USS Marmora was a sternwheel steamer that served in the Union Navy from 1862 to 1865, during the American Civil War. Built in 1862 at Monongahela, Pennsylvania, as a civilian vessel, she was purchased for military service on September 17 and converted into a tinclad warship. Commissioned on October 21, the vessel served on the Yazoo River beginning the next month. She encountered Confederate naval mines on the Yazoo on December 11, and was present the next day when the ironclad USS Cairo was sunk by two mines. After further service on the Yazoo during the Battle of Chickasaw Bayou in late December, Marmora was assigned in January 1863 to a fleet that was preparing to operate against Confederate Fort Hindman, but was not present when the fort surrendered on January 11.
From February to April, Marmora participated in the Yazoo Pass expedition, and in June burned and destroyed the settlements of Eunice and Gaines Landing, Arkansas, after Union vessels were fired on by Confederate troops. In August, the tinclad participated in some activities on the White River while the Little Rock campaign was beginning, and patrolled on the Mississippi River late that year. In February 1864, she participated in another movement up the Yazoo River, and fought in the Battle of Yazoo City on March 5. Continuing to serve on the Mississippi River, Marmora was declared surplus in May 1865 and was put in reserve status at Mound City, Illinois, the next month. On July 7, she was decommissioned, and was sold at public auction on August 17. Nothing further is known about Marmora after her sale.
Construction and characteristics Marmora was built in 1862 at the shipyard of William Latta in Monongahela, Pennsylvania. She was built for ship captain James McDonald, who had previously operated another ship with the same name. She was also known as the Marmora No. 2, and the name originated with the island of Marmara. She had a tonnage of 207 tons, was long, had a draft of when "deeply loaded", and had a beam of . A sternwheel steamer, her paddle wheel was in diameter, with paddles that were long. Propulsion was provided by two steam engines, which had cylinder diameters of and a stroke of . Steam was provided by two Watson and Monroe boilers. Each boiler had three and three flues. Marmora had a top speed of , although this was reduced to when going upstream.
McDonald used Marmora several times, including transporting Union Army troops down the Kanawha River in August. At that time she was also in use for transporting passengers and freight, running between Pittsburgh, Pennsylvania, and Cincinnati, Ohio. With the Civil War ongoing, the Union Navy was seeking to increase the number of ships it operated, and the navy purchased Marmora for military use on September 17, at a cost of $21,000, () from C. Brennan, William Nelson, and James McDonnell. The steamer was converted into a tinclad warship. For tinclad conversions in general, this was a process that involved arming the ship, installing a wooden casemate that was at least partially covered with thin iron armor, replacing the pilothouse with a new armored one, reinforcing decks and internal beams, and generally removing the texas. Tinclad warships were used to patrol rivers, protect and escort other vessels, and sometimes act as naval support for military actions.
Marmora was assigned the identification number 2; these numbers were painted onto the pilothouses of the tinclads beginning in June 1863. She was commissioned into the Union Navy on October 21, 1862, at Carondelet, St. Louis. Over the course of her military service, her armament varied. Initially, she was armed with two 12-pounder rifled cannons and two 24-pounder guns. In June 1864, four 24-pounder guns were added to her armament, which consisted of eight 24-pounder guns as of the following December. As of March 31, 1865, she was reported to have been armed with two 12-pounder guns and six 14-pounders. Along with USS Signal, Marmora was one of the first purpose-converted tinclads in the Union Navy.
Service history Vicksburg campaign Marmora left Carondelet for Cairo, Illinois, on October 22, 1862, under the command of Acting Volunteer Lieutenant Robert Getty. In November, Union Army Major Generals Ulysses S. Grant and William T. Sherman, along with Acting Rear Admiral David Dixon Porter, decided that the Union Navy would operate against Confederate forces along the Yazoo River, in conjunction with the Vicksburg campaign. Porter's command was known as the Mississippi Squadron. On November 21, Captain Henry A. Walke received orders to move with a naval force from Helena, Arkansas, to the mouth of the Yazoo. Marmora was at Cairo at this time, and was ordered to join Walke. The vessel reached Helena on November 24, and left for the mouth of the Yazoo the next day along with Signal and the ironclad USS Carondelet; the three vessels were joined by the timberclad USS Lexington on November 26. The movement down the Mississippi River was conducted only during the daytime due to low water levels.
During the movement, Marmora had her first combat, destroying several barges at Lake Providence, Louisiana, and later destroying a flatboat and capturing two skiffs. On November 28, Walke's flotilla reached Milliken's Bend, Louisiana, where he sent part of the crew of Marmora on a tugboat, USS Laurel, on a scouting mission. The scouting group was fired on by Confederate guerrillas on the shore, and Acting Ensign H. H. Walker of Marmora was wounded. The next day, Walke's ships reached the mouth of the Yazoo, and Marmora and Signal were sent to scout up the river, accompanied by 20 men and a gunner from Carondelet, as the river level was too low for navigation by the larger ships. The scouting force upriver began at about 10:00am, and around noon, encountered Confederate cavalry and a picket station. The Confederate cavalry fled after firing on the vessels and Marmora destroyed the picket station with cannon fire. A minor skirmish occurred with Confederate forces from the mouth of the Yazoo at a ferry site, but the vessels continued for about another , until they sighted Confederate fortifications on Drumgould's Bluff. The vessels took care to avoid any fighting with the Confederate batteries, and returned to Walke's main force at around 4:00pm.
