Naval Arty Monitor's Dahlgren was Inspected by.....

CivilWarTalk

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For at least 158 years, two guns and the ship they were aboard, have captured the imaginations of Civil War historians, Naval Warfare experts, and Artillery lovers like myself. The two Dahlgren guns aboard the U.S.S. Monitor are among the most well known pieces of Naval Artillery, as well as subjected to the heaviest amount of study. When you consider their recovery in 2002, these guns are likely to be two of the most famous artillery pieces of the entire Civil War.

But, a few pieces of information about these big guns have eluded historians for all of that time, and have only recently been revealed. Hidden by a copper alloy trunnion cap, no-one has seen the markings on the trunnions of these guns since before they were mounted inside the armored rotating turret of the Monitor all those years ago!

You may recall that the U.S.S. Monitor, after sinking off the shores of North Carolina during the Civil War, these guns, and the Monitor's full turret were recovered from the salty ocean waters of the Atlantic in 2002. Since that time the recovered gun barrels have been placed into tanks filled with a solution that slowly removes the salt that's imbedded within the iron, each gun quietly waiting for the day it can be dried off, painted, and put on public display. Conservation work has been ongoing to complete this task, and every so often the guns are removed from the tanks to do further conservation work and other maintenance.

During a recent maintenance period when the No. 27 gun was having it's bore drilled clean of ocean sediment, the copper cap was removed on the left side of the gun and the photo below was taken, revealing for the first time in a very long time, the gun's Inspectors Marks!

12DFC7E9-D7C3-468F-B705-CD059A6EBD22.jpeg

Photo Courtesy of the Mariners' Museum and Park
Showing the Trunnion Markings on Monitor's Port Gun "WORDON"
A Dahlgren XI-inch shell gun, MNMS.2002.001.469A
As you can see the engraving shows a "P" for Proof, this is the Naval Proof Mark, showing this gun is tested and accepted for U.S. Naval Service.

The engraving also shows T. A. H. for Timothy Atwater Hunt, the U.S. Naval Ordnance Inspector from 1856 to 1859.

There is a good chance that both of Monitors Guns, which are sequentially numbered #27 and #28, were inspected by Hunt. However, Gun #28 won't have it's copper cap removed for at least a year at this point, but it would be really unusual if it didn't have Hunt's Inspectors Mark!

Additionally, to add to this wealth of knowledge, the next sequentially numbered West Point Foundry gun from 1859 was the XI-inch Dahlgren Shell Gun, Registry #29 from the U.S.S. Savannah. This gun also has Timothy Atwater Hunt's initials on it, as it was probably inspected together at the same time with the other two guns, making Gun #28's inspectors markings nearly a sure thing.

Also, from previous restoration work when the other copper caps were removed, we know that the guns are marked "XI in." and "1859" on the right trunnion, showing the casting date and the bore size of 11 inches.

Caliber and Year of Fabrication, Right Trunnion
XI in.
1859

Proof Mark and Initials of Inspecting Officer, Left Trunnion
P
T. A. H.


One other neat thing I can now report, we've been trying to narrow down the correct foundry numbers for the Monitor's Dahlgrens, this is another area that knowledge is missing.

In talking to Erik Farrell, the lead Conservator on these guns, the only numbers engraved on the Monitor's Dahlgrens, besides the ones I've described in my previous documents, is a number marked on each gun right behind the sight block at the breech end of the gun. Gun 27 has a number 107, and Gun 28 has a 110 engraved in the same spot. I do know that Rodman Guns from Fort Pitt put the foundry number in a similar area, although I believe it's on the sight block itself..

Photos of these numbers may be coming sometime in the near future!

Coming from the world of Army field artillery, I thought that the foundry number, especially a foundry number from the West Point Foundry, was going to be found at the rimbase. Erik assures me there are no numbers on the gun in this area on either side, unless they've been worn off.

I had a theory that maybe the number at the breech was the preponderance of the gun, or the differential of weight in pounds on the breech side of the trunnions, basically a number for any engineer attempting to move and mount the gun who would need this kind of information for proper support in transport, storage, and use.

