600-pounders

Dumb questions: How in the world did they load those things and how much powder was used?
The only references that I have seen refer to the use of between 30 and 55 pounds of powder and they were loaded through the use of a hoist assembly.
 
Dumb questions: How in the world did they load those things and how much powder was used?

Charleston Confederate soldier-artist Conrad Wise Chapman did a watercolor or drawing showing one being loaded at a battery there; it was done using a block-and-tackle arrangement to hoist the charge and projectile to the cannon's mouth.
 
They were loaded at the muzzle using a hand crane or hoist, the charge varied from 30 to 55lbs, firing a 700lb shot or shell. The air chamber behind the charge was 7" diameter by 31" long, increasing the efficiency of the charge by 20 to 25%.
A hit from a 12.75" Blakely would go straight through any armour then existing at the then accepted battle range of 800 yards,
I hit would possibly sink a monitor eventually if the angle of a hull hit was such that it went through the waterline or below either going in or coming out. The wracking damage from impact would be severe anyway,
A turret hit would certainly put the turret out of action, even a glancing blow would probably be enough to concuss the crew, and anyone touching the interior wall would probably die.
No Union ironclads were ever hit by one of these monster weapons, but a good indication of what a shot could have done is the effect a 10" solid shot striking a monitors turret full on. Whilst it didn't penetrate all the way, it stopped the turret from turning and put it out of action.
 
From an article in the South Carolina Historical Magazine from April, 1996 by C.R. Horres Jr., the following information was obtained:
Originally 15" Columbiads (50,000 pounds ) were desired, but these proved to be impossible to be cast by Southern foundries. Captain Alexander Theophilis Blakely persuaded Major Caleb Huse to allow him to cast two experimental 12.75 inch rifled guns with carriages and 100 rounds of ammunition for the cost of $600,000 Confederate dollars. When finished the guns weighed nearly 50,000 pounds each and the carriages with all accessories weighed 58,000 pounds. The finished guns were 16 feet long from muzzle to breech and they were cast by the George Forester and Company's Vauxhall Foundry. Due to the massive size and weight of these guns, they proved difficult to transport. They were finally transported on the former Confederate raider Sumter along with 150 solid shot 20" long weighing 650 pounds each and 50 shells 22" long weighing 470 pounds each. The guns had to be shipped standing up which left the Sumter appearing to have three funnels. The existance of these guns was already known to the Union and orders were given for them to be captured before arrival. These efforts failed and they arrived in Wilmington on August 18, 1863. Due to the size and weight of the guns, special railroad cars had to be constructed to get the guns to Charleston and the first gun arrived on August 25th. The guns were to be emplaced on the Battery in Charleston and a temporary railroad track had to be laid to get them there. However, once the first gun had been transported to the Battery, it was decided to emplace the second gun at Frazier's Wharf. During one of the early test firings, due to improper loading, the cast iron breech of the gun on the Battery cracked in 11 places which required a cast iron plate to be bolted around the cracked breech. Union forces were aware of the guns' locations and close observations were made when they were test fired (they were never fired in anger). The only records of the gun's performance was from an October test firing which reported that a 470 pound shell could reach 6600 feet at 2 degrees elevation, so whether or not they had a 5 to 7 mile range was never proven. Also, they were shown to be not very accurate as the bolts tended to tumble end over end and coupled with the failure of the first gun during testing; these factors cast great doubt on the value of these weapons, except for a psychological value. The guns were destroyed on February 17, 1865 and the only portions of the guns existing today is the damaged breech in the Washington Navy Yard and a 500 pound fragment that was blown into an neighboring attic where it remains today. Thirty of the bolts were used to outline a Revolutionary War fortification on Marion Square, but they were sold for scrap in 1883-they brought $50.00.
 
The gunners ignored the instructions about the air chambers initially, and both the rifling and the bolts were improperly cast causing them to "rattle" in the bore and "puff" in flight. Something that was also found inherent in the initial Armstrong MLR rifling. They would have to gave been re-rifled or sleeved to have cured it. Woolwich Arsenal cured the problem by having two sets of rifling, one which took the shot down the barrel. upon firing the projectile studs were forced into the increasing twist "shunt" rifling. At Alexandria the power and accuracy of the 9" , 11", 12" and 16" surprised even the gunners.
Brooke's Rifles used a 7 groove uniform twist rifling and projectiles flew straight and true.
 
The gunners ignored the instructions about the air chambers initially, and both the rifling and the bolts were improperly cast causing them to "rattle" in the bore and "puff" in flight. Something that was also found inherent in the initial Armstrong MLR rifling. They would have to gave been re-rifled or sleeved to have cured it. Woolwich Arsenal cured the problem by having two sets of rifling, one which took the shot down the barrel. upon firing the projectile studs were forced into the increasing twist "shunt" rifling. At Alexandria the power and accuracy of the 9" , 11", 12" and 16" surprised even the gunners.
Brooke's Rifles used a 7 groove uniform twist rifling and projectiles flew straight and true.

According to the article, the instruction manual didn't arrive until some time after the guns had and the bronze air chamber weighed over 1400 pounds.
 
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