“Conformable to your request, six 100-pounder Parrotts will be loaned.”: Naval reinforcement for Fort Sumter bombardment

A subtle point made by Lieutenant-Colonel William Ames in his in-progress report on the Third Major Bombardment, on July 27, 1964, was the attrition rate of the heavy Parrott rifles.  These guns – the 6.4-inch (100-pounders), 8-inch (200-pounders), and 10-inch (300-pounders) – not only threw the greatest weight, but were more frequently used in the Third Major Bombardment than their smaller brothers.   The loss of one gun burst and two out of action for repairs put limits on the sustained rate of fire against Fort Sumter.  Another approaching limitation on the firing rate was the supply of ammunition.  Having expended over 6,000 rounds by month’s end, even the large stockpiles on Morris and Folly Island were drained.

If the pace of fire slackened, the Confederates would have more time to repair.  Major-General John Foster could not have that.  He wanted to knock the fort down.  More so, Foster wanted to increase the pace, if possible, by adding more guns to the bombardment.  Reluctant to wait for more shipments from the north, he inquired with Rear-Admiral John Dahlgren on July 30, 1864:

I have the honor to request the loan of six 100-pounder Parrott guns, to be placed in a new battery erected on Cumming’s Point. I also beg leave to say that I will avail myself of your offer of some 9-inch guns for the battery at Spanish Wells, and will send for them in a day or two. I shall be obliged to borrow of you the ammunition for these guns, as we have none.

Dahlgren, in the spirit of good joint operations, responded promptly:

Conformable to your request, six 100-pounder Parrotts will be loaned to you, and are at your disposal when it suits your convenience to send for them. I expected to have obtained the 9-inch guns from the Wabash, but she has left this port, and I have required on the Bureau for some. When they arrive I shall be glad to meet your wishes.

On paper there were “Army” and “Navy” models of these large Parrott rifles.  But the only notable difference between the models were the markings.  All Parrotts larger than 5.2-inch (30-pounder) had blade-type cascabels with breeching blocks.  Sight arrangements varied for mountings on ironclads, pivot batteries, or army siege carriages.  But those were fittings modified locally by artificers.  These were guns which Foster could put into battery without delay.

As for the 9-inch guns requested, eventually the Navy loaned Dahlgrens.  But of a larger caliber, as captured in a wartime photograph:

Unlike the Parrotts, the Dahlgren gun required a wooden carriage, seen here.  Looks rather out of place sitting on a wooden platform in the beach sand.

(Citations from OR, Series I, Volume 35, Part II, Serial 66, pages 200-2.)


Photo Analysis: Morris Island Ordnance Depot (Part I)

During operations on Morris Island, the Federals maintained a busy ordnance depot on the south end near Lighthouse Inlet.  If there was ever a place and time for an artillery-focused blogger to use a time machine….  Just imagine the “stuff” laying out on the beach – cannons, burst cannons, carriages, implements, projectiles, …. Short of a time machine, several photographs exist in which the lens turned that way.

One of those photos – the first in what I hope to make a series over – was taken by Samuel A. Cooley, the “Photographer of the Department of the South.”

[Unknown location. Wagons and camera of Sam A. Cooley, U.S. photographer, Department of the South] (LOC)

There’s his crew, with all the field equipment, camera, and a glass plate at the ready.  Cooley photographed scenes along the South Carolina, Georgia, and Florida coasts.  Cooley is most known for his photos of Fort Sumter after its capture in 1865.  From what I gather, Cooley’s photographic activities came to Morris Island in December 1863.  He maintained a studio there through the end of the war.  So this photo…

… might have been from anytime from that point on to the end of the war.  (The stereo-view is also digitized in the Library of Congress collection.)

For years I’ve been drawn to this photo because of the “stuff” scattered around in a semi-organized manner.  None of the neat stacks of equipment or carefully aligned rows – all indications of a real ordnance depot supporting an active campaign.  At times, I’ve entertained this depot was on Folly Island instead of Morris Island.  But the more I try to pin things down, the more elusive the confirmation is.  For now, I’ll settle and suggest this is a photograph of the ordnance depot on the south end of Morris Island.


I’ve never seen any documentation that might narrow down the location to a specific spot on the map. To my knowledge, no diagrams of the ordnance depot exist.  So I don’t know where exactly to put the “star” to locate this photo.  Given that shortfall, I’ll present some of the clues I’ve found in the photo in hope that you readers might pick up the challenge.  I usually spend time looking for markings, flags, or other indicators of a unit designation.  With all that equipment in view, are there any markings?

