Farragut now felt that his personal presence was no longer required above Port Hudson, and returned to New Orleans by one of the bayous; leaving Commodore Palmer with the Hartford, Albatross, Estrella, and Arizona to maintain the blockade above until Porter was ready to assume the entire charge. The Hartford, however, did not come down till after the surrender of Port Hudson, two months later.
After the capture of Alexandria and the dispersal of the enemy in that quarter, General Banks moved down with his army to Simmesport, on the Atchafalaya Bayou, five miles from the Red River, and thence across the Mississippi at Bayou Sara, five or six miles above Port Hudson. General Augur of his command at the same time moved up from Baton Rouge. The two bodies met on the 23d of May, and Port Hudson was immediately invested. An assault was made on the 27th, but proved unsuccessful, and the army settled down to a regular siege. A battery of four IX-inch shell-guns from the navy was efficiently served throughout the siege by a detachment of seamen from the Richmond and Essex under Lieutenant-Commander Edward Terry, executive officer of the former vessel. The Essex, Commander Caldwell, and the half dozen mortar-schooners under his orders maintained a constant bombardment and succession of artillery fights with the river batteries of the enemy, being exposed to the fire of four VIII-and X-inch columbiads and two heavy rifles. Between the 23d of May and 26th of June Caldwell estimated that one thousand shot and shell had been fired at him from these guns. During these daily engagements the Essex was hulled twenty-three times, besides being frequently struck above her decks, and had received severe injury. The mortar-schooners also came in for their share of hard knocks, and their captains were all specially commended both by Caldwell and Farragut.
On the 15th of May Porter went to the Yazoo and there awaited news from the army. On the 18th heavy firing in the rear of the city assured him of Grant's approach. That afternoon the advance of Sherman's corps came in below Snyder's Bluff, between the city and Haines's Bluff. The works at the latter point had been abandoned the evening before on the approach of the army; a small party only being left to destroy or remove whatever they could. Upon the appearance of the troops the admiral sent up a force of gunboats under Lieutenant-Commander K.R. Breese, whereupon the party ran off, leaving everything in good order. The works mounted fourteen heavy guns, VIII- and X-inch smooth-bores, and VII½-inch rifles; the carriages of these were burned, as were the Confederate encampments, and the magazines blown up. Porter now received letters from Grant, Sherman, and Steele, informing him of the entire success of the campaign in the rear of Vicksburg, and asking that provisions might be sent up, the army having lived off the country almost entirely during a fortnight of constant marching and fighting. Lieutenant-Commander J.G. Walker in the De Kalb was sent up to Yazoo City with sufficient force to destroy the enemy's property which he might find, and the gunboats below Vicksburg were moved up to fire on the hill batteries, an annoyance to the garrison which they kept up off and on during the night. On the 19th six mortar-boats were got into position, with orders to fire night and day as rapidly as possible.
Grant, having completed the investment of Vicksburg, sent word on the evening of the 21st that he intended to make a general assault upon the enemy's works at 10 A.M. the following day, and asked that the fleet might shell the batteries from 9.30 to 10.30. Porter complied by keeping up his mortar fire all night and sending up the gunboats to shell the water batteries, and other places where he thought the enemy might find rest. At 7 A.M. the next day the Mound City, followed at eight by the Benton, Tuscumbia, and Carondelot, moved up abreast the lower end of the canal, opening upon the hill batteries; then they attacked the water batteries, the duel between them and the ships at a range of four hundred and fifty yards being maintained incessantly for two hours. The Tuscumbia proved, as before, too weak to withstand such close action and had to drop down. The admiral wrote that this was the hottest fire that the gunboats had yet endured, but the water batteries having little elevation, the ships contended on more even terms than at Grand Gulf, and fighting bows on, received little damage.
The fire was maintained for an hour longer than Grant had asked, when the vessels dropped out of range, having lost only a few wounded. The assault of the army was not successful and regular siege operations were begun. Vicksburg and Port Hudson, the two extremes of the Confederate line, were thus formally invested by the 27th of May. On that day, Porter, having received a request from Grant and Sherman to try whether the enemy had moved from the batteries the guns on their extreme left, as they had from many of the other hill batteries, sent down the gunboat Cincinnati, Lieutenant George M. Bache, to draw their fire if still there; and, if possible, to enfilade the enemy's rifle-pits in that quarter and drive them out. The Cincinnati started from the upper division of the squadron at 7 A.M.; the vessels of the lower division, Price, Benton, Mound City, and Carondelet, steaming up at the same time to cover her movement by engaging the lower batteries, which might have played upon her. General Sherman took a position upon a hill at the extreme right of the Union lines, overlooking the river, so as to see the affair and take advantage of any success gained by the Cincinnati's attack. The gunboat, protected as usual by logs and hay, came within range shortly after nine o'clock, and the enemy began firing rapidly from all their batteries, the guns whose position had been doubted proving to be in their old place. When abreast the position assigned her for enfilading the rifle-pits the Cincinnati rounded to, and as she did so a shot pierced her side and entered the shell-room, capsizing nearly all the boxes on one side of the alley. As she came to with her head up stream, another ball entered the shell-room below the water-line, and a third pierced her stern, always the weakest part of these vessels, going into the magazine, also below the water-line, flooding it instantly and causing the vessel to fill rapidly. A heavy shot drove through the pilot-house, and shortly afterward the starboard tiller was carried away. The plunging fire of many big guns, concentrated on a single vessel, wrought great injury in a short time; penetrating her light deck, five of her guns were disabled by it. All three flag-staffs were shot away, carrying the colors down with them; upon which, a quartermaster, Frank Bois by name, went out and nailed a flag to the stump that was left of the forward staff. Finding the vessel must sink, Lieutenant Bache kept running up stream, hugging the east bank to be as far as possible out of the enemy's range, and about ten minutes before she went down sheered in, ran out a hawser, and a plank by which the wounded were landed. Unfortunately the men who went ashore with the hawser did not secure it properly, the boat began drifting out into the stream, and the officers and crew had to swim for their lives. She sank in three fathoms of water within range of the enemy's batteries, the second to go down of the seven first built. The loss was 5 killed, 14 wounded, and 15 missing; supposed to have been drowned.
