Wooden Rodman mounts

[rifleshooter2]

I was doing a little research on a future project and found this interisting photo of Rodmans on wooden mounts I assume they are confederate. All of the other mounts I have ever seen them on were metal.



Andy

[Zulu]

rifleshooter2,
I want to build one of these mounts in the barbette fashion for one of my full scale concrete barrels.  I'm not sure where I would put it yet.  I find them very interesting.
Zulu

[Cannoneer]

I was doing a little research on a future project and found this interisting photo of Rodmans on wooden mounts I assume they are confederate. All of the other mounts I have ever seen them on were metal.



Andy

Andy,
Those are CSA Columbiads which were cast at either the Tredegar or Bellona Foundries in Virginia. The profiles of these guns resemble Rodmans, but they are not manufactured the same way; these large (8 & 10-inch) bore Southern cannons had a bad habit of blowing up. The CSA didn't possess the manufacturing ability to produce the iron Barbette carriages that the U.S. was mounting Rodman guns on, which is the reason for the longer trunnions seen on the Confederate cannons.

[Zulu]

Boom J,
These carriages had to have trunnion caps didn't they?  It is hard to tell if there are any in this picture.
Zulu

[Soot]

There are quite a few big guns that didn't use trunnion caps. The angle of the carriage, 3-7 degrees or so, held it all together somehow.
I still think it was quite a leap of faith to think this might work, but solid engineering prevailed.
[img width= height=]http://www.seacoastartillery.com/gallery/images/129_2929.jpg[/img]

[Terry C.]

Many of the big guns did not have trunnion caps.

One feature of these Confederate guns that distinguish them from Union Rodman guns is that the trunnions are much longer.

It could be assumed that they were designed from the outset to be used on wooden mounts, as the short trunnions of Union Rodmans are not well suited to this type of mount.

[rifleshooter2]

I was doing a little research on a future project and found this interisting photo of Rodmans on wooden mounts I assume they are confederate. All of the other mounts I have ever seen them on were metal.



Andy

Andy,
Those are CSA Columbiads which were cast at either the Tredegar or Bellona Foundries in Virginia. The profiles of these guns resemble Rodmans, but they are not manufactured the same way; these large (8 & 10-inch) bore Southern cannons had a bad habit of blowing up. The CSA didn't possess the manufacturing ability to produce the iron Barbette carriages that the U.S. was mounting Rodman guns on, which is the reason for the longer trunnions seen on the Confederate cannons.

Thanks Good to learn something I never even noticed the trunnions.

Andy

[Cannoneer]

There are quite a few big guns that didn't use trunnion caps. The angle of the carriage, 3-7 degrees or so, held it all together somehow.
I still think it was quite a leap of faith to think this might work, but solid engineering prevailed.
[img width= height=]http://www.seacoastartillery.com/gallery/images/129_2929.jpg[/img]

The angle of the carriage certainly affects the design of the trunnion pockets, but I think the most important design feature is that the trunnion pockets be higher in the back. It is kind of amazing that only the weight of the barrel, and the configuration of the trunnion pockets made it possible for these large guns to be fired without the recoil making the barrel jump off the carriage. It must have been a brave/brilliant engineer that first held the concept that these carriages didn't need capsquares to hold the barrels securely.

[gulfcoastblackpowder]

I don't know that it's really that much of a stretch to consider designing without trunnion caps.  The design of any carriage - with or without caps, should be such that the cannon's recoil is fully supported by the carriage, and the caps are there as an extra measure of safety, but are not providing any functional use during a normal firing.  I know on my naval carriage, I could fire the gun at almost any angle above 0 without fear of it jumping, even if I removed the caps.  I never would...but it should work fine. 

Angling the cannon down would be another matter entirely.  For that, I'd want to at least angle the whole carriage on a track system, kind of like these Columbiads.

[Soot]

I think the most important design feature is that the trunnion pockets be higher in the back.

The angle of the carriage is what makes the pocket higher in the rear, the pocket itself is 180 degrees.

[seacoastartillery]

   Boom J. was correct when he wrote:

There are quite a few big guns that didn't use trunnion caps. The angle of the carriage, 3-7 degrees or so, held it all together somehow.
I still think it was quite a leap of faith to think this might work, but solid engineering prevailed.
[img width= height=]http://www.seacoastartillery.com/gallery/images/129_2929.jpg[/img]

The angle of the carriage certainly affects the design of the trunnion pockets, but I think the most important design feature is that the trunnion pockets be higher in the back. It is kind of amazing that only the weight of the barrel, and the configuration of the trunnion pockets made it possible for these large guns to be fired without the recoil making the barrel jump off the carriage. It must have been a brave/brilliant engineer that first held the concept that these carriages didn't need capsquares to hold the barrels securely.