Starting furthest back on the right, there’s this thing…


That’s a heavy sling cart.  Just like the one on display today at Fort Pulaski.

Ft Pulaski 3 Aug 11 1336

Another set of those appears on the left side of the line:


While offering no markings, the presence of those heavy sling carts indicates the Federals were handling heavy guns, like those big Parrotts.  So some corroborative evidence, but nothing definitive.  In between the sling carts are caissons and field forges more closely associated with field batteries.


The only “mark” that stands out is an “8” with a laurel around it.  Again, nothing to narrow down to a particular unit.  Note, however, on the left the siege carriage limbers.  Again, corroboration that both field and siege guns were supported out of this depot.

Another way to narrow down the location is review of the background.  In this photo is a single story building, arranged as if a workshop.


Only a few tents are in view.


In the distant background are treelines.  Very typical coastal treelines of that time, with the base of the trees in silhouette.  Indicates some human activity which kept the brush clear.


That might be Black Island.  If so, the even more distant treeline behind the workshop would be James Island and the Confederate batteries.

OK, with that swag taken to narrow down the photo’s location and orientation, let’s turn to the “stuff” in the foreground.  Lots of projectiles…. lots of types of projectiles…


Some are easily identified as the Parrott Pattern.  There’s a strapped smoothbore projectile (don’t let the shadow fool you) in the stack.  And falling off the back looks to be a Brooke projectile with bourrelet (ring around the body just behind the ogive, or “nose”).

Looking at the other stack further up in the photo…


More Parrott projectiles, but one of those to the left looks like a Hotchkiss with lead band standing out as an off-shade.

Between the stacks of shells are a few “litters,” or carriers used by the troops to move shells.


These are laying upside down.  But in many photos of the batteries, these are sitting behind the guns, looking like short legged tables.

Just behind the carriers is this ratchet roller for use in handling the guns.


I’m at a loss to find a photo with this particular part in use.  Looks like this one has lost one “tooth” at some point.

Other items in the foreground which draw the eye are rows of wrought iron carriages.


These were the type seen frequently in photos of the Army’s Parrotts in position on Morris Island.  Certainly enough on hand to sustain a long campaign.  Other photos of the depot show these with a better view for details.  What I’d point out here is the difference between the inside of the traversing wheel (upper center) and outside (lower center).  The inside of the wheel had “spoke” reinforcements.

A nice row of 30-pdr Parrotts stood just behind the carriages.


The sad part here is the resolution, even digitized, does not allow us to read the muzzle markings.  At least a battery’s worth of the 30-pounders there.  Later production, as there is no muzzle swell.  And these also appear to have the shorter trunnions, which don’t use all of the capsquare on the carriage. The shorter trunnions reflected the Federal preference for wrought iron carriages.

In front of those Parrotts were rails for wooden carriages.


Again, evidence pointing to the use of captured Confederate guns.  And if you are looking for more evidence, look behind the Parrotts:


Yes, an old carronade of the type used by Confederates as flank defense in Battery Wagner.  Maybe a 42-pdr?  Or 32-pdr? It appears to be mounted on a modified field carriage with no cheeks.  Now there’s a cannon with a story to tell!

Explosion in the turret: Parrott Rifle problems afloat

Parrott Rifles carry a bad reputation for failures.  I’ve mentioned and offered illustration of some failures on Morris Island (and there is more to come when time permits).  But some of those big Parrott rifles served on the monitors off shore.  The Army’s gun crews had the opportunity to place a barrier between them and the gun when firing.  As happened with the Swamp Angel, the Army’s crews could even fire the gun when failures were predicted and expected.  the Navy’s crews were in a closely packed space with little margin for safety.  On Nobember 2, 1863, the crew manning an 8-inch Parrott rifle on the USS Patapsco suffered a tragic incident, which easily might have proved catastrophic.  A report from Commander T. H. Stevens, commanding the Patapsco, offered a few details:

I regret to inform you that during the bombardment of Sumter this day William Cotter and John Morris, landsmen, were unfortunately killed by premature explosion of the rifle gun.

How the accident could have occurred I am unable to determine, as the gun had been fired but once since it had been washed out thoroughly, and the cartridge had just entered the gun when the explosion took place.

The two men killed were the second sponger and second loader of the gun.

