Batteries in the Marshes: The Defenses of Savannah, Part 2

Continuing from yesterday’s post, I’ll first turn to the improvements to the fortifications directed by General P.G.T. Beauregard in October 1862.

Although after his initial, but brief September 1862 inspection, Beauregard considered the defenses well placed, after the detailed inspection in October, he found many issues with gun placement in the works.  Beauregard called for repositioning of guns in almost all the existing major fortifications.  In addition he cited poor magazine and traverse placement in several of the batteries.

Those “tuning” chores in order, Beauregard ordered several new batteries erected.  To produce a cross-fire against any threat from Whitemarsh Island, he ordered a three-gun battery built at Greenwich Point on St. Augustine Creek. Turning again to the map, that battery is depicted in green and those from the earlier date in yellow (and remember the base map depicts fortifications as they existed in December 1864, so don’t jump ahead with this story and ignore the red and blue markings!)

Notice how the guns from Carston’s Bluff, Greenwich Point, and Thunderbolt sealed off any approach from Whitemarsh Island.

Further south, Beauregard wanted a battery on Rosedew Island to cover the Little Ogeechee River. And to further protect the causeway leading south to this extended line, he directed the formation of a siege train and additional works on Isle of Hope. The later, along with another three-gun battery, would help cover the approaches from Skidaway Island.

Rosedew Island is just left of center, again in green.  The Isle of Hope fortifications extended at different points from the center-right, upwards.  I’ve depicted two locations on opposite ends of the island.  However I am not sure exactly where the three gun battery, named Lake Bluff Battery, was located (UPDATE:  Don’t know why I overlooked this name.  Lake Bluff Battery – as noted in the table below, was located on the Altamaha River well southwest of Savannah.  The battery was an isolated and remote defense, but is of interest to those who like the obscure stories!  Look for a follow up post.).

Beauregard also directed a series of signal stations – Genesis Point, Rosedew Island, Beaulieu, Isle of Hope Causeway, Thunderbolt, Carston’s Bluff, Fort Jackson, Fort Boggs, and in Savannah.

But with regard to the guns in the forts, Savannah continued to make do with what was available after the harder pressed sectors received their allocations.  I’ve not located any returns for January or February 1863, but Major General Benjamin Huger provided a well detailed inspection report dated March 31, 1863. I derive the table below from that report.

Not listed here are several field guns, including rifled guns, listed in the fortifications.  The value of these guns was protecting land-side approaches to the forts, not defending the waterways.  The siege train employed for the Isle of Hope consisted, in March 1863, of four 8-inch siege howitzers, two 4-inch Blakely rifles, and one 20-pdr Parrott.  Also not listed above were a couple of Confederate ironclads – the CSS Georgia (although just a floating battery) and the CSS Atlanta – to supplement the land defenses.

Huger also provided a sketch indicating the facings of the guns along the Savannah River.

Clearly the Confederates had the Savannah River tied up nicely.  Further south, the works along the Ogeechee, Little Ogeechee, and Vernon Rivers required more attention.  If Savannah were to remain an option for blockade runners or commerce raiders, the Confederates had to control those waterways.

Looking at events 150 years ago, it was the battery at Genesis Point, by this time called Fort McAllister, which was receiving the attention of the Federals.  As noted above, the fort was armed with one 10-inch columbiad, one 8-inch columbiad, one 42-pdr gun, three 32-pdr guns, one 32-pdr rifle, and one 10-inch mortar.

Reproduction Columbiad at Fort McAllister

Those seven guns (and one mortar) would soon duel with Federal ironclads.

Reproduction 32-pdr Gun at Fort McAllister

(The referenced reports and orders appear in OR, Series I, Volume 14, Serial 20, pages 657-60 and 853-8)

Batteries in the Marshes: The defenses of Savannah, Part 1

Now if you consider the Charleston area a backwater by the middle of the Civil War, then maybe Savannah, Georgia qualifies as an eddy. But just as Charleston saw considerable activity in January 1863, the combatants in the Savannah sector were restless. Yesterday “Seaman Rob” provided a look at the ironclads bombardment of Fort McAllister, an operation taking place 150 years ago this week. Allow me to address the “land” side of activity in that theater.

