The three breaching batteries-Sigel, Scott, and McClellan-were established at a mean distance of 1,700 yards from the scarp walls of Fort Pulaski. 

The circumstance, altogether new in the annals of sieges, that a practicable breach, which compelled the surrender of the work, was made at that distance in a wall 7½ feet thick, standing obliquely to the line of fire and backed by heavy casemate piers and arches, cannot be ignored by a simple reference to the time- honored military maxims that "Forts cannot sustain a vigorous land attack," and that "All masonry should be covered from land batteries."... 

At Fort Pulaski an excellent opportunity was afforded on the scarp wall near the breach for obtaining the actual penetration of the several kinds of projectiles. An average of three or more shots for each caliber was taken, giving the following results, which may be relied upon as correct [see replicated table below]: 
 

The...table indicates very prominently, although it affords no exact means of measuring, the great superiority of rifle over smooth-bore guns for purposes requiring great penetrating power.... 

With heavy James or Parrott guns the practicality of breaching the best-constructed brick scarp at 2,300 to 2,500 yards with satisfactory rapidity admits of very little doubt. Had we possessed our present knowledge of their power previous to the bombardment of Fort Pulaski, the eight weeks of laborious preparation for its reduction could have been curtailed to one week, as heavy mortars and columbiads would have been omitted from the armament of the batteries as unsuitable for breaching at long ranges. 

It is also true beyond question that the minimum distance, say from 900 to 1,000 yards, at which land batteries have heretofore been considered practically harmless against exposed masonry, must be at least trebled, now the rifled guns have to be provided against. 

The inaccuracy of the fire of the 13-inch mortars has already been adverted to. Not one- tenth of the shells dropped inside of the fort. A few struck the terre-plein over the casemate arches, but, so far as could be observed by subsequent inspection from below, without producing any effect upon the masonry. Whether they penetrated the earth work to the roofing of the arches was not ascertained. 

Two or three striking in rapid succession into the same spot over an arch might be expected to injure it seriously, if not fatally. Such an occurrence would, however, be rare indeed. Against all, except very extraordinary casualties, it would be easy for a garrison to provide as they occurred, by repairing with sand bags or loose earth the holes formed in the terre-plein by shells. 

We may therefore assume that mortars are unreliable for the reduction of a good casemated work of small area, like most of our sea-coast fortifications. 

As auxiliary in silencing a barbette fire, or in the reduction of a work containing wooden buildings and other exposed combustible material, mortars may undoubtedly be made to play an important part. 

For the reduction of fortified towns or cities, or extensive fortresses containing large garrisons, there is perhaps no better arm than the mortar, unless it be the rifled gun, firing at high elevations. 

To the splinter-proof shelters constructed for the seven advanced batteries [this implies one was likely present in the vicinity of Battery Halleck as well] I attribute our almost entire exemption from loss of life. We had 1 man killed by a shell from one of the mortar batteries outside the fort, which was the only casualty.... 

Very respectfully, your obedient servant, 

[Excerpts from] Report of Lieutenant Horace Porter, Ordnance Department 

Fort Pulaski, Ga., April 12, 1862. 

To: W. L. M. Burger 

1st Lieut. Vol. Eng. A. A. Adj.-Gen. 

Sir:-In compliance with directions from General Gillmore, I have the honor to submit the following report concerning the ordnance and ordnance stores used in the investment and bombardment of Fort Pulaski... 

18. Being ordered to Port Royal to collect ordnance for Tybee Island, I returned to that post February 22d, and started for Tybee Island February 24th. 

19. The following ordnance and ordnance stores were landed at different times, and placed in position in the batteries opposite Fort Pulaski:
 

12 4 6 4 2 2 1 5

13-inch mortars and beds 10-inch siege mortars and beds 10-inch columbiads and carriages 8-inch columbiads and carriages 84-pounder James rifles, " (old 42-pounders rifled.) 64-pounder James rifles, " (old 32-pounders rifled.) 48-pounder James rifles, " (old 24-pounders rifled.) 30-pounder Parrott rifles, "

Implements and equipments, and nearly 900 rounds of ammunition for each piece.

3,000 barrels of powder

20. The heavy guns were landed by lowering them from the vessels into lighters, having a strong decking built across their gunwales. They were towed ashore by rowboats at high tide, often in heavy surf, and careened by means of a rope from shore, manned by soldiers, until the piece rolled off. At low tide this was dragged above high-water mark. 

21. For the purpose of transporting the 13-inch mortars, weighing 17,000 pounds, a pair of skids was constructed of timber, ten inches square, and twenty feet long, held together by three cross-pieces, notched on. One end of the skids was lashed close under the axle of a large sling-cart, with the other end resting on the ground. The mortar was rolled up by means of ropes until it reached the middle of the skids, and checked. Another large sling-cart was run over the other end of the skids, which was raised by the screw, forming a temporary four- wheeled wagon. Two hundred and fifty men were required to move it over the difficult roads by which the batteries were reached. 

22. I can pay no greater tribute to the patriotism of the 7th Connecticut Volunteers, the troops generally furnished me for this duty, than to say, that when the sling-carts frequently sank to their hubs in the marshes, and had to be extricated by unloading the mortar, rolling it upon planks, until harder ground could be found, and then reloading it, they toiled night after night, often in a drenching rain, under the guns of the fort, speaking only in whispers, and directed entirely by the sound of a whistle, without uttering a murmur.... 

25. The 13-inch guns were mounted by means of the ordinary garrison gin, by increasing the number of blocks, giving four sheaves above and three below. It was found that when the truck-wheels of the iron beds for the 13-inch mortars were thrown into gear they sank into the deck planks of the plat- forms, and did not relieve the cheeks of sufficient weight to enable the pieces to be moved to and from the battery. Two pieces of flat iron, five feet long, four inches wide, and half an inch thick, were, at the suggestion of General Gillmore, let into the platforms under the wheels, projecting an eighth of an inch above the surface, the inner edges two inches outside of the rails. The wheels then worked to perfection.... [This reference indicates that appreciable quantities of flat iron were used in the transport of equipment; these might be a source for the metal found in the floor of the antechamber in 1990.] 

28. The 13-inch mortar cartridge bags not having arrived, the powder was poured into the piece loose, and adjusted in the chamber by the gunner. This method was attended by very little more inconvenience than is experienced in smaller mortars.... 

42. During both days of the bombardment the wind, which blew from right to left, was extremely unfavorable for mortar firing. This in connection with the fact that the gunners had never before fired a piece, and had been drilled only ten days, accounts in some degree for the loss of so many shells from the mortars. 

43. The nearest 13-inch mortar [Battery Halleck], firing at an elevation of forty-five degrees, was 2,650 yards, and the farthest 3,400 yards; too great a distance for a successful vertical fire against a small area like that of the fort.... 

53. The 13-inch mortars were fired once in ten or fifteen minutes. One was fired three times in fifteen minutes, without any extraordinary exertion on the part of the cannoniers.... [This may have been one of the mortars at Battery Halleck, since that is where Porter was stationed at the start of the engagement.]