15-Inch Rodman

In 1873 Fort Jefferson's armament was modernized to include six 15-inch Rodman smoothbore cannon and four 300-pounder rifled Parrott guns. Of the 141 guns listed at the fort when the garrison left in 1874, only those 10 remain here today. The other cannon, gun carriages and cannonballs were sold for scrap in 1900. The 15-inch Rodmans could fire a 432-pound solid projectile or a 330-pound exploding shell three miles, the distance from here to Loggerhead Key on the horizon to the west. The cannon were mounted on a center-pintle carriage so they could be rotated 360 degrees to fire at ships on any side of the fort as needed. The 15-inch Rodmans were eventually made obsolete by breech-loading steel rifles in the late 1800s. Six Rodmans, weighing 25 tons each, were left here because of their immense size. For over 100 years they lay in the sand on the fort's terreplein, or roof. In 2010 this cannon was mounted on a reproduction carriage and gun platform.