Sinking of USS Cairo
Several Union Navy naval rams arrived at the mouth of the Yazoo in early December 1862, including USS Queen of the West. Marmora helped refloat Queen of the West after the latter vessel ran aground on December 5. Marmora made multiple trips into the Yazoo to perform depth sounding. On December 11, Marmora and Signal were sent back up the Yazoo to scout the Confederate fortifications upriver. Walke had been informed by an escaped slave that the Confederates were erecting a barricade in front of the batteries, and wanted to verify that information. While in sight of the Confederate fortifications, the two ships noticed naval mines floating in the river. One of the men aboard Marmora shot one with a musket, resulting in an explosion that shook the entire ship, despite her being at least from the mine. While returning to Walke, Marmora and Signal were fired on by Confederate troops on the riverbank. Getty informed Walke that Marmora and Signal could clear the mines from the river if accompanied by larger vessels that could provide covering fire against any Confederate troops on the riverbanks; the water level in the Yazoo had risen enough to accommodate larger vessels.
The next day, Marmora, joined by Signal, Queen of the West, and the ironclads USS Cairo and USS Pittsburgh, moved up the Yazoo to remove the mines. Marmora and Signal were tasked with destroying the mines, with all of the ships' commanders instructed to avoid bringing their ships close to the mines. The expedition entered the Yazoo at around 8:00am, and at either 10:00am or 11:00am met a skiff containing an African American and a white plantation overseer. The overseer admitted to having knowledge of the location of the mines and as a result was arrested. The vessels continued ahead to where the mines were. Those on Cairo heard men from Marmora shooting at objects in the river and continued ahead thinking the tinclad was under assault. Both Cairo and Marmora put small boats into the water to investigate the mines, which were found to be connected to the shore by wires. Cairo and Marmora began to maneuver after launching the boats, and the Confederate batteries on Drumgould's Bluff fired on the vessels at long range. Cairo then struck two mines and quickly sank. None of the crew of Cairo were killed, and they were picked up by the other Union vessels.
Chickasaw Bluff and Fort Hindman
The surviving Union vessels returned to Walke's main force. Upon their return, the commander of Cairo was told to put his crew on Marmora and take her up the Mississippi River to Cairo, where he was to report to Porter. Marmora met Porter and the gunboat USS Black Hawk on December 17 while moving upriver. Porter elected to not open a court of inquiry against the commander of Cairo, and ordered the mine clearing to be completed. The crewmen of Cairo were landed at Cairo on December 18. Marmora then helped other Union vessels clear the mines out of the river. The naval vessels also probed along the Yazoo in support of Union Army movements in the area. On December 27, Sherman landed army troops in front of Chickasaw Bluff, while Marmora joined six other naval vessels in advancing upriver against Drumgould's Bluff. The naval vessels were to cover Sherman's left flank and draw Confederate attention away from the main Union assault. The flotilla fought against the Confederate batteries, but Marmora remained in the rear and was not struck by fire. While Marmora did join the firing, her shooting, like that of the other vessels, accomplished little.
The next morning, Marmora and the gunboat USS Forest Rose went up the Old River towards the False River and shelled the riverbanks. Forest Rose ran aground, but Marmora freed her, and the two vessels returned to the rest of the Union fleet in the early afternoon. On December 29, Porter's gunboats provided supporting fire, but Sherman's men were repulsed in the Battle of Chickasaw Bayou. Marmora spent part of that day on another expedition into the Old River, this time accompanied by the tinclad USS Romeo. Sherman's men withdrew after the repulse. After the defeat at Chickasaw Bayou, Union leadership used the capture of a Union transport, Blue Wing, as justification for a strike on a Confederate position at Fort Hindman in Arkansas. Marmora was part of the Union fleet that participated in the resulting campaign in January 1863. On January 4, Porter reorganized his force, and Marmora was assigned to a division led by Lieutenant Commander Watson Smith. Porter's ships began the movement towards Fort Hindman that same day. Three days later, a plan for naval activity against the fort was formed. Marmora was to advance upriver with several other ships, but she instead found herself spending the day towing Carondelet, which was low on coal, up to Helena. Marmora then arrived off of the mouth of the White River on the evening of January 9, towing two barges of coal. Fort Hindman surrendered on January 11. On January 14, Marmora was ordered by Porter to return to the rest of the fleet. Three days later, she steamed up the Arkansas River, reached the site of the Confederate fort, and sent a party ashore to help destroy it.
Yazoo River operations and burning of Eunice