After the fall of Fort Pulaski, activity around Savannah tapered off. Mostly garrison routine with a few patrols and blockade activity. The inactivity was partly due to limited forces arrayed. Any serious move against Savannah required more Federal troops, perhaps three times the number committed. And on the other side, the Confederates barely had enough troops to maintain the works.

However that is not to say Savannah lacked importance. The port remained an option for blockade runners. Even though Fort Pulaski denied access to the Savannah River, other routes allowed secretive blockade runners to slip in and out. The map below highlights the location of Wassaw and Ossabaw Sounds, with Savannah in the upper center (and Fort Pulaski on the upper right).

The map above is from the Official Records Atlas. It is a color version of a map drawn up at the war’s end and depicts fortifications in place at the time Major General William T. Sherman captured Savannah in December 1864. So keep that in mind when looking at the installations indicated in red and blue.

It was possible for ocean-going ships to work down from the port of Savannah, through St. Augustine Creeek and the Wilmington River, to reach Wassaw Sound. Lighter draft vessels could work the waters inshore of Sidaway Island to reach Ossabaw Sound. Furthermore, blockade runners could take shelter in the Ogeechee River (meandering across the lower left of the map) behind a well placed Confederate battery. (And I would add that all of the waterways named here are part of the modern Intercoastal Waterway.)

Notice also the proximity of the Atlantic and Gulf Railroad which, through several junctions, connected Savannah to Macon and Florida. Like many railways in the Confederacy, this became an important supply line. Reports during the war indicated vessels drawing up to 13 feet of draft could reach the railroad where it passed over the Ogeechee River, if well piloted.

Ogeechee River, just upstream from the Railroad Crossing

But not only were those waterways havens for blockade runners, they also offered up avenues for Federal raiders. The problem facing the Confederates was, with limited forces, the need to cover a vast area filled with tidal marshes. In September 1862, the Military District of Georgia counted only 8,371 present for duty.

Conversely, the problem for the Federals was how to move past those marshes and get to firm ground for maneuver. The Federal Navy couldn’t move up the rivers without ground support. And there simply was no “ground” from which to support! And like the Confederates, the Federals lacked the force to do much campaigning. An October 1862 return tallied only 12,837 present for duty throughout the entire Department of the South (covering South Carolina, Georgia, and north Florida).

Shortly after taking command of the Department of South Carolina and Georgia at the end of August 1862, General P.G.T. Beauregard began an inspection tour. He visited Savannah on September 21, 1862, but time constraints prevented a detailed review. He returned a month later in October for a very thorough inspection of Savannah’s defenses. This section of the map depicts the defenses immediately east of Savannah, extending south from the Savannah River. The fortifications indicated in Beauregard’s October report are depicted with yellow boxes (again, keep in mind that the base map depicted the works existing in December 1864).

The Savannah River defenses centered on a line roughly three miles downstream from Savannah. Beauregard considered Fort James Jackson, dating to the War of 1812, “a very weak work.” Battery Lee, just downstream, was better sited and armed. A battery across the marsh on Carston’s Bluff protected the back of Fort Lee. Across the river from Fort Jackson was a “Naval Battery” on a low island in the river (later named Fort Tattnall). Battery Lawton on Barnwell Island completed the line. Fort Boggs, just outside Savannah, provided another layer of river defense. Batteries near the waterfront and on Hutchinson Island provided close defense of the river-port.

To the south, the lone work defending the Wilmington River was Thunderbolt Battery. Very little covered St. Augustine Creek, which connected the Wilmington and Savannah Rivers. And St. Augustine Creek also lead back east to the waters behind Tybee Island, in close proximity to Fort Pulaski. However, while this offered a path for Federal advances, there was precious little ground for the Federals to stage for an attack across St. Augustine Creek towards Savannah. The Federals had patrolled Whitemarsh Island, the most suitable for Federal needs. But even there the marshes prohibited any direct move across to Savannah.

Further to the south of Savannah, very little covered the waterways and tidal marshes. Beauregard reported only two works – a battery at Beaulieu and a another battery at Genesis Point (later named Fort McAllister).

