North Waterfront in San Francisco City and County, California — The American West (Pacific Coastal)

Alcatraz Fire Power

Photographed By Joseph Alvarado

1. Alcatraz Fire Power Marker

Inscription. Alcatraz began as a U.S. Army fort, designed to defend San Francisco Bay against enemy attack. At the height of the Civil War, the fortified island held over 100 heavy cannon. The largest of these were the sleek “Rodman” guns on iron carriages. The Rodmans’ distinctive soda bottle shape reflected the pressures that built up inside the barrel during firing. Nicknamed after their inventor, Thomas Jackson Rodman, the guns’ design and careful manufacture made them very safe weapons to fire, an important feature at a time when many cannon blew up without warning. Rodmans ranged in size from 8-inch caliber guns up through 15-inch caliber models that weighed nearly 50,000 pounds.

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[#15-Alcatraz Fire Power]

(Marker Number 15.)

Topics. This historical marker is listed in these topic lists: Forts and Castles • Parks & Recreational Areas • War, US Civil.

Location. 37° 48.394′ N, 122° 24.255′ W. Marker is in San Francisco, California, in San Francisco City and County. It is in North Waterfront. Marker can be reached from

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The Embarcadero south of Bay Street, on the right when traveling north. The resin marker is mounted to a metal stand next to a replica Rodman Cannon on Alcatraz Landing. Touch for map. Marker is at or near this postal address: Pier 33, San Francisco CA 94133, United States of America. Touch for directions.

Other nearby markers. At least 8 other markers are within walking distance of this marker. Alcatraz Firepower (here, next to this marker); The 10-Inch Rodman (here, next to this marker); Indian Occupiers (a few steps from this marker); Military Schoolhouse (a few steps from this marker); The Post Exchange & Officers' Club (a few steps from this marker); Guardhouse & Sallyport Complex (a few steps from this marker); Industrial Buildings (a few steps from this marker); The Dock (a few steps from this marker). Touch for a list and map of all markers in San Francisco.

More about this marker. There is a small braille plaques on the lower left corner of the marker.
Inset Image:
The largest cannon on Alcatraz were 15-inch caliber like the one above. They could fire a 440-lb. cannonball nearly three miles. Courtesy: Bancroft Library

Also see . . .
1. The Man Behind the Rodman Gun. Historynet

"Although in the long run the gun was a technological dead end, the advances introduced by its designer, Brigadier General Thomas Jackson Rodman, revolutionized
Photographed By Joseph Alvarado, June 15, 2023

2. Alcatraz Fire Power Marker and Replica Rodman Cannon
gun-barrel production and propellant design."

(Submitted on July 18, 2023, by Joseph Alvarado of Livermore, California.)

2. Alcatraz's Defenses Revamped, 1869-1876. AlcatrazHistory.com

"The massive 15-inch calibre Rodman Cannons on Alcatraz used small cranes to hoist the solid cannonballs which could be shot at a range of 3-miles."

(Submitted on July 18, 2023, by Joseph Alvarado of Livermore, California.)

Replica Rodman Cannon image. Click for full size.

Photographed By Joseph Alvarado, June 15, 2023

3. Replica Rodman Cannon

Credits. This page was last revised on July 18, 2023. It was originally submitted on July 18, 2023, by Joseph Alvarado of Livermore, California. This page has been viewed 53 times since then and 17 times this year. Photos: 1, 2, 3. submitted on July 18, 2023, by Joseph Alvarado of Livermore, California.