150 years ago: Colonel Serrell probing the marsh

Earlier this week I mentioned examinations aimed at place a battery in the marshes behind Morris Island in late July 1863.  Let me follow that up with details about how the engineers surveyed the marsh and what they found.  Colonel Edward Serrell, 1st New York Engineers, recorded those details in his journal of operations on Morris Island, incorporated into his official report.  The survey technique was simple and straight forward.  The team used 30 foot long, ¾-inch diameter iron rod:

The extreme edges of the swamps on the small creeks are hard, and frequently filled with oysters and oyster shells, but at a few feet from the water they become very soft, and within 10 or 12 feet the mud will not afford foothold for a man.

In these marshes, back from the harder edges of the creeks, the mud is from 18 to 23 feet deep, generally about 20 feet deep. It is so soft that the weight of the sounding iron will carry it down 8 or 10 feet, and a man can with one hand push it the remainder of the distance.

Down below the mud was hard packed sand.  Serrell went on to describe the surface features of the marsh:

On the mud there is a growth of very coarse grass, Spartina glabra and Uniola spicata, which is 4 or 5 feet high. It does not, however, form a sod, and the roots are not deep, but fine; they afford but little resistance to anything sinking through them. Extreme high water covers the surface of the mud.

Geologically the marsh is held to be sedimentary deposits of the very finest particles, brought down by the fresh-water streams, and are mostly vegetable. The blowing sands from the outer beaches, which are less recent in their formation, are sometimes mixed with the mud.

The resistance is increased by quantities of small shells, Auri-cola bidentata and Littorina irroratus, and occasionally muscles.

In other words, a lot of this stuff:

And this:

Crawling with these:

Hey, I like to touch all the bases… not just the cannon blasts and gleaming bayonets.  But you get the picture.

Serrell described the marsh mud in terms of its load bearing capacity:

A man’s foot, having a surface of from 30 to 35 inches, and sustaining a weight equal to 150 pounds, would sink into the mud 18 to 25 inches every step, and, if these were not made with some rapidity, much deeper. Two elements are involved here not in the other case; first, that of the motion of the foot, and, second, the suction of the mud against the leg, one tending to favor the penetration, the other retarding it; neither of these conditions applied where the load was static and rested on the surface.

Yes, things will sink into the mud. Which is not a good thing.  Furthermore, the mud’s consistency was that of jelly (Serrell’s word, mind you.)  Any movement sent vibrations out.  Men working on top of a plank would often send out vibrations over hundreds of feet across the surface.

But Serrell countered those issues with some practical observations:

In the case of a man attempting to walk, it was shown that, under the conditions he presented, something like a force of 500 or 550 pounds to the square foot could not be sustained by the marsh, but here there was the heavy weight of the body brought on the small point of the toe, or the side of the foot, or upon some other part of the sole of the shoe, in motion. If a battery was to be built, so long as the guns were not fired the forces would essentially be static, and the condition of rest become an important element in the calculation.

Reasoning a platform could be built on the marsh, Serrell then focused on the other problems – how to place such a platform on the marsh and how to deal with vibrations created when the gun fired.  We’ll look at that in the next installment on the Swamp Angel.

(Citation from Serrell’s report, OR, Series I, Volume 28, Part I, Serial 46, pages 230-2.)

Battery Brown and a Burst Parrott on Morris Island

Another of the heavy batteries constructed early during the work on Morris Island was Battery Brown.  Like the advanced gun on Battery Hays, Battery Brown’s guns were sited to fire on Fort Sumter.  On July 26, 1863 “began, on the right of the second parallel, by order of the general commanding, the construction of Battery Brown, for two 8-inch Parrott Rifles, intended to be employed in the demolition of Sumter.”

In his journal, Major Thomas Brooks recorded Sergeant Walter Smith, New York Volunteer Engineers, supervised the construction.  Sergeant Smith completed the parapet and epaulement by July 28. This gave the battery an L-shaped appearance, with the epaulement providing flank defense from the Confederate batteries to the west.  Platforms to support the heavy guns and carriages took a little longer but were completed on August 1.

The map section below shows Battery Brown just left of center.

BatteriesRight2ndParallel

Battery Brown took advantage of the large bombproof to the left (west) of the position.  Numerous splinter-proof shelters lay around the right section of the parallel, several of which were used to load shells for the battery.  To the front a battery of 12-pdr field howitzers covered the ground in front of the second parallel, should the Confederates attempt a sortie.   A profile, along the line annotated a-a’ on the map, included the howitzer position along with Battery Brown.

BatteryBrownProfile

Notice the palisading to the front of the howitzer battery (on the right).   The profile includes one of the splinter-proofs, on the left.  The note in the center reads, “Anchoring of sand-bag revetment consisting of upright stakes connected by wire.”  Brooks indicated iron gabions filled with sandbags fixed the embrasures for the guns.

On August 2, Brooks reported the first 8-inch Parrott mounted.  The second came days later.  But the guns remained silent until mid-August, as the Federals stockpiled ammunition and waited completion of the other batteries.  The guns participated in the first great bombardment of Fort Sumter starting on August 17.  The distance from the guns to Fort Sumter was 3,560 yards.  The range to Battery Gregg was 2,170 yards.  And to Fort Wagner was 830 yards.

But this battery was ill-fated from the start.  During the bombardment, the platforms sank A gunner broke a gimlet off in the vent of one 8-inch Parrott, putting it out of action for three days.  A few days later, the same gun perhaps, burst at the vent, blowing out the breech and throwing the gun forward across the parapet.  The bursting likely occurred on either August 24 or 26 (although could have been September 5). The gun was on the left side of the battery.

This photograph abounds with details.  There are accouterments hung from the braces for sandbags.

BatteryBrown1A

Hey, a bullseye canteen!

Count the bolts in the upturned carriage.

BatteryBrown1B

And there is the “upright stakes connected by wire.”

BatteryBrown1C

Notice the wire runs under the horizontal beams, presumably connecting to stakes on the other side of the parapet.

But what confuses me a bit are these fellows in the background:

BatteryBrown1D

Would they be sitting out there while the Confederate sharpshooters were active from Battery Wagner?   Or was the photo taken after the fall of Battery Wagner?

Regardless, I’d like to see what they are looking at – be it activity in the siege lines, Confederate fortifications, or out in the channel.  Perhaps a panorama of the war at Charleston’s harbor entrance.  If the photographers knew about us, looking at these precious few photographs, 150 years later, would they have taken more photos, or selected different vistas?  Oh, if we could just go back in time with one little point-and-shoot!

(Base photograph used is part of the Library of Congress Collection, call number LC-B8156- 39 [P&P].)