In accordance with his orders, Walke, on arriving off the mouth of the river, sent two light-draught gunboats, the Signal and Marmora, which made a reconnoissance twenty miles up, where they fell in with a number of torpedoes, one of which exploded near them. Having received their report, Captain Walke determined, as the river was rising, to send them up again with two of the heavy boats, the Cairo and Pittsburg, to cover them while they lifted the torpedoes. The ram Queen of the West also went with them.
These vessels left the main body at 8 A.M., December 12th. When the torpedoes were reached they began removing them, the two light-draughts in advance, the ram next, the two heavy boats bringing up the rear. While thus engaged the Marmora began firing musketry, and Lieutenant-Commander Selfridge, in the Cairo, pushed ahead to support her. It was found that she was firing at an object floating in the water, which turned out to be a torpedo that had already been exploded. The Marmora was then ordered to proceed slowly again, the Cairo following; but before the latter had gone her length two sharp explosions occurred in quick succession, one under the bow and one under the stern, the former so severe as to lift the guns from the deck. The ship was at once shoved into the bank, and hawsers run out to keep her from slipping off into deep water; but all was useless. She filled and sank in twelve minutes, going down in a depth of six fathoms, the tops of her chimneys alone remaining visible. The work of destroying the torpedoes was continued after the accident, in which no lives were lost. Thus, at the very beginning of operations, the flotilla was deprived of one of its best vessels, the first to go of the original seven.
The torpedoes by which the Cairo was sunk were merely demijohns filled with powder and ignited by a common friction primer rigidly secured inside. To the primer was fastened a wire passing through a water-tight cork of gutta percha and plaster of Paris. The first very primitive idea was to explode them by pulling from the shore, and it is possible that the first to go off near the light-draughts was thus fired. The matter was then taken in hand by a Confederate naval officer, who arranged them in pairs, anchored twenty feet apart, the wire leading from the primer of one to that of the other. Torpedoes had hardly yet come to be looked on as a respectable mode of warfare, especially by seamen, and the officer who laid these, and was looking on when the Cairo went down, describes himself as feeling much as a schoolboy might whose practical joke had taken a more serious shape than he expected.
The work of removing the torpedoes was continued by the boats under Lieutenant-Commander John G. Walker, of the Baron de Kalb, formerly the St. Louis. Two landing-places were at the same time secured. After the arrival of the admiral the work went on still more vigorously from the 23d to the 26th of December. A bend in the river was then reached, which brought the vessels under fire of the forts on Drumgoold's Bluff. Every step of the ground so far gained had been won under a constant fire of musketry, which the armored portion of the light-draught gunboats resisted, but their upper works were badly cut up. The batteries of the enemy being now only twelve hundred yards off, the flag-ship Benton took position to cover the lighter vessels, having to tie up to the bank because the wind blowing up stream checked the current and threw her across it. She remained in this position for two hours, receiving the enemy's fire and being struck thirty times, but without serious injury. Unfortunately her captain, Lieutenant-Commander William Gwin, a valuable officer, who had distinguished himself at Shiloh and in the fight with the Arkansas, was mortally wounded; having, in his anxiety to see how effective was the fire of the vessels, left the armored pilot-house, saying, with a noble rashness, that the captain's place was on his quarterdeck.
The army, 32,000 strong, under General W.T. Sherman, had arrived on the 26th, and landed on the low ground above the old mouth of the Yazoo, the gunboats occupying the sweep of river around them for a length of eight miles. Heavy rains had set in, making the ground almost impassable and causing the water to rise. After various preliminary operations the troops assaulted the works on the hills in front on the 29th, but the attack failed entirely. Sherman considered the works too strong to justify its renewal at the same point, but determined to hold his ground and make a night assault with 10,000 men higher up the river, upon the right of the Confederate works at Haines's Bluff, where the navy could get near enough to try and silence the batteries. Colonel Charles Rivers Ellet,[14] of the ram fleet, volunteered to go ahead with the ram Lioness and attempt to blow up a raft which was laid across the stream. Everything was ready on the night of the 31st, but a dense fog setting in prevented the movement.
The continued rains now rendered the position of the army dangerous, and it was re-embarked on the 2d of January. The enemy apparently did not discover the movement till it was nearly finished, when they sent down three regiments with field pieces to attack the transports, a movement quickly checked by the fire of the gunboats.
When Sherman's army was embarked, the transports moved out into the Mississippi and anchored five miles above Vicksburg, where General McClernand joined and assumed the chief command. Soon after his arrival he determined upon a movement against Fort Hindman, on the Arkansas River, fifty miles from its mouth. This point, better known as Arkansas Post, commanded the approach to Little Rock, the capital of Arkansas, but was specially obnoxious to the Union forces at this time, as being the base from which frequent small expeditions were sent out to embarrass their communications by the line of the Mississippi, from which it was but fifteen miles distant in a straight line. A few days before, the capture of the Blue Wing, a transport loaded with valuable stores, had emphasized the necessity of destroying a work that occupied such a menacing position upon the flank and rear of the projected movement against Vicksburg.
The admiral detailed the three ironclads, De Kalb, Louisville, and Cincinnati, and all the light-draught gunboats to accompany the expedition; the gunboats, on account of their low speed, being taken in tow by the transports. Passing by the mouth of the Arkansas, to keep the enemy as long as possible uncertain as to the real object of the movement, the fleet entered the White River and from the latter passed through the cut-off which unites it with the Arkansas.
On the 9th of January the army landed about four miles below the fort. This was a square bastioned work of three hundred feet on the side, standing on ground elevated above the reach of floods on the left bank, at the head of a horse-shoe bend. It had three casemates, one in the curtain facing the approach up the bend, and one in the face of the northeast and southeast bastions looking in the same direction. In each bastion casemate was a IX-inch, and in that of the curtain an VIII-inch shell-gun. These were the special antagonists of the navy, but besides them there were four rifled and four smooth-bore light pieces on the platform of the fort, and six similar pieces in a line of rifle-pits exterior to and above it. Some trenches had been dug a mile and a half below the fort, but they were untenable in presence of the gunboats, which enfiladed and shelled them out.
While the army was moving round to the rear of the fort the admiral sent up the ironclads to try the range, and afterward the light-draught Rattler to clear out the rifle-pits, which was done at 5.30 P.M. Hearing from General McClernand that the troops were ready, the Louisville, Lieutenant-Commander Owen; De Kalb, Lieutenant-Commander Walker, and Cincinnati, Lieutenant Bache, advanced to within four hundred yards of the work and opened fire; the Louisville in the centre, the De Kalb on the right and the Cincinnati on the left, each having one of the enemy's casemate guns assigned to it. The vessels fought bows on, three guns each; the odds being thus three guns afloat to one in casemate on shore, leaving the advantage by the old calculation, four to one, rather with the fort, without counting the light pieces in the latter. When the ironclads were hotly engaged the admiral brought up the light-draught vessels, with the Black Hawk and Lexington, to throw in shrapnel and light rifled shell. Later, when the battery was pretty well silenced, the Rattler, Lieutenant-Commander Watson Smith, was ordered to pass the fort and enfilade it, which he did in handsome style, suffering a good deal from the enemy's fire; when above, however, he became entangled in snags and was obliged to return. No assault was made this day by the army.