The illustration that accompanies this article is a watercolor that was recently offered up for bid on an eBay auction. Unfortunately, I was an unsuccessful bidder. However, I did download the image.
The caption for the painting, “The Prose and Poetry of Fortress Monroe, Va.,” established the location of the cannon in question. The image was one in a portfolio of late 19th-century watercolors painted by an artist named Gil, who painted extensively along the East Coast of the United States. I was impressed by the enormous size of the Rodman smoothbore and decided to investigate this interesting painting further.
Using an engineer’s scale and dividers I found the image of the woman in the painting to be 2.4 inches high. The vertical diameter of the cannon’s breech ring was 1.9 inches. There is no foreshortening along this axis. Assuming the woman to have been of average height, 5 feet 6 inches, I set up a ratio between the image dimensions and real dimensions and determined that the actual diameter of the breech ring was 52.2 inches.
When I used heights of 5 feet 5 inches and 5 feet 7 inches for the woman, the ratios yielded ring diameters of 51.4 and 53.0 inches. In my calculations I may have overlooked the fact that the lady could have been wearing heels!
I then consulted the book The Big Guns by Olmstead, Stark and Tucker. The diameter of the breech ring of a 15-inch Rodman was given as 41.5 inches. On the other hand, the same dimension for the 20-inch Rodman is 55.4 inches. I then assumed that the piece was a 15-inch Rodman and worked out the ratio in reverse.
The woman would have stood 4 feet 5 inches tall, a rather unlikely circumstance. Therefore, this was the image of a 20-inch Rodman smoothbore located at Fort Monroe, one of three monster Rodman cannons cast during or just after the Civil War. [Editor’s Note: Fort Monroe, not Fortress, is the correct name.]
Casting the Great Gun
The first of these behemoths that was cast is located outside the main gate to the Fort Hamilton Military Reservation in Brooklyn, N.Y. The piece was acquired by the Borough of Brooklyn by a Congressional act of 1900.
The muzzle face bears the following inscription: “No. 1, FORT PITT, PA., S.C.L. [Stephen Carr Lyford, Ordnance Officer Inspecting, 1863-65], 1864, 116497 lbs.” The right rimbase bears the foundry number “2053.”
The Scientific American issue of Feb. 27, 1864, carries two on-site reports of the casting of this piece at the Fort Pitt Foundry in Pittsburgh, Pa. One report was composed by a staff writer for The Scientific American. The other “official” report was sent by R. Auctick U.S.N., Assistant Chief, Bureau of Ordnance, to his superior, Commander H.A. Wise, U.S.N. Chief of the Bureau of Ordnance. There are some minor disagreements in these two reports as to the actual date of the casting. One report gives Feb. 4 as the date and the other Feb. 11. I’ll paraphrase the report of the Assistant Chief of Ordnance.
On Feb. 3 preparations for casting were completed. The flask and its mould were in the pit. The water-cooled core that was used in the Rodman process to create the bore and also cause the compression of the outer layers of iron upon the inner was positioned in the center of the mould, a very crucial task.
At 5 a.m. on the following day five “reverberatory air furnaces,” today we would know them as open-hearth furnaces, which had been charged with 105 tons of “Juniata” iron, a somewhat refined type of ‘pig iron,’ were put into operation. Three primary furnaces held 85 tons of iron and two smaller backup furnaces held 20 tons in case of need.
The primary furnaces were tapped shortly after noon and the molten iron flowed into a common reservoir. From here the molten metal was led to the mould. It took approximately 25 minutes to fill the mould with 170,000 pounds (85 tons) of molten metal.
After a two-week period of slow cooling, the mould was stripped from the casting. The bore was trued and machined to the proper size. The casting was placed in a lathe, which itself weighed over 200,000 pounds, and the exterior was turned down and smoothed.
The weight of the tube had now been reduced to 116,500 pounds, 58.5 tons (an M-1 Abrams Main Battle Tank weighs 60 tons). The length of the tube was 20-1/4 feet with a maximum diameter of 64 inches. The price of the piece charged to the government was $32,781.37.
Test Firings at Fort Hamilton
An 1892 plan of Fort Hamilton shows a single gun emplacement for a 20-inch Rodman mounted on a hydraulic buffer carriage, with a 7- inch pintle in what was referred to as the “New Battery.” There is a photograph in Miller’s Photographic History of the Civil War, Vol. 5, Page 137, which purports to be an image of the “20-inch Monster.”
Once again dividers and a scale indicate that this is actually a photograph of a 15-inch Rodman mounted on some type of reinforced carriage. The soldier in the photo standing on the chassis could not have gazed across the top of a 20-inch Rodman, not with its 66-inch maximum diameter!
