Masked Batteries on Folly Island: First steps in Gillmore’s offensive

Let me return to the barrier islands outside Charleston. By the first week of July 1863, the front lines remained much as they stood earlier in April.


However, inside those lines, Brigadier-General Quincy Gillmore increased the strength of the Folly Island garrison. By July 6 the force under the command of Brigadier-General Truman Seymour included two brigades. Brigadier-General Israel Vogdes’ brigade seven infantry regiments, one independent battalion, and a cavalry detachment, along with most of the artillery on Folly island. Brigadier-General George C. Strong’s brigade consisted of six infantry regiments and an artillery battery. The artillery was later placed under the control of Lieutenant-Colonel Richard H. Jackson, Gillmore’s Inspector-General for greater effect.

The addition of Strong’s troops in early July marked the first steps in Gillmore’s planned offensive against Charleston. As his predecessors and naval counterparts, Gillmore recognized Fort Sumter was the key to the harbor. Much as his adversary, General P.G.T. Beauregard, predicted earlier in the year, Gillmore sought to employ heavy guns to reduce Fort Sumter from Morris Island, just as successfully done against Fort Pulaski over a year earlier.

However, to reach Cumming’s Point at the north end of Morris Island, Gillmore had to strike before Beauregard completed fortification of the south end of the island. Gillmore proposed a surprise shore-to-shore amphibious assault, followed by a rapid advance up the beach to seize Battery Wagner. With the Navy covering the right flank of this advance, the plan looked very favorable on paper. If successful, Gillmore could place heavy Parrott rifles on Cumming’s Point to batter Fort Sumter into submission. Then the Navy might make another go at the harbor entrance… or at least lay within the bar with some immunity to tighten the blockade.

Preparations for the assault on Morris Island actually preceded Gillmore’s assignment to command. Much on his own initiative, Vogdes built defensive works starting after his landing concurrent with the failed ironclad attack in April. He described the island as “covered with a dense and impenetrable forest and tangled underwood, without roads of any description, and impassable except by the east and west beaches, at low tides.” He supervised the clearing of roads along the ten mile island’s interior to support several batteries.

Interior of Folly Island – August 1863

When Gillmore assumed command in mid-June, he instructed Vogdes to continue this activity and specifically construct concealed batteries on the north end of Folly Island overlooking Light House Inlet. As Vogdes later reported, this was no easy task:

A two-fold problem had to be solved; first, to construct formidable batteries within 800 to 1,200 yards of the enemy; second, to conceal them entirely from his notice. This last was exceedingly difficult, as he, the enemy, had a lookout near Secessionville, which overlooked the position, besides having a direct view from Morris Island. However, there being a dense copse wood near the north end, we were afforded the means of solving the second part of the problem.

The grounding of the blockade runner Ruby provided a fortuitous cover for some of Vogdes operations. Confederate observers knew Vogdes’ men were doing work on the north end of the island. But by withdrawing batteries advanced to shell the Ruby, Vogdes gave the appearance Confederate gunners had driven off the Federals. Yet he kept some 1,000 men working day and night on the required batteries. “At least 2,000 rounds were fired by the enemy without our replying, or in the least regarding it. I regret to state that several men lost their lives, and several were wounded.”

Lighthouse Inlet1

By July 3, Vogdes’ completed ten battery sized positions overlooking the inlet. This included splinter-proofs and magazines with 200 rounds of ammunition for each weapon.

On July 9, Lieutenant-Colonel Richard H. Jackson assumed command of the batteries. On the maps submitted with Gillmore’s report, those arrangements appeared as such:


Jackson described the arrangements as two lines (though I’d call it three). The first line consisted of:

  • A – Two 3-inch rifles, a section from Captain Charles Brayton’s company, 3rd Rhode Island Artillery.
  • B – Four 20-pdr Parrott rifles, Captain Charles Strahan’s company, 3rd Rhode Island.
  • C – Four 30-pdr Parrott rifles, Battery C, 1st U.S. Artillery, under Sergeant Michael Leahy.
  • D – Six 10-inch mortars, Captain Albert Green’s company, 3rd Rhode Island.
  • E – Two 3-inch rifles, a section from Captain Charles Brayton’s company, 3rd Rhode Island.
  • F – Six 10-pdr Parrott rifles, Battery E, 3rd U.S. Artillery, under Lieutenant John R. Myrick.
  • G – Eight 30-pdr Parrott rifles, Captain Richard Shaw’s company, 3rd Rhode Island.
  • H – Four 10-inch mortars, Captain Joseph Comstock’s company, 3rd Rhode Island.

The second line contained two positions:

  • I – Six Wiard 3.67-inch rifles, Battery F, 3rd New York Light Artillery, commanded by Lieutenant Paul Birchmeyer.
  • J – Five 8-inch mortars, Captain Henry Holbrook’s company, 3rd Rhode Island.

All told the batteries focused thirty-two rifled pieces and fifteen mortars on the south end of Morris Island.

Next I’ll look at the opposite side of Light House Inlet and the Confederate batteries.

(Citations from OR, Series I, Volume 28, Part I, Serial 46, page 351. Details of the artillery arrangements are listed in a report by Lieutenant-Colonel Richard H. Jackson on page 349.)

Published by Craig Swain

"Historical marker hunter" and Civil War enthusiast.

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