In doing my research, it seems that Dahlgren's Shell Guns have a 9 to 11% preponderance, and that number should be more like 1,400 to 1,600 lbs.

107 lbs. of preponderance would be less than 1%, so that just doesn't add up.

What's more likely, is that Registry Number 27 was the 107th XI-inch Dahlgren Shell Gun casting by the West Point Foundry. Registry Number 28 was the 110th casting.

In reading Dahlgren's memoirs, he claimed to "over proof" many, many, guns by filling them with double and triple powder charges, and shooting them in an attempt to tease out weaknesses. It makes sense that many barrels would have failed, or been used up in these proofing tests, and were likely recycled as scrap metal.
  • US Casting Foundry: West Point Foundry, Cold Springs, New York
  • Year of Manufacture: 1859
  • Tube Composition: Cast Iron
  • Registry Number: 27
  • Foundry Number: 107 (tentative)
  • Inspecting Ordnance Officer: T. A. H. - Timothy Atwater Hunt, U.S. Naval Ordnance Inspector, 1856-1859, & 1862-1867
  • Additional Engraving: added during a maintenance period in October of 1862...
    • Gun 27: "WORDEN. MONITOR & MERRIMAC."
  • Purchase Price in 1859: $1,391.00 (US)
Usually all of us artillery guys would run to our tomes of data by Ripley, Olmstead, Hazlett, & Stark for data like this, but even those guys didn't have all the information on the Inspector's Marks, or Foundry Numbers from the U.S.S. Monitor's Dahlgrens, all those sources had blanks for these bits of data!

More information about these guns is expected over the coming months, but CivilWarTalk needs to thank Archaeological Conservator Erik Farrell for his help with our research, as well as providing the above photo!

Do you know more about early Dahlgren Foundry Numbers or Markings?

Later documentation shows that the rimbase was a standard location for foundry numbers, as well as on end of the upper breaching jaw, and also the head of the pin? I'm not sure where the pin is? It also mentions the foundry number can be found on the cascabel block, I'm assuming that's the block the rear sight mounts to, but I'm not completely sure.

It also says the top of the upper jaw should have the preponderance in pounds in light stamping. From what Erik says, this isn't visible on the gun. Maybe it's worn away.

Could sure use a Naval Artillery Expert for these questions!

For the full history I've written on both guns, please see this page:
https://civilwartalk.com/threads/monitors-xi-inch-dahlgren-shell-guns.166641/
 
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CivilWarTalk

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Would inspection involve firing the guns, or was he just looking for cracks and obvious imperfections?
I believe it included firing the gun several times with a set charge and ball, checking for flaws in casting, and performance, and making sure all the weights and measures of the gun are in tolerences. They may have also done things to check the brittleness of the gun metal.

I’m not 100% sure, but proof testing might have also required sacrificing one or more guns in a batch to destructive test firing, over loading the gun to see how long it survives, what type of stress it can handle.
 

ucvrelics

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I believe it included firing the gun several times with a set charge and ball, checking for flaws in casting, and performance, and making sure all the weights and measures of the gun are in tolerences. They may have also done things to check the brittleness of the gun metal.

I’m not 100% sure, but proof testing might have also required sacrificing one or more guns in a batch to destructive test firing, over loading the gun to see how long it survives, what type of stress it can handle.
There is a lot of great info in his book about all the testing etc. One of my favorite stories in the book is when he went on board a Russian ship and they had 2 of his guns. He had a conversation with Cyrus Alger
 

CivilWarTalk

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There is a lot of great info in his book about all the testing etc. One of my favorite stories in the book is when he went on board a Russian ship and they had 2 of his guns. He had a conversation with Cyrus Alger
I read the whole memoir from his time starting in the Ordnance Department, right through the Battle of Hampton Roads back last December to learn as much as I could about the development of the XI inch Shell Gun, I'll need to pick it up where I left off soon!
 
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