There was a double line of cribs extending entirely across; each of these was made of heavy timbers; eighteen-inch to twenty-inch, stoutly framed together, with platforms at each tier, on which were placed piles of brick. Their tops were about level with high-water, and in the different parts of the South Branch, must have had a height of thirty to thirty-five feet from the bottom.
The party from the navy, consisting of a corps of divers and a steam-tug, were occupied two or three weeks in removing two or three of these, which opened a passage of not more than one hundred to one hundred and twenty-five feet. In the North Branch, the divers who contracted, effected a similar opening in less time, as the water was little more than half the depth of the South Branch.
First. The first battery from above that commanded these obstructions was Fort Lee, a strong earthwork, at one thousand five hundred yards; it had ten guns, of which two were ten-inch, and three were eight-inch columbiads.
Second. Fort Jackson, at two thousand yards, has five guns, of which two are eight-inch columbiads.
Third. Battery Lawton, at two thousand yards, five cannon, of which two were ten-inch columbiads; one was an eight-inch columbiad.
Fourth. Water-battery, at two thousand yards, six guns, of which two were ten-inch columbiads, and one an eight-inch columbiad.
About one thousand five hundred yards above these obstructions was another row of similar crib-work, extending from Fort Lee to Battery Lawton, on island directly across the channel — the channel being under the fire of these works, at ranges varying from two hundred to six hundred yards.
Piles were also driven and obstructions sunken at different parts of the channel, where it presented any intricacy. So long therefore as the rebels held these batteries, they covered these obstructions by the fire of twenty-six cannon, of which thirteen were columbiads.
As the Savannah River is lined with marshes to the line of obstructions, no troops could operate on either side, and the vessels that approached could have no cooperation, while they were also under the fire of the battery of fourteen guns on Whitmarsh Island, at a range of----yards.
Savannah could, however, be approached by landing troops in St. Augustine Creek, whence roads led directly to the city — the distance not exceeding three miles--which was also easy riflerange, and permitted the destruction of the city.
The navigation from the sea is better by this route than by Savannah River.
To guard against this danger, there were several batteries:
First. Turner's Rocks, six guns, four of them ten-inch columbiads, and one eight-inch columbiad.
Second. Thunderbolt, twelve guns, of which one was a ten-inch columbiad, and four were eight-inch columbiads.
Third. Bartow, with its outpost, Causton's Bluff, sixteen guns, of which one was a ten-inch columbiad, and three were eight-inch columbiads.
Obstructions of various kinds were sunk in different parts of the narrow channel.
The heavy cannon on this line were six ten-inch columbiads, and eight eight-inch columbiads, looking upon a deep but narrow and crooked channel.
Just in the midst of this net-work of defences lies Whitmarsh Island. Our landing and intrenching here was prevented: first, by the battery of. Turner's Rocks; second, by a battery on its east side of fourteen guns, which, with obstructions, closed the passage by the Little Tybee; third, by an intrenchment, extending diagonally across the island, with small field-works at intervals; fourth, by the guns of Thunderbolt enfilading these intrenchments; fifth, by the guns of Bartow.
The whole of this powerful assemblage of works was open, however, to being taken in reverse, and turned or passed by troops landing on the Vernon and Ogeechee.
To prevent this, the Vernon was closed by obstructions, and commanded by Fort Beaulieu with nine cannon, of which two were ten-inch columbiads, and one was an eight-inch columbiad.
Big Ogeechee was closed by obstructions, and Fort McAllister, having twenty-four guns, of which three were ten-inch columbiads, and one was an eight-inch columbiad.
Little Ogeechee was defended by Rosedew, with six guns, of which three were ten-inch columbiads.
All of these streams were so narrow at the location of these works, that a steamer would turn with difficulty, if at all.
Batteries were also placed on the roads leading to the city from these places. The whole number of cannon in the works enumerated above on the water-courses was one hundred and thirteen, of which twenty were ten-inch columbiads, and nineteen were eight-inch columbiads.
Besides these, there were one hundred and sixteen cannon of less calibre in the land-works immediately around the city, and on the roads leading to it, making a total of two hundred and twenty-nine cannon defending Savannah by land and water.
I think it clear from this, that the city was not reducible in any of these directions, save by the united exertions of a competent land and sea force.
If General Gillmore had forty thousand men, which I heard after he left that he had had, I think the place might have been captured.
