Military Review

Rodman Cast Iron Bottles


For a long time there were no notes about weapons steampunk technology. So, we will catch up. So, in the middle of the XIX century, the American artilleryman Thomas Jackson Rodman developed a new casting technique for cast-iron artillery barrels, which made it possible to make durable and extremely reliable guns of very large calibers - up to 20 inches.

Rodman empirically established that if the casting is not cooled from the outside, but from the inside, then it turns out to be much stronger than usual due to the more uniform crystal structure of the metal and the absence of internal stresses. He designed a special injection mold with a cooled water core and external heating, preventing rapid cooling of the outer layers of the product. On tests, Rodman's large-caliber guns withstood over one and a half thousand shots, while barrels of the same caliber and with the same wall thickness, but cast using conventional technology, exploded after several dozen volleys.

Such high reliability attracted the attention of the American military to the invention of Rodman. Since 1861, in the USA, the production of Rhodmann guns of the 8, 10, 15 and 20 inches caliber has been adjusted. Most of them were cast ten inches - 1300 pieces, 15-inches made 323, and eight inches - 213. The heaviest - twenty-inch guns weighing 80 tons, firing 400-kilogram cores, made only a few copies, since this caliber was redundant.

Rodman’s guns, which were a mortal threat to wooden warships and really dangerous even for battleships, armed many American coastal forts, and they were also used as siege weapons. True, during the civil war they did not have time to shoot at ships, since the Confederation fleet preferred to stay away from enemy fortifications. Only two siege ten-inches Rodman were allegedly used in the so-called "Second Battle of Fort Sumter", although historians have no consensus on this. Some believe that heavy Dahlgren guns fired at the fort, outwardly similar to the Rodmans with their bottle form.

After the end of the civil war, Rodman’s coastal guns were in service for a long time and were finally written off only in 1905. Many of them have survived to this day. Special mention deserves the alteration in the 1870-s of a few dozen "rodmanovok" by pressing into their trunks rifled steel liners. Thus, ten-inch smooth-bore guns were turned into eight-inch rifles, which had a much longer range. These guns also served in fortresses until the beginning of the twentieth century, and according to some information they were put on monitors.

Rodman's gun barrel in the cut.

Drawing tools Rodman on the serf iron carriage with a turntable.

On the left is a drawing of a Rodman casting mold with a cooled core. In the manufacture of tools through the core pumped up to 200 tons of water, and the cooling time of the casting reached 65 hours. On the right - factory workers on testing of the next product.

Fifteen-inch Rodman (in the two upper pictures of the same gun) as part of the coastal defense of Washington during the civil war.

Rodman's 15-inch siege gun on a wooden folding gun carriage. In these guns, two types of vertical guidance mechanisms were used - with a worm screw, as in the figure, and more common with a lever and a “comb”.

A wagon for transporting Rodman’s siege weapon.

Fort McHenry's well-preserved coastal battery with two eight-inch and one 15-inch Rodman cannons.

"Rodmanovka" in the fortress of Fort Knox.

... and on the Santa Monica seafront.

Another fifteen inches at a coastal installation in Massachusetts.

The Perm Tsar Cannon, which is essentially a copy of the Rodman 20-inch gun, cast in 1868 using a simplified Rodman technology (without external heating of the mold). The successful development of this technique was the undoubted achievement of Russian gunsmiths.

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  1. Revolver
    Revolver 2 August 2015 05: 23
  2. dvg79
    dvg79 2 August 2015 05: 25
    An interesting article. We are waiting for new materials from the author.
  3. corporal
    corporal 2 August 2015 06: 38
    A monumental thing. And how much does this miracle weigh?
    1. Bayonet
      Bayonet 2 August 2015 10: 21
      Quote: Corporal
      And how much does this miracle weigh?

      The 20-inch Rodman cannon mounted right at the park entrance from 4th Avenue. It is impossible to miss - after all, a cannon weighs 53 tons and was thrown by cores weighing about 490 kilograms!
  4. parusnik
    parusnik 2 August 2015 08: 50
    Long time ago there were no notes about the weapon technology of steampunk..Yes ... quite a long time ... thanks ... It was from a cannon cast using Rodman’s technology that the heroes of J. Verne flew to the moon
    1. mirag2
      mirag2 2 August 2015 10: 38
      I just wanted to insert about Jules Verne’s cannon, about its casting, with Rodman’s technology there is nothing in common, no cooled core. Only incredible frenzied cheers and patriotism of the Artillery Club members))).
  5. moskowit
    moskowit 2 August 2015 09: 56
    Very interesting! Thank! The technology is understandable. And how was the loading process and the shot, what devices were used. After all, the weight of the charge and the projectile is not small. Shows the gun in the casemate, how did it charge?
  6. Aleksandr72
    Aleksandr72 2 August 2015 10: 14
    I already read this article here: The source is the same:
    Briefly about Rodman’s guns:
    15-inch "Columbiade", developed in 1861, barrel weight - 19 tons, ammunition - a nucleus weighing 181 kg or a bomb weighing 145 kg, powder charge weight 27,2 kg, the gun sent a 180-kilogram projectile as much as 4 meters ...
    The serial production of the gun was carried out for 10 years (from 1861 to 1871) at two enterprises - "Fort Pitt" and "Scott Foundry Cyrus Alger & Co." A total of 363 guns were produced, of which 25 have survived to our time.
    20-inch coastal gun, developed in 1863, barrel weight 59 tons, barrel length - 12 calibers (the sea gun was shortened and lightened — barrel length 10 calibers and 9 tons lighter), cast iron core weight 422 kg, powder charge weight 44 kg
    Another photo of Rodman's 15-inch Columbiade (next to a person for comparison):
  7. Andrey NM
    Andrey NM 2 August 2015 10: 32
    Something was needed about the loading process of this miracle.
    1. ICT
      ICT 2 August 2015 12: 09
      Quote: Andrey NM
      about the process of loading this miracle

      it seems something like this
  8. Grigorievich
    Grigorievich 2 August 2015 15: 06
    Quote: Andrew NM
    Something was needed about the loading process of this miracle.

    And what is the rate of fire?
    Such nucleoli to roll in the trunk belay
  9. Denimax
    Denimax 2 August 2015 15: 53
    It is easy to pick up and dispatch a cartouche, wad too. The core, probably the barrel will have to be lowered and the core rolled over the muzzle, put a wedge and raise the barrel. And there it will roll itself. winked
    In general, this is one of the most interesting sections in artillery.
    1. Andrey NM
      Andrey NM 2 August 2015 15: 56
      And on ships, how?
      1. Denimax
        Denimax 2 August 2015 16: 03
        Vaughn TIT laid out the scheme. In the Italian battleship Duilio, too, shoved through the barrel, only with a steam pusher. The 450 mm caliber was also not small.
  10. bootlegger
    bootlegger 2 August 2015 20: 16
    Last solid guns. Further gun trunks were made by hot landing the outer part of the barrel on the inside. The internal stresses created as a result of this made it possible to significantly reduce the thickness of the gun walls and its weight ...