On July 1 1898 preliminary work such as the building of roads etc. was commenced, and was continued until July 6 1898, the day the excavation was commenced
 
There was 43,500 yd of dirt and sand removed , the main part excavation was in sand, but near the bottom of the cut a stratum of clay was met. This consisted of a heavy dark blue almost black material, exceedingly difficult to work: in fact, it was found impossible to work it only by cutting it out with mattocks and axes. The stratum reached a height of about 10 feet above the foundation at the right end of the magazine # 1 and from that height sloped gradually, running to nothing at the front and left of the battery foundation. A small of rock too was met with in the excavation for guardroom #1. It is probable that the actual amount of material was far in excess of the estimate, because of the fact that the sand would stand at only a very gradual slope, neccessitating the removal of a great amount not originally reckoned upon. This fact together with a very long and high haul of material, resulting from the extremely large quality of earth to be handled made the cost of excavation larger that estimated, which was $22,411.91.
 
In September the excavation has progressed so far that the first step is to put in a foundation, so far as we are concerned a gun emplacement is nothing more or less than a masonry structure, and exactly the same precaution should be applied in constructing the foundation of a gun emplacement, as would be considered necessary in constructing the foundation of any heavy masonry structure. The foundation for the magazine could be laid. at this time. In the meantime the construction for the framework for magazines and passages was going on, on the timber used in making the forms, in all cases dressed lumber, also the wood forms will be kept wet for the time to cure the new concrete, and care use in removing the forms, when the curing is finished, The forms for this battery cost $6,738.08. The reinforcing steel was measured by the pound in place and ready for pouring concrete and will include allowance for minimum laps, splices and hooks, if any item needs to be embedded in the concrete such as bolts, anchor, pipes or one things that was necessary to mount the mortar in the emplacement, were Maneuvering Ring, it was found in the first batteries, there were no arrangements to attached the block and tackle, to move the carriages and the mortars in the emplacement. and other embedded items are firmly and securely fastened in place indicated on the plans, and they should be clean and free from rust, scale, oil, or other foreign matters. Construction of this battery started immediately after placement, the concrete shall be properly forked back along the faces of all the forms by the use of a standard concrete forks or spades. Also used in the batteries were Iron and Steel, in the form of I beams for reinforcing ceilings, and in columns for supporting ceilings, for reinforcing concrete. Concreting of the four magazines was completed by November 1998.
 
The concrete work on platforms of Pit # 4 was finished during September, In October platforms of pits # 1 and # 2 were constructed, as also was the #4 guardroom. In this month the first base ring was set in pit #1. The concrete put in up to this time was all hand mixed. By the 27th forms for magazines #3 and # 4 were up and the concrete mixer and approaches thereto were completed, and the making of concrete by machine commenced on that day. The plant was probably more perfectly installed that it had every been before on the work here. This was possible without incurring great expense, mainly because of the great height that the mound resulting from excavation reached. The road that had been used in the excavation was somewhat improved, so that the material to be used could easily be hauled over it to the mixer. This later occupied a position between the site of the battery and the mound resulting from material excavated From the road above referred to it was then necessary to construct approaches to the mixer. The additional height enabled the use of gravity supply through out in furnishing the material to the mixer, and it was in continuous operation reaching a production of 200 barrels per eight hours shift and over 11,920 cubic yd were used, not counting the sidewalks, and the finishing concrete. The concrete work on magazine 3 and 4 was finished November 16 1898 ; on the 10th the forms for magazines 1 and 2 were up and concreting was commenced being completed on the 19th. The mortar platforms of pit 3 and guardroom 4 were built during the month, handmade concrete being used. The retaining walls around the pits were built as quickly as the forms could be put up. The setting of the base rings was continued as they were received.
 
On the 26th of November the forms for the administration building were up and by the end of the month nearly all the concrete was in.
 
On the 17th back filling was commenced over the guard rooms at the end of the battery and continued until completed, there was 45,850 cubic yd of backfill used at a cost of 10,545.13.
In the meantime the mixing plant was taken down and back fill over the magazines and administration building begun, and was completed Feb. 12 1898. The 12th of February marks the date of the practical completion of this battery. All the work hat remained after that date was that of finishing up and this was done as expeditiously as the condition permitted. The sewerage system of the battery is complete, two large latrines for the enlisted men d one for the officers.
 
