Result of Early 1862 Ironclad Test

DaveBrt

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From the Engineer Bureau Outgoing Letters Ledger, National Archives

March 20, 1862

Lieut. Henry T. Douglas, PACS
In charge or Defences, Yorktown

*****
I think the water battery should be abandoned at Yorktown, for the reasons specified in a former letter, & because of the invulnerability of iron clad vessels of proper build. When you expressed your confidence in the ability of a 64 pdr. to contend with an iron clad vessel, you were not aware that 180 pdr. solid shot had been used at 20 yards range for 4 hours without appreciable effect, at least such is the information I received here.
*****
Alfred L. Rives
Acting Chief Engr. Bu.
 
Interesting letter was apparently written not long after the battle of Hampton Roads on March 9, 1862 between the ironclads Monitor and Virginia (aka Merrimac). Was Alfred Rives providing information gained about the ordnance used in that battle to explain his judgement about abandoning the Yorktown battery?
 
Interesting letter was apparently written not long after the battle of Hampton Roads on March 9, 1862 between the ironclads Monitor and Virginia (aka Merrimac). Was Alfred Rives providing information gained about the ordnance used in that battle to explain his judgement about abandoning the Yorktown battery?
No, the Confederates did a test to determine the thickness of the plates to put on Virginia. I think that is what he was talking about.
 
There's something odd about that report as the US 64pdr SB was only just short of the British 68pdr 95cwt in muzzle velocity and should have been capable of defeating the laminated armour as then used. Also you can't fire 180lb shot from a 64pdr ! Someone. can't remember who has pointed out the 64pdr on here before.
 
I actually think it might have been talking about Monitor/Virginia because of the "four hours" note. The 180 lbs is not far off the expected weight of wrought iron balls for an 11" gun (166 lbs cast iron ball, wrought iron is 7.6% more dense than cast, so the mass of a wrought iron ball is 181 lbs)* and there were some wrought iron balls aboard Monitor but they just weren't considered safe to fire.

Have some misconceptions and misunderstandings mixed in and I can see how the Monitor-Virginia battle could have been regarded as "180 pounder solid shot used for four hours".


Of course, the thing that's been missed here is the critical importance of muzzle velocity - Rives here is writing as though projectile mass is the be-all and end-all.



* this means that you'd need an 11" or 12" smoothbore to fire a 180 pound projectile - that or a rifle somewhere in excess of 8".
 
Whichever event he was referring to, I posted this, not as fact, but to show the mind of the lead engineer in the Engineer Bureau in Richmond. He initiated some, and reviewed many other, defensive plans for defensive works. This is the lens through which he was planning.
 
It's certainly interesting, and if his view was shared by others in America (and we do know it was) then it explains why the Dahlgren system of large slow heavy projectiles for battering was favoured.

If I recall rightly it's about this time that experiments in Britain demonstrate that for contemporary armour a given system has a constant work required to penetrate in terms of foot-tons of energy per inch of circumference of the ball.
 
breech loading cann HMS Warrior.jpeg

110 pdr Armstrong breechloading gun HMS Warrior.


In England, they went entirely overboard in testing ironclad armor. They fired a 300 pound Armstrong breech loading rifle at 5.5" armor plate backed up by .9" of teak at 200 yard range. The first shot did not penetrate the teak backing. The second & third shots did. The fourth shot "malfunctioned," a euphemism for blowing the breech 40 yards to the rear. Sir William Armstrong's breechloading design had been for 12-20 pdr field guns. Sir William had stated that he would not guarantee its use on larger, let alone gargantuan, cannon.
 
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In England, they went entirely overboard in testing ironclad armor. They fired a 300 pound Armstrong breech loading rifle at 5.5" armor plate backed up by .9" of teak at 200 yard range. The first shot did not penetrate the teak backing. The second & third shots did. The fourth shot "malfunctioned," a euphemism for blowing the breach 40 yards to the rear.
Can you provide a citation as to the effect that that was an Armstrong breech loader? I believe the test you're talking about was a muzzle loading smoothbore firing 150 pound shot that would have been 300 pounds if rifled, if it's the one I'm thinking of.

https://api.parliament.uk/historic-hansard/commons/1862/apr/10/the-warrior-target-at-shoe-buryness


With regard to the question of his hon. Friend (Mr. H B. Sheridan) he thought he had better refer all who took an interest in the important experiment which took place last Tuesday, to an article which had appeared in The Times. Nothing could be fairer, or, he might add, more graphic, than the description which The Times gave of that experiment. He would only state shortly that there were four shots fired from what was called the 300-pounder Armstrong— that is, as a smooth-bored gun, it fired a shot of 150 lb.; but, if rifled, it would fire an elongated shot of 300 lb. On Tuesday last the first experiment was with a shot of 150 lb., and 40 lb. of powder. It was fired at the Warrior target, at the distance of 200 yards; but he was bound to say that the target had had 766a good deal of shaking by previous experiment. The first shot struck the target on a part which had been, he thought, rather more shaken than the other parts of it. The shot entered, made a hole in the armour plating, and passed through eighteen inches of backing, being stopped by the inner skin of the ship, but it crucked that skin. The next shot, with 40lb. of powder, hit nearly on the same spot. The fragments of the shot went through plating, backing, skin, and all; and there were proofs that it would have created considerable damage in the interior of a vessel. The third shot Sir William Armstrong requested might be fired with 10lb. of powder additional; but some doubts were entertained, not whether the gun would stand such a charge, but whether so large a charge would be burnt to give the shot greater velocity. The third shot was fired with 50lb. of powder, and fired at that particular part of the target which represented the strongest part of the ship. The fragments of the shot went through the plating and backing, and he believed were buried in the supports at the back of the target. It was not very easy to say whether the whole charge of powder had burnt, but evidently a good deal more powder had burnt, because the effect was much greater. The fourth shot took place under the same circumstances. It went through the plating and backing, and buried itself, like the previous shot, in the scaffolding at the back. In reply to the last question of his hon. Friend, whether the 300-pounder gun could be worked on board ship, it was hazardous for him to say decisively, but he believed they could carry a 300-pounder on board ship; but at the same time it was questionable whether a ship could carry plates sufficiently thick to resist it.


