Meanwhile Commander Henry Walke had volunteered to take his boat, the Carondelet; and, on March 30th, Flag-officer Foote gave him permission to make the attempt on the first dark night. The morning of April 4th was a busy time on the Carondelet. The deck was covered with heavy planks, surplus chains were coiled over the most vulnerable parts of the boat, an eleven-inch hawser was wound around the pilot-house as high as the windows; barriers of cordwood were built about the boilers. After sunset, the atmosphere became hazy and the sky overcast. Guns were run back, ports closed, and the sailors armed to resist boarders. Directions were given to sink the boat if it became liable to fall into the enemy's hands. At dusk, twenty sharpshooters from the Forty-second Illinois came aboard to be ready to aid the crew in resisting boarders. After dark, a coal-barge laden with baled hay was fastened to the port side of the boat. At ten o'clock the moon had gone down and a storm was gathering. The Carondelet cast loose and steamed slowly down the river. The machinery was adjusted so as to permit the steam to escape through the wheel-house, and avoid the noise of puffing through the pipes. The boat glided noiseless and invisible through the darkness. Scarcely had it advanced half a mile when the soot in the chimneys caught fire, a blaze shot up five feet above the smoke-stack. The flue-caps were opened, the blaze subsided, and all was yet silent along the shore. The soot in the smoke-stacks not being moistened by the steam, which was now escaping through the wheel-house, became very inflammable. Just as the Carondelet was passing by the upper battery--the redan--the treacherous flame again leaped from the chimneys, revealing and proclaiming the mission of the boat. Sentries on the parapets on shore fired, guards turned out, rockets darted skyward; the heavy guns opened fire; and the brooding storm broke forth, the lightning and thunder above drowning the flashes and war below. The lightning revealed the position of the gunboat, but it also disclosed the outline of the shore, enabling the pilots to steer with certainty. The boat was pushed near to the Tennessee shore and to the island, and put to its greatest speed. Impeded by the barge in tow, its greatest speed was slow progress, and for half an hour the gunners in the batteries watched the black night to see the hurrying Carondelet shot for an instant out of the darkness at every lightning flash. Beyond the batteries lay the floating battery, carrying nine guns, which had been driven from its moorings the day before by the heavy fire of the fleet. A light on the floating battery marked its position. A few shots left it, but it evinced no eagerness to join in conflict. The Carondelet, unharmed, untouched, fired the agreed signal, and fleet and army knew at midnight the passage was a success.