Granite Forts

[Josh The Lighthouse Guy]

Masonry/brick fortifications were shown during the American Civil War to be obsolete. Modern rifled artillery had blasted holes through Fort Pulaski and reduced Fort Sumter to a pile of rubble.

While most Third System forts were made from brick, there were some forts - mostly in New England - made of granite. These forts seem to have been abandoned along with their brick contemporaries.

Could granite hold up to rifled artillery fire better than brick? Was this ever tested by the US Army?

 

[Sivart]

Granite would probably hold up better than brick against rifled artillery because it's harder and more durable. Rifled guns, introduced in the mid-1800s, were way stronger than older cannons, and they could blast through thick walls of brick like those at Fort Pulaski during the Civil War.

Some forts, especially in New England, were built with granite instead of brick, like Fort Warren in Massachusetts, because granite was stronger. But while granite was tougher than brick, it wasn't immune to rifled artillery. Even these granite forts could still be damaged by powerful shells, though they might take longer to crack compared to brick.

The U.S. Army never really did major tests on how granite held up against rifled artillery, but they saw in the Civil War that old forts, whether made of granite or brick, couldn't withstand modern artillery for long. After the war, military fortifications started to focus on newer designs that could handle the power of rifled guns, and both granite and brick forts were eventually replaced by more modern, flexible defenses.

 

[gary]

No to granite. Remember the rock shards at Pea Ridge? Confederates sheltered themselves among the rocks and were torn up by shards tht broke up under Union artillery. Soft soil or sand like at Battery Wagner

 

[tony_gunter]

No to granite. Remember the rock shards at Pea Ridge? Confederates sheltered themselves among the rocks and were torn up by shards tht broke up under Union artillery. Soft soil or sand like at Battery Wagner

The bedrock limestone at Point of Rocks held up pretty well at Grand Gulf during the naval bombardment. I wonder if it was the slope of the bedrock deflecting rather than absorbing the shots?

 

[13 IL Cav & 64 GA Inf]

No to granite. Remember the rock shards at Pea Ridge? Confederates sheltered themselves among the rocks and were torn up by shards tht broke up under Union artillery. Soft soil or sand like at Battery Wagner

Good thought, @Tony Gunter.

 

[rebelatsea]

Putting my railroad hat on, I have worked with granite ballast, hand loading /unloading and shovel packing. Gloves are essential as granite can shiver into very small shards and if it gets inro or under the skin festers readily. Imagine then the effect of a granite wall being struck or penetrated by heavy projectiles on the defenders.

 

[Reconstructed Rebel]

The bedrock limestone at Point of Rocks held up pretty well at Grand Gulf during the naval bombardment. I wonder if it was the slope of the bedrock deflecting rather than absorbing the shots?

The limestone shelf along the creek bed on our farm looked like it was composed of sand and fossils. If you rubbed the stone, sand particles came off rather easily. That said, I think the composition of limestone can vary a great deal …but it sounds like it could be able to absorb shots better than other types of stone.

 

[Josh The Lighthouse Guy]

The limestone shelf along the creek bed on our farm looked like it was composed of sand and fossils. If you rubbed the stone, sand particles came off rather easily. That said, I think the composition of limestone can vary a great deal …but it sounds like it could be able to absorb shots better than other types of stone.

Limestone is a soft rock. In its softest form (coquina) cannonballs may simply become embedded in the stone.

Granite is a much harder stone.

 

[Dan Kohli]

Putting my railroad hat on, I have worked with granite ballast, hand loading /unloading and shovel packing. Gloves are essential as granite can shiver into very small shards and if it gets inro or under the skin festers readily. Imagine then the effect of a granite wall being struck or penetrated by heavy projectiles on the defenders.

With how thick the walls were, I imagine that there wouldn't be much spalling on the inside of the fort until the is close to being breached.

 

[rebelatsea]

With how thick the walls were, I imagine that there wouldn't be much spalling on the inside of the fort until the is close to being breached.

That's probably true, the danger comes with cracks developing. Granite dust can also affect the lungs.

 

[gary]

rebelatsea - You're right. Fine powdered stuff is not good for the lungs. Never even thought of granite dust, but I'm not a miner and I don't smoke.

 

[Irishtom29]

Smooth bore cannon broke down stone and brick walls going as far back as the 1400s. Rifled cannon just did it quicker and from farther away. The big change came with high explosive shells that forced forts underground.

19th Century American seacoast forts often followed the school of Montalembert and had high masonry fronts facing the water that maximized the amount of cannon available and these fronts were not expected to have to stand up to heavy fire from enemy ships, the idea being the fort's guns would overwhelm those of the ships. The increased range of rifled cannon on occassion made such fronts vulnerable to land based cannon. The land fronts of such forts were usually provided with a glacis that protected the walls.

This view of the land front of Fort Barrancas at Pensacola shows the excellent protection provided by the glacis.

 

[gary]

Walls of Constantinople. Did you know the Ottomans casted their cannon in situ? They'd break it up into pieces and haul it via horse/camel to the next town and cast it afresh. No fancy trunnion or elevation screw.

 

[Irishtom29]

Walls of Constantinople. Did you know the Ottomans casted their cannon in situ? They'd break it up into pieces and haul it via horse/camel to the next town and cast it afresh. No fancy trunnion or elevation screw.

In the late 15th Century the French developed light bronze guns firing iron shot, this new artillery was both more powerful and more portable than the vastly heavier early cannon such as the Turks used against Constantinople and Rhodes and revolutionized warfare. The Italians were the first to feel the effect of the new cannon when Charles VIII invaded Italy. Thus the Italian development of new fortifications designed to both resist and mount cannon, though earlier transition fortifications were used by the Knights of St. John at Rhodes. But the Italians really got busy with it.

 

[Rhea Cole]

This is an interesting essay on granite use in fortification & construction.
•
Link:

The History of Granite: From Ancient Architecture to Modern Homes

Granite's durability and beauty have made it a favored material in architecture and design, from ancient civilizations to modern homes.

superiorgranite.com

 

[rebelatsea]

rebelatsea - You're right. Fine powdered stuff is not good for the lungs. Never even thought of granite dust, but I'm not a miner and I don't smoke.

I didn't even think about it until a Health and Safety guy watched us loading and unloading new ballast and told us we should be wearing masks or ensure the stuff was damped down, preferably both.

 

[Rhea Cole]

What you all are discussing is the danger of silicosis It is caused by exposure to fine particles of silica in the granite dust. Even a brief exposure can do irreparable harm to lungs.

Sharper than razors, the silica dust destroys lung tissue. The resulting swelling & scaring cannot be reversed. The minute particles cannot be removed.

Flint knappers have to be extremely careful because of the threat posed by Silica. You never knap flint inside a closed in space. They have to be very careful about contamination of their home via dust on their clothes.

What Is Silicosis?

Work around a lot of dust and wondering if your cough is a respiratory infection or something more? Here’s what you should know about silicosis.

my.clevelandclinic.org

Side bar:

I encourage you all to experience flint knapping. At Old Stone Fort TN State Archeological Park my G-granddaughter & I have taken lessons. ( Much to the girls amusement at me taking napping lessons…)

Here are her points. It is surprising easy to make a basic projectile point.

We also made atlatls with a hatchet & fletched darts.

Again, it was surprising how quickly she learned to launch the dart with her atlatl.

When you come to Middle Tennessee to tour Civil War sites with a family, check out the many daily & weekend programs at the parks. You are never more than 28 miles from a TN state or National Park.