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“Bite-Size Bits of Local, National, and Global History”
“Bite-Size Bits of Local, National, and Global History”
Near Fort Washington in Prince George's County, Maryland — The American Northeast (Mid-Atlantic)
 

15-inch Rodman Smoothbore

 
 
15-inch Rodman Smoothbore Marker image. Click for full size.
By Craig Swain, March 1, 2008
1. 15-inch Rodman Smoothbore Marker
In need of some cleaning.
Inscription. Among the largest cannon used in the Civil War
Monumental in size, these two immense guns remain as sentinels ready to repel an attack on the Nation's capital. With their extended range and commanding location above the river, they were the key defensive feature of the fort. Perhaps because of their formidable weight, the guns (original armament of the fort) have not been moved since their installation in 1864.

Immobile as these huge guns may appear, a well drilled crew of 12 men could charge a gun with 40 pounds of black powder, load a 434-pound iron ball, 15 inches in diameter, and aim and fire once every 4 minutes.

Innovative technology in iron gun-casting made it possible to produce these 49,000 pdr. guns. They were named after Brig. Gen. Thomas J. Rodman, who perfected this new technology shortly before the Civil War.

These smoothbores were not noted for pinpoint accuracy. The three-mile range for such a large explosive projectile, however, was an impressive new defensive capability for the Civil War forts protecting Washington.
 
Marker series. This marker is included in the Defenses of Washington marker series.
 
Location. 38° 46.076′ N, 77° 1.759′ W. Marker is near Fort Washington, Maryland, in Prince
Rodman Gun Wayside image. Click for full size.
By Craig Swain, March 1, 2008
2. Rodman Gun Wayside
Using the map feature, in hybrid mode, these guns are visible on their mounts.
George's County. Marker can be reached from Fort Foote Road, on the right when traveling west. Click for map. Located inside the Fort Foote National Park. Marker is in this post office area: Fort Washington MD 20744, United States of America.
 
Other nearby markers. At least 8 other markers are within 2 miles of this marker, measured as the crow flies. Northwest Bastion (within shouting distance of this marker); The Defenses of Washington (within shouting distance of this marker); King's Depression Carriage (within shouting distance of this marker); Fort Foote (about 300 feet away, measured in a direct line); a different marker also named Fort Foote (about 700 feet away); Wasteland or Wetland? (approx. 1.3 miles away in Virginia); Colonial Fort (approx. 1.5 miles away in Virginia); Historic Jones Point (approx. 1.5 miles away in Virginia). Click for a list of all markers in Fort Washington.
 
More about this marker. The background of the marker is a depiction of a 15-inch Rodman Gun serviced by its crew.
 
Also see . . .
1. Fort Foote. National Park Service site providing a short history of the fort. (Submitted on May 6, 2008, by Craig Swain of Leesburg, Virginia.) 

2. Fort Foote Virtual Tour by Markers. (Submitted on May 7, 2008, by Craig Swain of Leesburg, Virginia.)
 
Categories. Forts, CastlesWar, US Civil
 
15-inch Rodman Smoothbore Marker image. Click for full size.
By Allen C. Browne, September 18, 2011
3. 15-inch Rodman Smoothbore Marker
15-inch Rodman Guns in Center Pivot Barbette Mounts image. Click for full size.
By Craig Swain, March 1, 2008
4. 15-inch Rodman Guns in Center Pivot Barbette Mounts
The center pivot barbette mountings allowed 360 degree traverse for these massive guns. Surprisingly, these weapons were so well balanced, very little effort could move the guns.
15-inch Muzzle image. Click for full size.
By Craig Swain, March 1, 2008
5. 15-inch Muzzle
Markings on the muzzle indicate this weapon is registry "No. 1" produced by Cyrus Alger and Company, of Boston Massachusetts. It was accepted for service in 1863, after an inspection by none other than Thomas Rodman himself. His initials, TJR, and the year are stamped on the muzzle. Finally the weight is indicated as 49,392 pounds.
Breech of Rodman Gun image. Click for full size.
By Craig Swain, March 1, 2008
6. Breech of Rodman Gun
The breech end of the Rodman gun shows two of the General's adaptations to improve the gun. First, guns of this size could not be easily elevated by the traditional hand screw systems. So the sockets seen here allowed a very simple handspike system to raise and lower the gun. Second, the groove around the breech, replacing the traditional knob and neck, provided lifting tackle a purchase to firmly move the gun. The "mushroom," as it is often called, was more durable.
Looking Down the Barrel of the Gun image. Click for full size.
By Craig Swain, March 1, 2008
7. Looking Down the Barrel of the Gun
The knob over the center of the gun was a front sight block. With most smoothbores, accuracy was more a function of crew persistence and luck.
15-inch Rodman Smoothbore image. Click for full size.
By Allen C. Browne, September 18, 2011
8. 15-inch Rodman Smoothbore
Close-up of image on marker
 
 
Credits. This page originally submitted on , by Craig Swain of Leesburg, Virginia. This page has been viewed 2,540 times since then and 36 times this year. Photos:   1, 2. submitted on , by Craig Swain of Leesburg, Virginia.   3. submitted on , by Allen C. Browne of Silver Spring, Maryland.   4, 5, 6, 7. submitted on , by Craig Swain of Leesburg, Virginia.   8. submitted on , by Allen C. Browne of Silver Spring, Maryland. This page was last revised on June 16, 2016.
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