Four other men in the turret suffered injuries from the blast, including Lieutenant-Commander Frank Bunce.  The Patapsco had fired ten XV-inch shells and sixty-three 8-inch Schenkle shells up to that moment of the day.  But after the explosion, the monitor cleared off from Fort Sumter and lay back in the channel.

From the description, my guess is the failure was due to an unextinguished ember.  Rifled bores offered several angles in which such embers might avoid the sponge.  The one pound charge of a 3-inch rifle is dangerous enough, but the sixteen pound charge of an 8-inch rifle is exponentially more so.

The Patapsco returned to the firing line on November 3, sending a dozen XV-inch shells and thirty-three 8-inch Schenkle shells towards Fort Sumter.  However, the monitor shuttled back to Port Royal for refit the next day.  This was not directly due to the premature explosion, but more so due to fouling on the hull.  (And while off the gun line, the Patapsco was used in experiments related of John Ericsson’s obstruction removing device – this time with explosive charges.)  While no direct order indicates the 8-inch Parrott was removed, Rear-Admiral John Dahlgren noted, “It was necessary to replace the rifle gun of the Patapsco,” in a November 4 report.  In a post-war report to Congress (connected to an 1878 testimony by none other than Norman Wiard), the Navy recorded an 8-inch Parrott from the Patapsco which failed:

Navy Parrott rifle gun, No. 6 (150-pounder, caliber 8-inch), cracked in action, on the monitor Patapsco.

With no date given, the connection is speculation on my part.  But given the low registry number recorded and damage to the muzzle, there’s at least circumstantial evidence this was the same gun replaced at Port Royal.  So perhaps the explosion on November 2 weakened the gun to a point that later firings produced a crack, leading to replacement.

Another issue with Parrott Rifles, and with rifled guns of the Civil War in general, was premature explosion of the shells.  A table recording the fires from the USS Lehigh over October 26 to November 4 provided interesting comparisons between her Parrott and big XV-inch gun:


The premature explosion rate of Parrott rifles was 6% over that time.  That of the smoothbore was slightly higher at 8%.  But these are “damned statistics” with a very low sampling for the smoothbore.   No other returns offered a detailed list of shots fired with mention of premature explosions.  Nor do the returns from the Lehigh offer details about the fuses selected for the bombardment.

Questions about the Parrott rifle reliability remained at the fore of ordnance officers ashore and afloat.  For naval officers, the question was much more sensitive due to the nature of the employment in the turrets.  In spite of those concerns, the big rifles remained on the monitors and continued to do damage to targets like Fort Sumter.

(Citations from ORN, Series I, Volume 15, pages 78, 79, and 82.)

Bombardment of Fort Sumter Continues, October 29-30, 1863… and Confederates fire on a pile driver

The bombardment of Fort Sumter, started on October 26, 1863, continued through this week 150 years ago with an increase in the number of shots fired by the Federals. Colonel Alfred Rhett, commanding the garrison at Fort Sumter, began his report for October 30, 1863:

The haze prevents an accurate report of the fleet this morning. Seven hundred and seventy-nine shots were fired at the fort yesterday; 80 of these passed over. Their effect was to cut away all of the top arches on the sea face, and to make that face and the gorge easy of access throughout their whole extent. Two hundred and sixty shots were fired last night, 80 of which missed. This makes 1,039 of all calibers, from 15-inch mortars and 300-pounder Parrotts downward.

From the present direction of the enemy’s fire, I am led to conclude that he wishes to avoid injuring the northeast and city faces of the work as much as possible. I think he will try an assault.

Rhett went on to assess the fort’s chances against an assault.  While the guns on Sullivan’s Island could cover the eastern faces, nothing covered the gorge wall.  He wanted a guard boat posted south of the fort and one of the gunboats from the Charleston squadron placed between Sumter and Fort Johnson to flank any attack on the gorge wall.

Later in the day, Rhett reported 955 shots fired at Fort Sumter during daylight on October 30, with 68 missing.  Another 68 fell in and around the fort after dark, giving the total for that day of 1,020 shots.  Of these shots fired, 443 were from rifled guns with 61 missing; 86 shots from the monitors, all of which hit; and 373 were mortar shells with 120 missing.  Rhett’s numbers don’t add up, but the breakdown of fires, and accuracy, is worth noting.

Battery Simkins fired 31 mortar shells and five 8-inch shells from its columbiad against the Federal batteries.  A Brooke gun at Fort Johnson fired ten shots at Morris Island with dismal results attributed to bad fuses.