The accompanying text in Miller’s does, however, contain information on the test firings of the giant Rodman. The 20-inch solid shot weighed 1,080 pounds and the spherical shell weighed 700 pounds. Shortly after being mounted the piece was fired four times with 50-, 75-, 100- and 125-pound charges. In March of 1867 it was again fired with charges of 125, 150, 175 and 200 pounds of powder. At an elevation of 25 degrees a range of 4-1/2 miles, was obtained.
These were the guns that established the International “Three Mile Limit” for Territorial Waters. In the 19th and early 20th century a nation “owned” those waters that it could defend with cannon fire.
This piece is extant. In 1903 the cannon was declared surplus property by the federal government and was given to the Borough of Brooklyn. It can be viewed at the Fort Hamilton military complex.
The Fort Hancock Gun
The second of these huge cannon was cast shortly after the close of the Civil War and can now be seen at the Sandy Hook National Park Site in New Jersey. The muzzle face bears the following inscription: “NO. 2, KFPF PA., [Knap’s Fort Pitt Foundry, Pittsburgh, Pa.] J.A.K, [John Alexander Kress, Ordnance Officer Inspecting, 1867-69], 1869, 115100 lbs.” The right rimbase bears the foundry number “3387.”
After casting and proofing, this piece was sent to the Coast Artillery facilities at Fort Monroe, Hampton Roads, Virginia, for testing. The piece remained there until 1876 when the United States Ordnance Corps decided to display the cannon at the Philadelphia International Exhibition.
Lt. Henry Metcalf, responsible for arranging the display, provides in his July 25 report to the Chief of Ordnance, some insight into the logistics involved in transporting these heavy pieces of artillery.
A schooner of 94 tons burden was chartered and sent to Fort Monroe. There she loaded the Rodman and a 13-inch seacoast mortar as deck cargo. Including timbers for blocking and beds, the load was estimated at 80 tons.
On passage north through Chesapeake Bay the old “bucket” nearly foundered in a gale. The schooner arrived in Philadelphia leaking badly, with her decks only 8 inches above the water. It must have been a “pump or swim” trip. Upon arrival at the wharf the vessel’s deck was 4 feet below the berm.
Through slow lifting by a steam crane equipped with an 11-inch hawser, and the judicious use of blocking, the monster was brought level with the wharf. The crane, with the aid of a locomotive, was able to inch the piece onto a flat car for its trip to the exhibition grounds. The offloading commenced at 4 p.m. on Friday and the piece was placed on the railway car on Sunday at 8 p.m.
In 1874 Sandy Hook became the site of the U.S. Ordnance Proving Grounds. Here were tested the converted Rodman rifles of the post- Civil War era and the early breechloaders of the Endicott and Taft systems. The Proving Grounds were located at this site until 1919, when they removed to Aberdeen, Md.
Following the 1876 Exhibition the No. 2 gun was shipped to Sandy Hook for additional testing. In 1903 the commandant of Fort Hancock requested of the Ordnance Department that this piece be transferred to the grounds of the fort so that it could be preserved as a monument “to the old class of guns.” This request was granted and No.2 is still sited at the north end of the post grounds.
The Peruvian Cannon
I am indebted to artillery historian Wayne Stark and his associate Sr. Gilles Galté of Valparaiso, Chile, for the information on this little-known gun.
In the decades preceding and following the American Civil War, the Pacific republics of South America were in a period of almost constant unrest. Peru and Chile were intense rivals over the ownership of the region’s extensive nitrate deposits. Nitrate is the chief ingredient of gunpowder and with the increased militarism of the western nations it became a very valuable commodity.
It was during this period of time that the Peruvian government either procured or had cast for itself a 20-inch Rodman. There are no U.S. Ordnance records for this piece. Two giant smoothbores were placed in the fortifications of the port of Callao, Peru — a 20-inch Rodman and a 20-inch Dah1gren.
Peru and Chile engaged in what was called the War of the Pacific, 1879-83. As a result of this conflict Peru was forced to cede the nitrate rich province of Tarapacá to Chile and lost valuable armaments when the port of Callao fell to Chilean forces in the spring of 1881.
The following excerpt is from the Valparaiso (Chile) Mercury.
Friday, 20 July, 1881
“Cannons for Caldera” [a Chilean port]. We received written word this date ... the national transport “Matias Cousino” will arrive here from Callao bringing in its hold four beautiful cannons for new fortifications that will be constructed here. The caliber of these pieces is: two monsters of one thousand pounds [projectile weight, the Rodman and the Dahlgren] and two smaller ones of 450 pounds [11-inch Blakely rifles?].
Sr. Galté has been unable to determine the final disposition of these weapons.
Capt. Art Krause of Spruce Head Island maintains the Ordnance Survey, State of Maine. When he finds a cannon with an interesting history he often shares this information with the readers of The Artilleryman.