Fort Independence Boston, Ma

History of Fort Independence


Cannons and Mortar

8″ Mortars

The mortar pictured below is at the Fort at Front V, is an 8″ siege mortar model made of cast iron in 1861. The mortar was placed on a wooden bed to quickly and easily move, assemble, or disassemble. Nearly all mortars were fired at 45-degree angle and at such angle the average range of this weapon was 1,200 yards. The average weight of the 8″ siege mortars was 1,010 pounds, and each projectile weighed 44.5 pounds.

The mortar’s purpose was to fire direct high plunging “vertical” fire onto enemy ships and troops. Troops could use these weapons to fire at close range at smaller ships and troops who had evaded larger cannons

Civil War Siege Gun located Front V of Fort

Rodman Gun

15′ Rodman Gun was 15 feet and 10 inches long and weighed 49,090 pounds. A 50-pound powder charge would fire a 440-pound solid shot or a 352-pound shell up to three and a half miles away. It had a smoothbore barrel loaded from the front using a special crane and had a standard crew of eleven to fourteen men to operate.

Each battery on the ramparts had an independent magazine that stored powder, fuses, cartridges, and other volatile explosives. The magazine were positioned nearby so that the crew could maintain a rapid fire. Each magazine was buried beneath an earthen cover, with heavy wooden doors always closed to prevent a premature explosion.

Rodman Gun Located in Bastion A 

20 Pound Parrot Rifles

On the parade grounds at the Fort are two small cannons known as 20-pound Parrott rifles. These are examples of the improvement in weaponry during the Civil War. The upgrade from smoothbore barrels to rifled barrels in heavy weapons significantly improved the cannons’ accuracy and power. Loading from the cannon’s rear made the loading process much more accessible, quicker, and safer to fire.

Robert Parker Parrott graduated from West Point in 1824. He was a First Lieutenant at the Fort with the Third Artillery from 1831 to 1834. He became a specialist in artillery, and by 1861, he had perfected the rifled cannon to excellent quality and had improved its ease of manufacturing and reliability of firing the weapons. The new guns were cast iron and had a large wrought iron reinforcing band overlaid on the breech to give them additional strength. Robert Parrot patented his new gun in 1861.

During the War of 1812, cannon weaponry was not robust or accurate enough to destroy a granite fort. With this advancement in weaponry during the Civil War, defensive forts of this type became obsolete.

The cannons shown below are loan Peabody Essex Museum to Castle Island Association.

20 Pound Parrot Rifles located on Parade Ground

Resources used for this Article:

Castle Island and Fort Independence book by William Reid.

This book can found at Boston Public Library or puchased thru Castle Island Assocation.

Great resourece on Robert Parker Parrot , here is more information him from Dartmouth Library.