Activity on October 30 was not confined to Fort Sumter.  A new target attracted Confederate fire from James Island:

About 11 a.m. a floating pile-driver of the enemy came to a point in the creek to the southwest of Black Island, and commenced to drive a pile. Fire was opened upon her from Redoubt No. 1, with an 8-inch navy shell gun and a 30-pounder Parrott. Eight shots were fired from the former gun and 10 from the latter, when the vessel withdrew out of range. Only about one-half of the shells burst, and the timing of the fuses did not appear to be very accurate.

The range of these shots was between 1 ¾ and 2 miles ( 3080 to 3520 yards).  The opening ranges for the later shots are due to the withdrawal of the pile driver. See the green line on the map below for my estimate of the declination of those fires.


By comparison, the Federal batteries on Cumming’s Point were firing at ranges between 1350 and 2500 yards… with heavier projectiles, mind you.

Supervising the fires from Redoubt No. 1, Major Edward Manigault recorded particulars of each shot fired.  Starting with the 8-inch navy shell gun, all with an 8 pound powder charge:

  • 1st shot – 12° elevation, 10 second Navy fuse, 1 ¾ mile range – Burst high and short.
  • 2nd shot – 14° elevation, 15 second Navy fuse, 1 ¾ mile range – Fell left about correct distance, no burst.
  • 3rd shot – 14° elevation, 15 second Navy fuse, 1 ¾ mile range -Burst high and right.
  • 4th shot – 15° elevation, 15 second Navy fuse, 2 mile range – Fell right, did not burst.
  • 5th shot – 16° elevation, 15 second Navy fuse, 2 mile range – Burst high and left.
  • 6th shot – 15° elevation, 15 second Navy fuse, 2 mile range – Burst high.
  • 7th shot – 15° elevation, 18 second Navy fuse, 2 mile range – Good line shot, very little short, Selma fuse.
  • 8th shot – 15° elevation, 17 second Navy fuse, 2 mile range – To left, did not burst, Selma fuse.

And for the 30-pdr Parrott, all with 3½ pound powder charge, with fuses supplied from Richmond:

  • 1st shot – 8° elevation, 8 second fuse, 1 ¾ mile range – Fell right and nearly at proper distance.
  • 2nd shot – 9° elevation, 8 second fuse, 1 ¾ mile range – Good line shot but burst too soon.
  • 3rd shot – 10° elevation, 11 second fuse, 1 ¾ mile range – Burst high and to the left.
  • 4th shot – 12° elevation, 15 second fuse, 1 ¾ mile range – Fell a little left and far enough.  Did not burst.
  • 5th shot – 11° elevation, 13 second fuse, 1 ¾ mile range – Good line but little short, Very close apparently.
  • 6th shot – 12° elevation, 13 second fuse, 2 mile range – Fell to right. Did not burst.
  • 7th shot – 11 ½° elevation, 13 second fuse, 2 mile range – Burst a little high but apparently threw fragments around the pile driver.
  • 8th shot – 11 ½° elevation, 13 second fuse, 2 mile range – McEvoy igniter, little short, excellent line.  Did not burst.
  • 9th shot – 12° elevation, 12 second fuse, 2 mile range – Fell right. Not very good. Did not burst.
  • 10th shot – 12° elevation, 11 second fuse, 2 mile range – McEvoy igniter, premature explosion.

The McEvoy igniter was the invention of C.A. McEvoy of Richmond, Virginia.  In short, the igniter used inertial forces to slip a friction primer, which then lit a paper time fuse.  Clearly there were some kinks to work out with those fuses.

There you have it… I hope you were entertained with the “Battle of the Pile Driver.”  But in all seriousness, the high number of failed shells within the eighteen fired is indicative of the problem described earlier with respect to fuses.  The Confederates engaged at longer ranges, where the margins for success were slimmer.

(Citations from OR, Series I, Volume 28, Part I, Serial 46, pages 152 and 631; Manigault’s record of shots fired is from Siege Train: The Journal of a Confederate Artilleryman in the Defense of Charleston, edited by Warren Ripley, Charleston: University of South Carolina Press, 1986, page 72.)

Cannon Walk Around: The Keokuk XI-inch Dahlgren

Since we are now well acquainted with this gun’s story, time for a “walk around.”

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Keokuk Gun in Charleston’s White Point Garden

The gun is one of fourteen surviving XI-inch Dahlgrens, including two from the USS Monitor, in their original form (another nine survivors were altered to 8-inch rifles) out of a production run of 465.  As mentioned in the earlier post on XI-inch Dahlgrens, the Keokuk gun has an altered muzzle.

