By the middle of December, Major-General Quincy Gillmore’s plans to take Charleston, South Carolina had hit a dead end. The Tenth Corps, Department of the South, had taken full possession of Morris Island and used it as an artillery platform to wreck Fort Sumter and smite Charleston itself. But any further progress depended upon naval action. And for several reasons Rear-Admiral John Dahlgren was not in position to trigger that action. (And I’ll examine those reasons a just airing in the near future.) Gillmore had 33,000 troops present in the department, of which all but around 6,200 were outside Charleston. That number of troops could not lay idle for long before Army command in Washington decided to reinforce other theaters. So Gillmore laid out some options in a letter on December 15, 1863.
Gillmore began with a review of options for advances on Charleston. The status quo was to wait for Dahlgren to push the ironclads into the harbor. But Gillmore considered at least two lines of operations:
I feel myself tied to the original programme, however, although the conditions of the problem have undergone material modifications since the outer line of defenses was broken by the reduction of the works on Morris Island and the demolition of Fort Sumter. In order to co-operate with the fleet now, with a promise of success, I must work on James Island from the Stono, or on the mainland from Bull’s Bay, directly in the teeth of the enemy’s means of concentrating forces by railroad. No such operations were originally contemplated. Positions on the shore of the inner harbor that I could once have seized and held, after the iron-clads got secure possession of the inner waters, now bristle with guns, and I must approach them by land, by a siege of the outer line of land defenses.
In a separate letter sent two days later, Gillmore elaborated on his preference between these two lines of advance. Bull’s Bay was out. It offered poor landing sites. And as the map below demonstrates (blue arrow on the right), there was a lot of ground to cover before reaching anything vital.
On the other hand, an advance on James Island (blue arrow on the left) would allow the garrison from Folly Island to support. The Stono River offered good landing sites. Furthermore, Federals held positions on the southern end of James Island which would serve as launch points. But Gillmore felt any such operation needed 10,000 to 12,000 reinforcements. And not mentioned in Gillmore’s letter, but offered in earlier correspondence, an advance across James Island exposed the left flank to attack. Recall too that Dahlgren had also dismissed similar lines of advance in October.
But, as one is apt to do in a course of action assessment, those two offered lines of advance were the “bad” options to contrast with other, more palatable, options. The other two offered were actions against Savannah and into Florida:
(1) The capture of Savannah by surprising the enemy’s batteries on Saint Augustine Creek. The admiral will co-operate with me without instructions. I will not go into details. I would propose to take command in person. Should the surprise fail, I would not push the attack against a concentrating enemy, and no serious loss need be feared. I would then take a portion of the force prepared against Savannah, and with it (2) operate in Florida and recover all the most valuable portion of that State, cut off a rich source of the enemy’s supplies, and increase the number of my colored troops, I will not go into detail.
In almost the same breath, Gillmore began to downplay any chance of success against Savannah. He cited reports that Fort Jackson, on the Savannah River, was strengthened against land attack. And let me dust off one of my maps of the Savannah defenses:
St. Augustine Creek runs between Whitemarsh Island and the mainland (on the left). By December 1863, the Confederates had strengthened that line. And they were maintaining an active picket line across Whitemarsh Island. Gillmore probably knew this line of advance offered no quick turns. A “maybe” option to be entertained.
But the Florida expedition? Gillmore sent Colonel Milton Littlefield, of the then forming 4th South Carolina Volunteers (Colored), to Washington with information about that proposed action. Gillmore had all but given up on any ideas of taking Charleston by spring, particularly if the navy didn’t break into the harbor and no reinforcements were forthcomming. In Florida, however, he saw opportunity.
(Citations from OR, Series I, Volume 28, Part II, Serial 47, pages 129-30.)