The Battle of Grand Gulf was fought on April 29, 1863, during th: At 7:00 a.m. on April 29, seven Union Navy ironclads led by Porter moved down the river from Hard Times Landing towards the positions at Grand Gulf.  Roughly 30,000 Union infantry were in the Hard Times Landing area, of whom about 10,000 were on transports. The men on the transports, which had pulled away from the landing and were sheltered behind a spit of land named Point Coffee, were intended to cross the river and occupy Grand Gulf once the Confederate batteries were subdued.[34][37] Porter instructed his ironclad commanders to take care to avoiding running aground in shallow water. Men from detachments of the 58th Ohio Infantry Regiment and the 29th Illinois Infantry Regiment were stationed on board the ironclads to serve as marines and, if necessary, as a landing force.[38] Of Porter's ironclads, USS Pittsburgh was in the lead, followed by USS Louisville, USS Carondelet, and USS Mound City.  A second wave composed of USS Benton, USS Tuscumbia, and USS Lafayette followed. A total of 81 cannons were carried by these vessels, compared to 13 in the Confederate positions.  The naval forces also had the advantage in size of artillery: the majority of the Confederate guns were 30-pounders or smaller, as opposed to the median Union piece being a 42-pounder. The ironclads first targeted Fort Cobun, then Pittsburgh, Louisville, Carondelet, and Mound City moved to focus on Fort Wade; the other three remained focused on Fort Cobun.  After passing Fort Cobun, the ships turned so that their bows pointed upstream.[39]  The lead Union vessels opened fire at about 7:50 a.m., and Fort Cobun responded about 25 minutes later.[40]  Currents in the river caught some of the Union vessels, forcing them to spin in circles while the Confederate fired upon them.[41]  After the shooting started, the 12th Arkansas Sharpshooter Battalion was moved forward from a reserve position into rifle pits near Fort Cobun.[42]