Federals convert the Rebel bastion: Battery Gregg becomes Fort Putnam

OK, Morris Island Monday, so back to Charleston, South Carolina.

When the Federals took possession of Batteries Wagner and Gregg on September 7, 1863, they faced a tactical dilemma.  The Confederates had carefully modified both fortifications to face south at the Federal threat during the long summer siege.  The earthworks featured high walls, traverses, bombproofs, and gun positions to resist the heavy rain of projectiles from the parallels on land and the ironclads at sea.  The Federal engineers had to “turn” those works to face Fort Sumter, Sullivan’s Island, James Island, and, ultimately, Charleston.  But after the digging of August and September, the Federal engineers were perhaps the best in the world at moving beach sand around for military purposes.

Battery Gregg required the most modification to serve the new purposes.  The Confederates had first constructed works on Cumming’s Point in the winter of 1861 to face Fort Sumter.  But by the spring of 1863, the works faced eastward over the Main Ship Channel.  As mentioned previously, the battery mounted three guns during the ironclad attack of April 7.  After that action, General P.G.T. Beauregard directed a fourth gun placed in the battery to strengthen the entrance defenses.  But when the Federals occupied the southern end of Morris Island in July, Battery Gregg required modifications to protect against the fires of those heavy guns in the siege lines.   Federal maps drawn during the siege show a “J” shaped trace:

BatteryGreggCS

I’ve not seen a detailed engineer’s plan for the battery, so let me offer my “best educated guess” as to the layout at the time of the Confederate withdrawal:

BatteryGreggCSTrace

The works featured four sea-facing gun pits with a large bombproof.  Flank protection reached out to the seashore on both sides of the main battery.  At least two mortar positions sat in the “tuck” of the “J”.

Of course none of this would work for the Federal’s intended use.  Work started almost immediately to convert Battery Gregg.  And as with the Confederate version of the works, I’ve yet to locate a proper engineer trace depicting the Federal modification.  Only large scale maps:

BatteryGreggUS

But even at this scale, clearly the Federals enclosed the back of Battery Gregg. Confederate observers noted by September 11 at least two Columbiads (captured guns most likely) were in battery in their former works.  Despite harassing mortar fire from Sullivan’s and James Islands, the Federals worked quickly to put up more guns.  Within days, some of the light Parrotts were responding with fire against Fort Sumter.

By mid-October, the Federals renamed the work in honor of Brigadier-General Haldimand Putnam, killed in the second assault on Battery Wagner on July 18.  Battery Chatfield, named for Colonel John Chatfield who was mortally wounded in the same attack.  Ultimately Battery Wagner became Fort Strong, named for Brigadier-General George Strong, also mortally wounded in the July attack.

In lieu of engineering diagrams, there are a large number of photographs of Fort Putnam for reference.  This photo shows the works shortly after capture:

The Federals had already cut out the front of the old gun positions, and were adding embrasures to the new facings.  There’s even a Confederate columbiad laying in the works (I’ll promise a good photo analysis post follow up).  Confederate palisades remain around the fortification.  A lot of details lead me to believe this photo was taken around the same time Haas & Peale took the photos of Fort Sumter’s damage.

Other photos, taken later, show rows of guns inside the converted Fort Putnam:

These guns were facing Fort Sumter.  With the mound in the right background, this must be part of a line built across the hook of the “J”.  Another photo from the east end of that line (perhaps taken at a different time) shows a large Parrott mounted where the angles joined.

Other photos show heavy Parrotts and columbiads in positions with high traverses.

Stacks of ammunition ready for use there.

Another photo shows a well protected walkways between the gun positions:

Gone are the sandbags of the siege, replaced by grass and sod.

Using the photos (and there are many more than I’m using for this post) and other background information give me enough information to offer this guesstimate of Fort Putnam’s layout:
BatteryGreggUSTrace

Again, not saying this is “the way it was.”   Just offering it up for consideration.  Every time I look over the Fort Putnam photos I found some detail that helps piece together the works.  And I still hold out that somewhere an engineer’s diagram will surface showing the real trace of this fort.

At any rate, 150 years ago the engineers who had laid out the parallels and directed the siege of Battery Wagner were working just as hard to modify the former Confederate works.  Far from remaining a quiet backwater of the war, Charleston would remain under siege.

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