One of the last things to do, 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, (Horizontal protection, front of magazine, 15 feet of concrete, 45 feet of sand; equivalent to 30 feet of concrete. - Horizontal protection in front of the Mortars, 15 feet of concrete, 40 feet of sand; equivalent to about 28 1/2 feet of concrete.
The last base ring was set in March; the carriages except the first were mounted by the Artillery, with the assistance of the Engineering Dept hauling parts to the pits. As of this date there have not been received any Mortars. When the structure is completed the district Engineer officer prepares the "transfer drawing" then the Engineer officer and the local Coast Artillery officer, make an inspection of the structure, and all was in order, the keys, were transferred to the Artillery commander. It was finished in 1898, and transferred on April 27 1900 at a cost of $180,188.49.
 
Power
 
The battery required 11.6 kw for lights and had one 20-HP Hornsby-Akroyd horizontal oil engine; De La Vergne Co; purchased February 19 1899. One 12.5-KW, 125 volt direct current , multi-polar, belted dynamo; Bullock Electric Co; purchased February 19 1899. The e cost for this plant was $3,740.86 and was transferred to the Artillery April 21. 1900.
 
Miscellaneous
 
The Trunnion elevation in floor of pit 338.6, Datum M.L.L.W.
 
The battery center is a concrete block with a copper bolt center set with ground in small knoll 127 feet distant from B4' 6" from the Battery, points in pits are marked by a cross in the top of a copper bolt set flush with the concrete; the Battery centers are marked in the top of a copper bolt set in a block of concrete flush the surface of the ground, there are on the superior slopes three monuments consist of a copper bolt set in a pipe filled with concrete, the top being flush with the surface of the ground and the center being marked by a cross in the bolt.
 
The Azimuth from each station to a common reference point for this battery, The Azimuth "A" pit center to "B" center 72� 55 1/4". The distance from "A" center to "B" center is 58.46 yd.; Azimuth F�5 to center of "A" pit is 276. �94. The last of the base rings were set in March and the artillerymen mounted the carriages.
 
It was also connected to water and sewer, and had siphon latrine, for ventilation it used natural draft, 6" terra cotta vents from the magazine terminating on top of fill in sewer pipe.
 
Fire Control
 
The fire control for this battery had the following stations. There was a B/13 on Rob Hill, which housed the Battery Commander's Station, the Plotting Room, and the Primary for B/13. This was constructed in June 1910, and had a limited azimuths of a field of view of station: 230.25o to the right and 8.60o. The height above M.L.L.W. of top concrete pedestal; 383.704 feet-- Height of axes of Tel of inst. above concrete pedestal; 4.396 feet--Height of axes of Tel of inst. above M.L.L.W. Pedestal 388.100 feet. There was a B/13 at Fort Point, which used for Secondary for B/13-B/13--Secondary for B/13-B/13-Primary for B 1/13-B 1/13. They were constructed in June 1910, and had a limited azimuths of a field of view of station: 50.00o to 149.75o, and 185.75o to 275.15o. The height above M.L.L.W. of top concrete pedestal; 77.004 feet-- Height of axes of Tel of inst. above concrete pedestal; 4.396 feet--Height of axes of Tel of inst. above M.L.L.W. Pedestal 01.400 feet.. There was a B 1/13 at Baker Beach, which used Primary for B 1/13 - B 1/13 and Battery Commander's Station during high tide, it was constructed in December 1910, and had a limited azimuths of a field of view of station: 78.05o to 176.62o. The height above M.L.L.W. of top concrete pedestal; 35.604 feet-- Height of axes of Tel of inst. above concrete pedestal; 4.396 feet--Height of axes of Tel of inst. above M.L.L.W. Pedestal 40.000 feet.- There was a B-4 on the right flank of Battery Blaney which was used as a secondary for B 1/13- B 1/13 and was constructed in June 1910. It had a limited azimuths of a field of view of station: 148.48o to 257.62o. The height above M.L.L.W. of top concrete pedestal; 75.804 feet-- Height of axes of Tel of inst. above concrete pedestal; 4.396 feet--Height of axes of Tel of inst. above M.L.L.W. Pedestal 80,200 feet, also there was a E 1/13 about 82 yards south of B 1/13- B 1/13 and was constructed in 1916 and was used in case of emergency. Consists of concrete pedestal for Azimuth instrument the open, with limiting azimuth of field of view of station in the open.. There was a second E 1/13 about 18 yds north of B 1/13 which was constructed in 1916 to replace B 1/13 in case of emergency, and consists of concrete pedestal for Azimuth instrument in the open, with limiting azimuth of field of view of station in the open.. The plotting room had the following equipment: 1 Plotting Board, Model 1906 # 23- 1 Plotting Board, model 1906, #55, 1 Plotting Board, model 1906 #5-1 Deflection Board, model 1906 #38- 3 Cover canvas for Plotting Board- 1 Deflection Scales #31- 1 Set Forward Ruler, model 1907,#51.
 
