In the middle of October 1863, Major-General Quincy Gillmore and Rear-Admiral John Dahlgren weighed the next moves for their joint forces with respect to their assigned goal of Charleston, South Carolina. The assessments, proposed plans, and evaluations offer insights on points technical, tactical, strategic, and political. There was also much subtle finger pointing between the two chiefs. At the same time Dahlgren exchanged messages with Gillmore on October 17-18, he also provided an assessment of the situation to the Secretary of the Navy. The lengthy message included a report of the ironclad repairs, assessment of the Confederate defenses, proposed courses of action, assessment of relations with the Army, and a request for official sanction of direct actions at Charleston. For now let me focus on Dahlgren’s evaluation of the Confederate defenses. Those came under a section titled “Impediments in the harbor.”
1st. As regards these, some are plain enough, such as the continuous line of works extending from [Fort] Moultrie on the right, Fort Johnson and its dependencies on the left, Fort Ripley, a small work farther on to the right, supported by the three ironclads, and farther on to the right Castle Pinckney. The first two are formidable works, having been extended and strengthened by the labor of large numbers of men for some time, the rest only so as a part of a system.
2d. There is also a line of piles in front of Ripley that has its purpose, but which is now ascertained not to extend across the channel. The impediments not visible, and of which nothing certain is known, are these which are submerged.
3d. First come those of rope between Sumter and Moultrie. All prisoners, deserters, and other persons of the enemy whom I have seen concur in the existence of these, though having only a partial knowledge of them; they differ in describing their mode of arrangement. My own scouts have been among them and agree they are there, and some of my boats have gone well past them. Various devices have been prepared to get rid of them, and it is not probably that we shall be much troubled in passing them.
4th. But there is another kind of impediment of which we know nothing with certainty – the torpedoes. They may exist or they may not, may act or not when resorted to, and may be anywhere. No one can give certain information in respect to them; some have seen such devices while being made; some think they are located in one place, and some in another, and there is, on the whole, the greatest uncertainty in regard to them. I have examined a number of deserters and prisoners, among them veterans accustomed to the harbor, and one pilot; they all concur as to their ignorance of these torpedoes.
Clearly the biggest fear Dahlgren counseled was that of the torpedoes. During over two months of continuous exposure to the guns of Sullivan’s Island, the ironclads had survived even the most focused efforts. The obstructions were rated minor nuisances. It was those damned torpedoes he feared. By this time in the war monitors such as the USS Montauk had suffered damage from those devices. The USS Cairo was somewhere up the Yazoo River at the bottom. So he had reason to worry.
(Another aspect to this… consider it the “true up” that we might apply safely from the perspective of 150 years … is the actual Confederate dispositions. Allow me to follow that up with a look at the defense of Charleston after the fall of Morris Island in a later post.)
Dahlgren continued adding:
All of these, however, will not prevent a suitable force from entering and penetrating to Charleston. There will be seven monitors ready for this service when the repairs are completed, and if no greater consequences depended on the issue than defeat and the loss of some of these I should not hesitate to enter as soon as the monitors were in condition for service. But the defeat might be so serious as to involve the communications of our forces on the islands, the blockade, and other material advantages, and I confess I am not prepared to risk these unless relieved of the responsibility of such a result, in which case nothing would be more acceptable to me than the enterprise.
This is the point at which we must recall only a year earlier Dahlgren boldly offered to command an attack directly against some of the same defenses (and at a time that Fort Sumter was far more a threat than in the fall of 1863). A year later, in the chair to command a similar action, Dahlgren wanted official sanction.
The assessment of the Confederate defenses highlighted technical-tactical concerns. These were, if I may, in Dahlgren’s wheelhouse. Much as Gillmore fell back on his technical expertize with siege warfare, one might expect Dahlgren, with his years of experience and technical innovation, to respond with a strong suite of solutions to mitigate any risk. Yet, here Dahlgren offered little more than another ironclad attack.
Again, consider the question. Was Fort Sumter and the inner Charleston harbor beyond attainable objectives in the fall of 1863? Dahlgren thought so, but only with risk. That risk might be measured as a potential sunken ironclad… or two… or three. But make no mistake, the measure would weigh on the political scales.
(Citations from ORN, Series I, Volume 15, pages 52-3.)