Fort Clinch, overlooking Cumberland Sound in northern Florida, was among the last Third System fortifications started in the United States. Work on the fort began in 1847.
At the outbreak of war, the fort remained incomplete and lacking armament. Little was done while the Confederates held the fort early in the war. In early 1862, Federals reoccupied the fort. During the war, Federal garrisons worked to complete the fort. But being a remote, minor post in the Department of the South, the work was not finished by the summer of 1864.
In some minds – particularly Major-General John Foster in command of the department – there was a need to halt work and reassess the fort’s design in light of wartime experiences. On September 3, 1864, Foster wrote to Brigadier-General Richard Delafield, Chief of Engineers, in Washington, to relate the defects of Fort Clinch that needed attention:
General: I have the honor to acknowledge the receipt of your indorsement of the 19th of August, l864, upon my letter of the 19th ultimo, desiring me to give the particular defects to which I objected in the plan, &c., of Fort Clinch. In compliance therewith I submit the following as the most important, &c.:
First. Fort Clinch is not, in my opinion, located so as to command properly both the anchorage and the entrance channel. This will necessitate the erection of outer batteries to command the channel near the location of the rebel batteries and also of inner batteries to command the harbor.
Second. The proximity of a range of sand hills to the fort will afford cover to an enemy’s advance to erect batteries against the fort or to assault the fort after a breach has been effected.
Third. The masonry bastionettes can easily be demolished by the rifled guns in use in the army and the flanking arrangements for the ditch be thus destroyed.
Fourth. The chemin de ronde can also be easily knocked down with rifled guns, and the ascent of the scarp thus be rendered tolerably easy to an assaulting column.
Fifth. The counter sloping glacis will afford greater facilities to an enemy’s assaulting column than to the garrison.
The above constitute the main defects, to which I thought it my duty to call the attention of the department.
Just the “main defects” mind you. And we are left to assume Foster had more in mind. Foster’s resume, by this time of the war, lends a lot of weight to his opinion. Before the war, he’d worked on Fort Sumter. He was in Fort Sumter when the Confederates bombarded it. And as of that summer, he was in the process of “dismantling” the fort by long range artillery. So Foster knew a thing or two about coastal fortifications and their weaknesses.
The first two defects cited by Foster are easily seen looking at a map of Cumberland Sound. In this case, let me use an 1869 chart of the sound:
As Foster pointed out, twists and turns of the channels left many areas up the Cumberland Sound and behind near Old Fernandina out of reach for the fort’s guns. It was not so much a factor of range, but a problem of the terrain masking view. In the age of sail, this was probably not a major issue. But in the age of steam powered ironclads, the position of the fort would leave an adversary the option to simply “run past the batteries.”
Likewise, all that “rough” area between the fort and Fernandina, which was those sand hills mentioned by Foster, would allow an adversary an approach. Something the Federals knew well how to do from experience at places such as Fort Pulaski, Fort Gaines, and Morris Island. Sand hills… as seen at many points along the American coastline… like on Amelia Island, where Fort Clinch stood.
Which ran right up to the back of the fort. If the garrison didn’t cut down the scrub brush and trees that grew on those sand hills, the fort would have practically no line of site from its most vulnerable point.
In fact, the trees would grow taller than the fort, if not trimmed back!
With respect to Foster’s third point, consider this view:
Looking across a land-facing walls of the fort, one of the bastionettes is in the right foreground and another in the distant center. Foster suggested these were easily flanked by siege batteries. And as demonstrated at Forts Pulaski and Sumter, that nice brick-work could not stand against rifled artillery.
And what is that “chemin de ronde” mentioned in point four? That would be the walkway behind the battlements of the fort. Today this is the walkway behind the walls:
As it is between an interior berm and the wall, and there is no proper chemin de ronde here, my supposition is that someone listened to Foster at some point, and the interior arrangements were modified.
The fifth and last point questions the placement of the fort’s exterior glacis, designed to resist or deflect shots at the fort, and thus protect those brick walls. Today that glacis is not really a glacis. But there is somewhat a counter-slope behind the rise of the glacis, which alludes to Foster’s point:
The rise on the right side of this view afforded the attacker more protection than the defender. Perhaps better seen in this perspective:
Technically, Foster’s objections were not intended to oppose further work on the fort. Rather to request refinement of the design. In the light of Civil War experience, there had to be questions about further expenditures on masonry forts of this type.
But this was a pre-war project, with roots well established. Fort Clinch would be completed as intended, because the bureaucracy was there to ensure completion.
Benefiting from wartime work, Fort Clinch was completed in the late 1860s. But it was placed in caretaker status. Worth noting, the only time the Army actually garrisoned a “completed” Fort Clinch was during the Spanish-American War.
(Citation from OR, Series I, Volume 35, Part II, Series 66, pages 266-7.)