     The trunnion pocket or cradle IS higher in the back AND we know that the 3 deg. pitch of the Chassis rails makes the back edge of the pocket Even Higher.  We know this to be true from studying the drawings that exist AND visiting actual carriages at forts around the country.  The first carriage we studied revealed very interesting details in the area of what we call the trunnion cradle.  The 1859 iron, seacoast, front pintle, barbette upper carriage we measured at Fort Pulaski near Savannah, Georgia was 40.333 in the front and 41.100" high in the back.  For those measurements, we used the top surface of the Chassis rails as a Datum.  Our empirical results match the math on the 1868 100 Pdr. Parrott Carriage drawing pretty well.  Specified angles are not found on the 1862 drawing we have and the 1859 drawing does not exist as far as we know, if it ever did.  

      Our interpretation of the 1868 drawing indicates exactly what we learned in 2004 at Watervliet Arsenal, where we searched for and finally found an original 1862 iron carriage drawing.  The ordnance curator we talked to explained that, although you don't find the degree numbers on the 1862 drawing, 3 degrees for the Chassis pitch and 3 degrees for the top of the Upper Carriage, the rare working drawings used in the various shops contained the information in border notes which are called General Notes, and drawn into one particular section, today.  So according to him an original carriage assy. should display a total of 6 degrees forward pitch to contain the tube physically during recoil.

       The math is simple and agrees with that carriage we studied in Georgia and the 6 degrees forward pitch specified on the 1868 drawing.  

                             The top edge of the 1859, 1862 and 1868 iron, upper carriage for the 100 Pdr. Parrott is 14" long.

                                                       The deviation for 1 deg. is .0175" per inch.
                                                       The deviation for 3 deg. is .0525" per inch.
                                                       The deviation for 3 deg. is .735"  per 14 inches.
                                                       The deviation for 6 deg. is 1.470" per 14 inches.
    
     Since the trunnion dia. is 6.4", you are back to about half of that 1.470" height difference or .672", because 6.4 is 45.7% of 14.0".  So, you have more than 5/8" extra metal behind the trunnion to physically block it from lifting up and out of the trunnion cradle during recoil.

     Even our 1/6 scale re-creations of this gun and carriage do not have a problem with tube ejection upon firing.  AND, the recoil can only be described as vicious on our guns, even with everything built to scale and fired with scale size and weight bolts and powder charges.  You should have seen the dorky duo shoot the first shot!  We must have used half a roll of duct tape on the tube and carriage!!

FYI,

Mike and Tracy

Fort Pulaski Parrott rifle and 1859 carriage.




Also within Confederate, Battery Magruder, at Yorktown on the Peninsula, these 8" Columbiads, are located on similar wooden, seacoast, center-pintle, barbette carriages.

[RocklockI]

Add in the 3 degrees or so of the uphill reciol system built into the carriage .

to slow ,,,never mind Tracy mentioned the 3 degrees thing  

[Soot]

I don't believe I lifted the image since I made the image a clickable link to your site, but that might not be obvious so I will amend the situation and edit the post.

[KABAR2]

Something to also note in the original photo is each gun seems to be named

has anyone ever done any research on the naming of the big guns?

[seacoastartillery]

     First, I owe an apology to Soot, because my rudimentary computer skills made his fairly obvious link to our Seacoast Artillery site invisible to me.  I am truly sorry, Soot, you're a good guy and a great cannon maker and I didn't mean to offend you.  I had my children look over my post and they berated me severely, saying DAD!, you can't say THAT!  Plus delete this, delete that!  Why did you write that??  Bad Dad, Bad Dad!  So they deleted all that shouldn't be there.  Hope you will like the posting better now. I do, and the most important stuff is still there, but no remarks that could be considered disparaging.  I understand now that when the cursor arrow turns into a hand that it means the photo is linked.  You see I was just ignorant and that has been corrected.


     KABAR2,     The breech of the big gun in Battery Chatfield adjacent to Fort Putnam at Cumming's Point on Morris Island opposite Fort Sumter in Charleston Harbor is marked Col. Chatfield in honor of the 6th Connecticut Infantry who participated in the assault on Battery Wagner in July of 1863.  This photo appears in the Pictoral History of the Civil War, ten volume series published in 1911.  Like most of the photos in the volume on forts and artillery it is too small and fuzzy to be scanned and shown here.  There was one named 10" Columbiad in the 'Mound Battery' in Fort Fisher, North Carolina, but the name eludes me.  Most famous, of course is the Confederate Beauregard Gun which is an 8" or 10" Columbiad named in honor of General Pierre Gustave Toutant Beauregard, a famous Confederate Army leader.  On the other side you also have the Lincoln Gun, the first 15" Rodman produced and mounted at Fort Monroe in Hampton, Virginia.  It's still there today.

Older, but still willing to learn,

Tracy

[Cannoneer]

Something to also note in the original photo is each gun seems to be named

has anyone ever done any research on the naming of the big guns?

Allen,

I've never done any specific research on this topic, but I don't think there's any question that troops, cannon crews, the public, and the press gave names to certain cannons, especially the big guns.
In this case though, those aren't nick names of the guns painted on the carriages and chassis, I think that is the name of CSA General John B. Magruder, and Yorktown that is marked on both the gun carriages, and carriage chassis. This is just a guess on my part, but I think this photo may have been taken after the capture of Yorktown by Federal forces, because I've seen other Civil War photographs where captured CSA ordnance was similarly painted before being photographed.