It also burst not on the fourth shot, but on the 162nd:

https://api.parliament.uk/historic-hansard/commons/1862/jul/10/question

136
§MR. BERNAL OSBORNE
said, he rose to ask the Secretary of State for War, Whether the 12-ton gun of Sir William Armstrong's construction has burst during the recent experiments at Shoeburyness; also, how many Guns of the same description and weight have been ordered, and if any of a still larger size are to be constructed on Sir William Armstrong's principle?
SIR GEORGE LEWIS
said, he had to state, in answer to the question of the hon. Gentleman, that on the occasion of the recent experiment at Shoeburyness the breech of the 12-ton gun was blown off, the cause of it being the unusual severity of the proof to which it was subjected, the charge of powder extending to 60, 70, 80, and 90 lbs. of powder. Not less than 162 rounds had been fired; and as the gun was merely an experimental one, it must be considered that it was exposed to a stronger trial than such guns were usually subjected to. The number of the guns of this size ordered was fourteen, and there were also a 600-pounder rifled gun and a 300-pounder smooth-bore in course of construction.


This was the prototype of the 9" 12-ton gun
 
From the Duke of Cambridge, 11th April:

I believe, that if ever it was proved to the satisfaction of military and naval men that a combination of defences was essential in such a position as that of Spithead, such has been fully and fairly demonstrated by the last experiments at Shoeburyness, and I venture to think even by what happened the other day in America. Because what my noble Friend said is fully borne out by the newspaper report, namely, that when the Merrimac was to a certain extent injured by the Monitor she retired under the cover of the forts, and the Monitor did not pursue her or venture to expose herself at close quarters to the guns of those fortifications. After the experiments at Shoeburyness people have been much surprised 849that in America the ships were so little injured: but I should be inclined to suppose that this arose from the American guns being all shell guns, and throwing nothing but hollow shot; while the shot with which such great effects were produced at Shoeburynesson Tuesday were solid shot. Nor ought we to overlook the charges of powder that were used in the two cases. When we used charges of 40 lb. of powder, the target resisted the shot; but when we used a charge of 50 lb. of powder with a shot of 150 lb., the effect was, as we know, very remarkable. The Americans, on the other hand, used only 12lb. or 14lb. of powder to a shot of 180 lb. The result was, that the American guns were comparatively useless. It is clear, therefore, that the amount of powder for the charge is a very important element in the question.


Note that the British here think the shot fired at Hampton Roads was 180 lb - not the true value of 169. This seems to me to indicate that the "Hampton Roads firing = 180 lb" misconception is plausible.
 
The 300 pdr Armstrong test referred to in my post was reported in The Scientific American. Another, more detailed description of the 300 pdr is in From Breechloaders to Monster Guns: Sir William Armstrong & the Invention of Modern Artillery, 1854-1880.


In front of the U.S. Navy Museum is Willard Park. Among the artifacts on display are two Civil War armor test plates.

test plate 2.jpeg



NMUSN_Willard_Park_Civil_War_Test_Armor_Plate_2.jpg

NMUSN images
 
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The 300 pdr Armstrong test referred to in my post was reported in The Scientific American.
My suspicion is that what's going on here is that a real misconception in Britain (it was thought at the time that the 12 ton gun had burst during the first tests, but if I recall rightly it had merely dismounted; they actually asked if the bursting had taken place in Parliament) was reported as fact in Scientific American, much like how the real misconception in parts of America (the "180 pound" 11 inch Dahlgren shot) was reported as fact in Parliament.

To my knowledge there was never a 300 pounder Armstrong breech loader, for the very good reason that the 7" 110 pounder was considered to have too low a safe powder load for AP work, and the fact we can identify an Armstrong muzzle loader referred to at the time as a "300 pounder" strongly suggests that this is the Armstrong 300 pounder being referred to.
 
My suspicion is that what's going on here is that a real misconception in Britain (it was thought at the time that the 12 ton gun had burst during the first tests, but if I recall rightly it had merely dismounted; they actually asked if the bursting had taken place in Parliament) was reported as fact in Scientific American, much like how the real misconception in parts of America (the "180 pound" 11 inch Dahlgren shot) was reported as fact in Parliament.

To my knowledge there was never a 300 pounder Armstrong breech loader, for the very good reason that the 7" 110 pounder was considered to have too low a safe powder load for AP work, and the fact we can identify an Armstrong muzzle loader referred to at the time as a "300 pounder" strongly suggests that this is the Armstrong 300 pounder being referred to.
What can I say, that's what's in the article & when I checked there were numerous online references as well. The book I cited also covers the 300 pdr. Everything I know on this topic comes from them.
 
What can I say, that's what's in the article & when I checked there were numerous online references as well. The book I cited also covers the 300 pdr. Everything I know on this topic comes from them.
Misconceptions can enter the public consciousness by mistaken people repeating other mistaken people; that being said, if the From Breechloaders to Monster Guns article (not a book, it's about 35 pages) specifically states the 300 pounder as being a breechloader I will be very surprised.
I'd also be interested in the date at which the gun is claimed to have burst, because if it's in late June to July and it doesn't mention that the gun had fired about 160 shots by then it's a distinctly incomplete picture.
 
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