Here again, marshes kept the Federals at arms length. Skidaway Island might serve as a base for attacks inland – but only if a commander found a way through the tidal flats and marshes.

Ogeechee River at Fort McAllister

Beauregard included an inventory of the guns located in the forts defending Savannah from seaward approaches. (Beauregard also detailed the western, or land, defenses of the city, where 37 siege guns, howitzers and carronades were present.)

As with Charleston, the majority of ordnance on hand was older, obsolete 32-pdr guns. But Savannah had only five rifled guns. Recall that Fort Pulaski had forty-six guns at the time it fell, including five 10-inch columbiads, nine 8-inch columbiads, three 42-pdr guns, twenty 32-pdr guns, and two 4.5-inch Blakely rifles. Certainly iron Beaureagard wished he had back in the winter of 1863.

Beauregard was not just concerned about the number of guns defending Savannah. He also no less than 29 actions – ranging from improved magazine placement to plans for removal of women and children at Federal approach – required to better defend the city. I will look at some of those actions taken through January 1863 in the next post.

(Beauregard’s reports are found in OR, Series I, Volume 14, Serial 20, pages 633-4, 645-648, and 657-60.)

Closing note on “stone mortars”: Mortars and “scatter” projectiles

Earlier I wrote about the stone mortars and their somewhat limited operational niche.  The main purpose of these cannons was to break up enemy troop concentrations that stood behind protective fortifications.  Such situations occurred when a besieger had breached a fortified wall.  The besieger would then have troops massed to exploit the breach.  Likewise the defender would mass troops to seal the breach.  The tactical requirement, in such situations, was a weapon to drop projectiles on top of the enemy – vertical fires instead of the horizontal trajectories seen with guns.

All very well if you are breaching a Vauban fort every other day of the week.  But such occurred exactly zero times in the American Civil War.  But such did not mean a similar, if not essentially the same, requirement was absent.  Indeed, by 1864 as battle lines in Virginia and Northern Georgia took shape, massed infantry formations under the protection of trench lines -preparing for attacks or counter-attacks – became common targets.  In that tactical world, vertical trajectories became an increasingly desirable practice for artillery fire.

Conventional shells fired from mortars could provide just such vertical trajectories.  And as students of the Overland Campaign will point out, the Ceohorn made its appearance there.  But considering the rudimentary fuse technology of the time (recall the cutting of paper fuses to time of flight estimates), standard shell fire from mortars were short of perfect.  There was no direct solution during the Civil War.  Decades later fuse technology advanced to resolve this.  But for the Civil War, the “sure” anti-personnel projectile was still a “scatter” type.

I would point out the use of “scatter” projectiles from conventional mortars was known well before the Civil War.  Muller wrote of such tests in his Treatise of Artillery.  In his 1861 Artillerist’s Manual, John Gibbon noted that defenders should load Coehorn mortars with grape-shot to form the last ditch defensive lines in fortifications.  But I would point out that Gibbon envisioned their use against an enemy reaching the parapet of the fortification, not against an enemy behind cover.  Still the suggested implementation alludes back to the intended use of the stone mortars by defenders in the Vauban context.

The Federals experimented mortar case-shot projectiles late in the war.  Case shot for both 10- and 13-inch mortars were issued in limited numbers.  A 10-inch case shot was filled with twenty-seven iron balls, the same used in 12-pdr cannister rounds, and provided with a 2.5 pound bursting charge.  The 10-inch versions were used with good effect during the Battle of the Crater, and are credited with silencing Confederate artillery for a short period of that engagement.  However gunners complained about premature explosions experienced with the mortar case-shot.

As mentioned above, ultimately this tactical requirement was solved by the use of case-shot, under the name “shrapnel”, with more advanced fuses that ensured air bursting and a shell design that ensured the sub-projectiles exited on a more predictable course. I cannot resist using this animated gif to illustrate the World War I-era projectile system:

I’d go into the success and ultimate failure of that projectile type, but this is a Civil War blog.  I’ll have to save that for another venue…. right XBrad?