The Marietta-class monitors were part of a large program of armored ships ordered after the Battle of Hampton Roads caused the navy to favor monitors over the previous casemate ironclads of the . They were built to gain control of the Mississippi River and its many tributaries.[1]
The original plans for the Marietta-class ships resembled the river monitor in many ways. The gun turret was at the bow and they had a deckhouse aft. There were also twin smokestacks similar to the Mississippi River steamboat designs. The original plans also called for a forward, pyramidal pilothouse, similar to the one on, however it is believed that the pilothouse was moved to the top of the turret before construction was completed. The Marietta-class ships were 177feet long overall. They had a beam of 50feet and a draft of 5feet. They displaced 479LT. The ships had four steam boilers powering two western steamboat-type engines that drove a single propeller.[2] [3] The Marietta-class ships had a maximum speed of and they carried a maximum of 150LT of coal.[4]
The ships' main armament consisted of two smoothbore, muzzle-loading 11adj=onNaNadj=on Dahlgren guns mounted in a single gun turret.[5] Each gun weighed approximately . They could fire a 136lb shell up to a range of at an elevation of 15°.[6] The turret and the pilothouse were protected by 6inches of wrought iron armor while the deck and hull had 1.25inches of armor.[5]
The contract for the two ships was awarded to Tomlinson and Hartupee Co. on 16 May 1862. Construction was at their yard in Pittsburgh, Pennsylvania. Progress was slow, delayed by labor shortages and changes by the navy. The US government allocated $188,000 each for the construction of Marietta and Sandusky, but the final cost rose to $235,039 after charges for extra work.[7]
Marietta was laid down in 1862, launched on 4 January 1865 and completed 16 December 1865.[2] "She was accepted by the Navy on 25 April 1866. She was never commissioned. Soon after her acceptance Marietta was laid up at Mound City, Illinois. Renamed Circe on 15 June 1869, the gunboat carried that name only until 10 August, when she was again named Marietta. Remaining at Mound City, Marietta was sold 12 April 1873 to David Campbell"[8] for $16,000.[9]
Sandusky was launched in mid-January 1865; "she was not completed until 26 December 1865, and was accepted by the Navy on 25 April 1866. Never commissioned, she was renamed Minerva on 15 June 1869; but resumed the name Sandusky on 10 August 1869. The monitor was sold at Mound City, Illinois, on 17 April 1873 to David Campbell"[10] for $18,000.[9]