Even with the fall of Battery Wagner on September 7, 1863, the engineers remained busy around Morris Island. New batteries were needed to bombard Fort Sumter and Sullivan’s Island beyond. Existing works and other facilities had to be transformed to better front James Island. And, of great interest to freshly promoted Major-General Quincy Gillmore, a set of batteries to fire on Charleston itself.
Again, keep in mind that Gillmore and other senior Federal officers rationalized Charleston as a legitimate military target. The city docks bristled with fortifications. The wharfs service blockade runners. The city warehouses supplied the Confederate army. Factories and shops provided munitions and equipment. From our 21st century perspective, this was sound logic. Indeed, even within the conventions of 19th century warfare, besieged cities were not immune from bombardments. And with the Federals in possession of Morris Island, the city of Charleston was besieged.
The first effort to bring Charleston under fire resulted in the Marsh Battery, and ended when the Swamp Angel burst. Shortly after that famous gun opened fire, Gillmore directed Colonel Edward Serrell to build another, larger battery on Black Island to support additional guns aimed at Charleston:
On the morning of the 23d of August, orders were received from the commanding general to put three 30-pounder [4.2-inch] Parrott rifled guns on Black Island, and to so build the batteries for them and construct platforms that they could fire over the enemy’s works on James Island directly upon the city of Charleston. The range, as ascertained by the Coast Survey map, was required to be 8,800 yards.
Black Island lay midway between Morris Island and James Island, in the marshes. Confederates intended to construct a battery there in the spring of 1863, but never got all the resources in place.
In late July, Federal engineers surveyed the island and constructed an observation post in one of the tall trees there. In early August, the engineers built a causeway leading to Black Island, which was also used for work parties involved with the Marsh Battery.
Serrell started work immediately. The engineers included a four gun battery, a magazine, a fortified camp, a surgery, and a covered way between the facilities. The general layout of these works appears on Plate VI, Figure 1 from Serrell’s report:
The profile of the surgery is depicted with Figures 2 and 3 in the plate above.
The main feature of this line of works was the four gun positions. These were a set of galleries with traverses between.
Behind the battery was a five sided bombproof magazine. Connecting to the magazine was the covered way which lead to the surgery and the camp.
Two of the gun positions used standard siege carriages. The carriage sat on a ramp slightly inclined to the rear, at about 5º, with a pit for the trail to fall into. The gun thus super-elevated, but the ramp allowed for recoil without greatly straining the carriage.
Figure 4 of Plate VII shows the cross section of the pit from side to side. Notice the planking at the top of the pit.
The other two positions in the battery featured an alternate carriage. Dispensing with the wheels and stock trail, the engineers retained the 5º ramp, but blocked in the back of the pit.
The gun’s breech and cascable could drop into the pit. This allowed even higher elevations. The figure below shows the cross section of the pit. Absent is the planking of the other position profile.
The carriage used a set of transoms on top of the main beams. The top carriage slid on those transoms when the gun fired. The crew then used balks to push the gun back into position. Note the cut out in the top carriage (in Figure 4 below) where the breech band passed through the carriage to allow elevation.
After the engineers started work, orders came replacing one of the 4.2-inch Parrotts with a 6.4-inch (100-pdr) Parrott. As wrought iron carriages for the big Parrotts was in short supply, and would not allow the super-elevation required, the engineers and ordnance officers modified the alternate carriage.
This figure shows the gun’s position relative to the carriage for better effect.
Another alternative design placed an eccentric wheel at the front of the top carriage. This made it easier on the crew pushing the gun back into battery.
Moving the 4.2-inch Parrotts into position was relatively easy… if one can consider moving an 8,000 pound gun and carriage on the marsh easy. The crews floated these guns out to the island on boats, then drug them the last 150 yards across to the battery (in the dead of night, in a rainstorm, according to Serrell).
But the 6.4-inch Parrotts required special handling. For that gun, the engineers built a cylinder to fit over the chase of the gun, and secured it with iron bands. The cylinder matched the diameter of the breech band, so the gun lay on a level line.
The gun was then rolled like a log across the marsh along parallel planks.
When mounted, these three guns (one position remained empty) were able to elevate sufficiently to range all of Charleston. However, the positions were not given any significant traverse arrangements. But coupled with 4.2-inch Parrotts mounted in the old Marsh Battery location, the guns could give Charleston considerable grief.
Work on Black Island continued well into September. While the Federals built up the battery, the Confederates sent harassing fires from James Island. But this amounted to little. In fact, on September 18 when an 8-inch columbiad burst while firing on Black Island, killing one man, the Confederates suffered more than the Federals. So much for Charleston fading back into a quiet backwater of the war!
(Source: OR, Series I, Volume 28, Part I, Serial 46, pages 236-8.)