nine o'clock in the morning
Porter disguised them with mud and the branches of trees , so that they could not be readily distinguished from the river banks , being moored under cover of the woods on the bank just below Fort Jackson . The stratagem was successful ; his vessels were moored where he wished to have them , the nearest being two thousand eight hundred and fifty yards from Fort Jackson , and three thousand six hundred and eighty from Fort St. Philip . `` On the opposite side of the river , and a little farther from the forts , Porter had his six remaining vessels stationed , screening them also with willows and reeds , and mooring them under cover of the woods to conceal their true character . `` On the 18th of April , before nine o'clock in the morning , the attack was begun by a shot from Fort Jackson , then , as soon as Porter was ready , the _ Owasco _ opened fire , and the fourteen mortar boats concealed by the woods , also the six in full sight of the forts , began their bombardment . `` The gun-boats took part in the conflict by running up and firing heavy shells when the mortars needed relief . Porter was on the _ Harriet Lane _ , in a position to see what was the effect of the shells , and direct their aim accordingly . `` The fight went on for several days , then Farragut , deeming there was small prospect of reducing the forts , prepared to carry out another part of his instructions by running past them .