General Duncan reported that, on the 27th of March, he was informed by Lieutenant-Colonel Higgins, commanding Forts Jackson and St. Philip, of the coast-defenses, which were under his (General Duncan's) command, that the enemy's fleet was crossing the bars, and entering the Mississippi River in force; whereupon he repaired to Fort Jackson. After describing the condition of the forts from the excess of water and sinking of the entire site, as well as the deficiency of guns of heavy caliber in the forts, he proceeds:
"It became necessary in their present condition to bring in and mount, and to build the platforms for, the three ten-inch and three eight-inch columbiads, the rifled forty-two-pounder, and the five ten-inch seacoast mortars recently obtained from Pensacola on the evacuation of that place, together with the two rifled seven-inch guns temporarily borrowed from the naval authorities in New Orleans. It was also found necessary to repair the old water-battery to the rear of and below Fort Jackson, which had never been completed, for the reception of a portion of these guns, as well as to construct mortar-proof magazines, and shell-rooms within the same."
One of the seven-inch rifled guns borrowed from the navy was subsequently returned, so that, when the forts were attacked, the armament was one hundred and twenty-eight guns and mortars.
The garrisons of Forts Jackson and St. Philip were about one thousand men on December 5, 1861; afterward, so far as I know, the number was not materially changed.
The prevailing belief that vessels of war, in a straight, smooth channel, could pass batteries, led to the construction of a raft between the two forts which, it was supposed, would detain the ships under fire of the forts long enough for the guns to sink them, or at least to compel them to retire. The power of the river when in flood, and the drift-wood it bore upon it, broke the raft; another was constructed, which, when the drift-wood accumulated upon it, met a like fate. Whether obstructions differently arranged—such as booms secured to the shores, with apparatus by which they could be swung across the channel when needful, or logs such as were used, except that, being unconnected together, but each separately secured by chain and anchor, they might severally yield to the pressure of the driftwood, sinking, so as to allow it to pass over them, and, when relieved of the weight, rising again—or whether other expedient could have been made permanent and efficient, is a problem which need not be discussed, as the time for its application has passed from us.
The general plan for the defense of New Orleans consisted of two lines of works: an exterior one, passing through the forts near the month of the river, and the positions taken to defend the various water approaches; nearer to the city was the interior line, embracing New Orleans and Algiers, which was intended principally to repel an attack by land, but also, by its batteries on the river-bank, to resist approach by water. The total length of the intrenchments on this interior line was more than eight miles. When completed, it formed, in connection with impassable swamps, a very strong line of defense. At the then high stage of the river, all the land between it and the swamps was so saturated with water, that regular approaches could not have been made. The city, therefore, was at the time supposed to be doubly secure from a land-attack.
In the winter of 1861-'62 I sent one of my aides-de-camp to New Orleans to make a general inspection, and hold free conference with the commanding General. Upon his return, he reported to me that General Lovell was quite satisfied with the condition of the land-defenses—so much so as to say that his only fear was that the enemy would not make a land-attack.
Considered since the event, it may seem strange that, after the fall of Donelson and Henry, and the employment of the enemy's gunboats in the Tennessee and Cumberland, it was still generally argued that the danger to New Orleans was that the gunboats would descend the Mississippi, and applications were made to have the ship Louisiana sent up the river as soon as she was completed.
The interior lines of defense mounted more than sixty guns of various caliber, and were surrounded by wide and deep ditches. On the various water approaches, including bays and bayous on the west and east sides of the river, there were sixteen different forts, and these, together with those on the river and the batteries of the interior line, had in position about three hundred guns.
One ironclad, the Louisiana, mounting sixteen guns of heavy caliber, though she was not quite completed, was sent down to coöperate with the forts. Her defective steam-power and imperfect steering apparatus prevented her from rendering active coöperation. The steamship Mississippi, then under construction at New Orleans, was in such an unfinished condition as to be wholly unavailable when the enemy arrived. In the opinion of naval officers she would have been, if completed, the most powerful ironclad then in the world, and could have driven the enemy's fleet out of the river and raised the blockade at Mobile. There were also several small river-steamers which were lightly armed, and their bows were protected so that they could act as rams and otherwise aid in the defense of the river; but, from the reports received, they seem, with a few honorable exceptions, to have rendered little valuable service.