Dahlgren gun - St. Joseph, MI - Wikipedia Entries on Waymarking.com

The historical marker reads:
"On July 5, 1897 with great pride and effort the A.W. Chapman Post of the Grand Army of the Republic dedicated this gun and grounds to the memories of those who fought in the Civil War in defense of the flag. This 11 inch bore Dahlgren was built in 1864 at Hinkley, Williams & Co., Boston, Massachusetts for service in the Civil War. Cast hollow and bored out on a lathe this gun has a finished weight of 15,890 lbs. Using 15 lbs. of gunpowder this smoothbore cannon can hurl a 130 lb. exploding shell or 200 lb. solid shot over 2 miles. Removed from the U.S.S. Marion in 1876 this cannon' previous service is uncertain."

From Wikipedia:
"Throughout the 18th and early 19th century the primary ship to ship weapon were broadside guns firing solid shot. This all changed when the French Navy adopted a design of Col. Henri-Joseph Paixhans for a shell gun (canon obusier) of 22 cm (8.7-inch) capable of throwing a 59 lb. shell in a reasonably flat trajectory (Gardiner 1992, p. 154). The U.S. Navy followed suit adopting the 8-inch, 63 cwt. Paixhans-style shell gun in 1841. Dahlgren was determined to design a new generation of shell gun that would be capable of firing explosive shells at higher velocity and greater range. They would also have the capacity to effectively fire solid shot. The ability to fire sold shot would become increasingly important as armored warships appeared on the scene. All of the Dahlgren shell guns were cast in iron, had a distinctive soda bottle shape and all but two had an elevating screw running through the cascabel. Although some Dahlgren shell guns were tested to failure, no Dahlgren shell gun burst during service, a notable distinction for the time. All of the Dahlgren shell guns in service fired shot, shell, shrapnel, canister, and (with the exception of the XV-inch shell gun) grape-shot.

XI-inch Dahlgren shell gun 465 were cast at Alger; Builders; Fort Pitt; Hinkley, Williams & Co.; Portland Locomotive Works; Seyfert, McManus & Co.; Trenton Iron Works; and West Point foundries between 1856 and 1864. This is the only Dahlgren gun to have been designed both with and without a muzzle swell. The gun was typically mounted on a pivot or in a turret on a monitor. When mounted in a turret, the crew for an XI-inch Dahlgren was 7 including powdermen. The crew for the gun when mounted on a pivot was 24 men and a “powderman.” XI-inch Dahlgrens were carried on Neosho, Marietta, Casco, Milwaukee, and (1 XI-inch and 1 XV-inch short) class monitors as well as the original USS Monitor. The USS Kearsarge, USS Powhatan, and many other conventional ships carried XI-inch Dahlgrens on pivot mounts. A few larger river gunboats, such as the USS Tuscumbia and USS Indianola also carried XI-inch Dahlgrens."