The detached expedition to Yazoo City, under Lieutenant-Commander Walker, had returned on the evening of the 23d. On the approach of the vessels, the Confederates had set fire to the navy yard and three steamers on the stocks building for ships of war, one a very large vessel, 310 feet long by 70 feet beam and intended to carry 4½-inch plating. All that had not been destroyed or removed by the enemy the gunboats finished, the loss being estimated at two million dollars. An attack was made upon the gunboats at a bend of the river by a small force of riflemen with three field pieces, but was repelled without trouble, one man only being killed and eight slightly wounded. The morning after their return the same vessels were again sent up. One of the light-draughts, the Signal, met with the curious accident of knocking down her smoke-stacks, an incident which again illustrates the peculiar character of this bayou warfare. Sending her back, and leaving his own vessel, the De Kalb, to follow as rapidly as possible, Walker pushed on with the Forest Rose, Linden, and Petrel to within fifteen miles of Fort Pemberton, by which the Yazoo Pass expedition had been baffled. Here four fine steamers had been sunk on a bar, stopping farther progress. Having no means of raising them, they were fired and burned to the water's edge. The vessels then passed down the Yazoo, burning a large saw-mill twenty-five miles above Yazoo City, till they came to the Big Sunflower River. They ascended this stream one hundred and eighty miles, branch expeditions being sent into the bayous that enter it, destroying or causing the destruction of four more steamers. Transportation on the Yazoo by the Confederates was now broken up below Fort Pemberton, while above it a few steamers only remained.
From this time until the surrender of Vicksburg little occurred to vary the routine siege operations. Thirteen heavy cannon, from IX-inch to 32-pounders, were landed from the fleet to take their place in the siege batteries, in charge, at different points of the lines, of Lieutenant-Commander T.O. Selfridge, and Acting-Masters C.B. Dahlgren and J.F. Reed; and as many officers and men as could be spared were sent with them. Three heavy guns, a X-inch, IX-inch, and 100-pound rifle, under the command of Lieutenant-Commander F.M. Ramsay, of the Choctaw, were placed in scows close to the point opposite the town, but where they were protected by the bank, enfilading the batteries and rifle-pits on the enemy's left, against which the Cincinnati had made her unsuccessful attack. The gunboats below were constantly under fire and the mortars steadily shelling. On the 19th of June Grant notified the admiral that he intended to open a general bombardment at 4 A.M. the following day and continue it till 10 A.M. The lower division, the scow battery, and the mortars joined in this, shelling the hill batteries and the city, but no reply was made by the enemy from the water front.
The great service of the navy during the siege was keeping open the communications, which were entirely by the river from the time that Sherman's corps reached Snyder's Bluff. The danger of Vicksburg thrilled from the heart of the Confederacy through every nerve to its extremities. It was felt that its fall would carry down Port Hudson also, leave the Mississippi open, and hopelessly sever the East and West. Every man, therefore, that could be moved was in motion, and though the enemy had no vessel on the river, the banks on either side swarmed with guerillas, moving rapidly from spot to spot, rarely attempting to attack any body of troops, but falling back into the interior and dispersing when followed up. Provided with numerous field pieces, they sought to cut off the transports carrying reinforcements and the steamers carrying supplies. The tortuous course of the stream in many places enabled those who knew the ground to move rapidly across the country and attack the same vessel a second time if she escaped the first assault. On several occasions batteries were built, and a large force attempted the destruction of transports. From these dangers the navy was the only, as it was the best protection. The long line from Cairo to Vicksburg was patrolled by the smaller class of gunboats, and, thanks to their skilful distribution and the activity and courage of the individual commanders, no serious interruption of travel occurred. One steamer only was badly disabled and a few men killed or wounded.
On the 4th of July, 1863, Vicksburg surrendered, and on the 9th the garrison of Port Hudson also laid down its arms. The Mississippi was now open from Cairo to the Gulf, and the merchant steamboat Imperial, leaving St. Louis on the 8th, reached New Orleans on the 10th of this month without molestation.
The Navy Department now directed that the command of the river as far down as New Orleans should be assumed by Porter, Farragut to confine himself henceforth to the coast operations and blockade. Toward the end of July the two admirals met in New Orleans, and, the transfer having been made, Farragut sailed on the 1st of August for the North to enjoy a short respite from his labors. Porter then returned to Cairo, where he at once divided the long line of waterways under his command into eight districts,[19] of which six were on the Mississippi. The seventh extended on the Ohio from Cairo to the Tennessee, and thence through the course of the latter river, while the eighth embraced the upper Ohio and the Valley of the Cumberland. Each district had its own commander, who was responsible to the admiral, but was not to interfere with another unless in case of great need. For the present all was quiet, but there were already rumors of trouble to come when the enemy should recover from the stunning blows he had just received.