After this battery was split into two batteries, there were some changes in the fire control, and a new plotting room was added for Battery McKinnon
 
The fire control for this battery had the following stations, on Rob Hill which housed the Battery Commander's Station, the Plotting Room, and the Primary for B/13. This was constructed in August 16 1908, and had a limited azimuths of a field of view of station, Left 66.47o to the right and 167.47o. The height above M.L.L.W. of top concrete pedestal; 388.1 ft-- Height of axes of Tel of inst. above concrete pedestal; 392.48 ft. And a field of view of station, Left 48 to the right and 276. The height above M.L.L.W. of top concrete pedestal; 76.014 ft-- Height of axes of Tel of inst. above concrete pedestal; 80.4 ft.. There was a Observation post, located near Baker Beach, date of construction 1907-1908, and had a limited azimuths of a field of view of station: to left 62.70 to right 180.00, The height above M.L.L.W. of top concrete pedestal; 40.00 feet-- Height of axes of Tel of inst. above concrete pedestal; 45.614 feet--on the right flank of Battery Blaney which was used as a secondary for B and was constructed in June 1908. It had a limited azimuths of a field of view of station: 148.48o to 257.62o. The height above M.L.L.W. of top concrete pedestal; 75.804 feet-- Height of axes of Tel of inst. above concrete pedestal; 4.396 feet--Height of axes of Tel of inst. above M.L.L.W. Pedestal 80,200 feet, also there was a E 1/13 about 82 yards south of B 1/13- B 1/13 and was constructed in 1916 and was used in case of emergency. Consists of concrete pedestal for Azimuth instrument the open, with limiting azimuth of field of view of station in the open. There was a second E 1/13 about 18 yds north of B 1/13 which was constructed in 1916 to replace B 1/13 in case of emergency, and consists of concrete pedestal for Azimuth instrument in the open, with limiting azimuth of field of view of station in the open. The plotting room had the following equipment: 1 Plotting Board, # 22- 1 Mortar Deflection Board#36 -- 1 Cover canvas for Plotting Board- 1 Deflection Scales #31- 1 Set Forward Ruler, model 1907,#51. Also there was a B station constructed 1907-1908 with a limited field of view of 128o-254o. The height above M.L.L.W. of top concrete pedestal; 75.814 feet-- Height of axes of Tel of inst. above concrete pedestal; 82.5 feet- Note - This station is not a present in the hands of the battery, althrought is part of the approved installation for the battery. It is useful only for firing inside the harbor or for land firing and requires additional plotting board to accommodate the base line B"-B"
 
Abandonment
 
The battery called Mortar Battery No 2 while under construction, and then was named Battery Stotenburg/McKinnon. These battery were split on January 25 1906. These batteries saw service from 1900 to 1943. Four mortars were transferred to Battery Howe, Fort Funston from Battery McKinnon Serial Number 22, 23, 28, 46, per approval of t Secretary of War, Feb. 10 1917, of plan proposed by the Commanding General, Pacific Coast Artillery District for a plan for defense of the Golden Gate and adjacent water (P.C.A.D.). There was a letter dated February 15 1937 announced these batteries abandoned, and was signed by Cyrus Shelton. In the late 1930, these mortars were to go to other forts, but other that the four that were emplaced in Fort Funston, the balance were not moved.
 
Loading at M1890 Mortar. Pre-World War I (Presidio Army Museum Collection, Golden Gate National Recreation Area)
 
 
Lock and Breech Block of the M1890 Seacoast Mortar (Presidio Army Museum Collection, Golden Gate National Recreation Area)
 
 
 
Reports of Completed Works - Seacoast Fortifications
 
 
 
Reports of Completed Works - Seacoast Fortifications: Batteries Stotsenburg and William McKinnon
 
Battery Stotsenburg circa pre-World War I (Presidio Army Museum, Golden Gate National Recreational Area)
 
A M-1890 Mortar being fired from Battery Stotsenburg's Pit A. Circa pre-World War I. (Presidio Army Museum Collection, Golden Gate National Recreation Area)

 

 
Battery Stotsenburg Today
 
Battery Stotensburg's Pit B, (October 2000)
 
Pit A (October 2000)
 
 
Battery McKinnonToday
 
Pit A (October 2000)
 
 
 
Other Online Histories
 
FortWiki
Battery William McKinnon
Battery Stotsenburg
National Park Service
Harbor Defenses of San Francisco - A Field Guide 1890 to 1950
 
 
 
 
 
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Updated 23 June 2017