Charleston 4 May 10 067
Muzzle of Keokuk Gun

I’ve not found a primary source to confirm this, but most accounts indicate the sides of the muzzle swell were shaved down to permit easier passage through the Keokuk’s gun ports.  Mounting the gun on an open barbette, the Confederates certainly had no need to reduce the muzzle.

The chase of the Dahlgren tapers evenly and proportionally back to the “shoulders” of the gun.  Just before the trunnions, the gun diameter begins to increase much more rapidly to meet the cylindrical reinforce. The trunnions are 9 inches long and 10 inches in diameter.  The rimbases are just under 13 inches in diameter, with a face separation of 32-inches.

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Trunnions, rimbases and “shoulder” of Keokuk Gun

Notice the front sight block on top, between the trunnions.  That front sight matched to the rear slide sight on the back of the breech, seen here between two lockpiece blocks.

Charleston 4 May 10 070
Reinforce, lockpiece blocks, and rear sight

This view accentuates the cylindrical reinforce.  The rear sight is between, and to the rear of, two lockpiece blocks.  Notice only one is cut for mounting the lockpiece.  In a closer view, you can see the vent hole in front of that block.

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Upper breech of Keokuk Gun

Recall the USS Keokuk fired but three times on April 7, 1863.  After recovery, the Confederates likely, with a mind to conserve powder, fired the gun only when necessary.  So no surprise the second vent and lock piece were never mounted.

The breech profile confirms to Dahlgren’s hemispherical design.  The blade cascabel features a set of “jaws” to which the block is not permanently fixed (either by welding or corrosion).  So the breeching loop is a complete circle.

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Breech profile of Keokuk gun

The cascabel sticks out 12.5 inches from the breech.  Visible on the bottom of the blade is the piercing for the elevating screw.

Just behind the trunnions is the cylindrical reinforce, roughly 32 inches in diameter.  This view from underneath the breech also shows the profile of the rear sight block.

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From underneath the Breech

You may have noticed, looking at the trunnions and the post under the breech, the carriage for the Keokuk gun does not exactly fit the gun.

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Post on carriage for Keokuk gun

The carriage is not the type used for the gun during the Civil War.  Photographs taken in 1865 show the Dahlgren on a wooden carriage.  Instead this is a wrought iron carraige used for Rodman guns.  The stamps on the carriage announce its manufacturer – Union Iron Works of Buffalo, New York.

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Union Iron Works stamp

The works were one of the rolling mills built during the war.  A photograph from the turn of the last century shows the Dahlgren, along with a 10-inch Confederate columbiad, on similar (if not the same) wrought iron carriages not far from where they stand today.

There’s no mistaking the “shaved” muzzle of the Dahlgren.

A historic gun along the seawall, with a rich story to tell.  If you pause for a moment, you might catch a salty breeze coming in from the sea.

The “all purpose” shell gun: XI-inch Dahlgrens

If pressed to name the most important, or most useful, weapon in the Dahlgren family, I’d make the case for the XI-inch Shell Gun.  The Navy employed that weapon in every possible guise during the Civil War (and beyond).  The weapon served widely across the fleet in some of the most historic engagements.  The USS Monitor carried XI-inch guns into action at Hampton Roads on March 9, 1862.  Other ironclads employed XI-inch guns in the attack on Fort Sumter on April 7, 1863.  XI-inch Dahlgrens of the USS Kearsarge smashed the CSS Alabama in the Battle of Cherbourg on June 19, 1864.  I’d make the case the XI-inch Dahlgrens were the most “storied” of the family.


The XI-inch gun requirement rose from practical considerations of the advances in ship propulsion technology in the 1850s.  In his book, Shells and Shell-guns, published in 1856, John A. Dahlgren wrote:

The earliest steamers were driven by the sidewheel, and so continued for man years later.  This arrangement conflicted directly with the system of broadside armament, both as regarded the number of guns and their position.

In the first place, it was impossible to carry the customary proportion of pieces in a vessel of this description, because the steam power occupied so much of the space commonly allotted to stowing provisions and water, that the crew required for a full broadside, could not be provided for.  Therefore, it was necessary to reduce the number of men, and as a consequence, the number of cannon; independently of which, the latter could not be accommodated in the broadside, because the huge wheels and their fixtures not only covered much of its extent, but they interfered with the training of those guns for which there was room.

Thus Dahlgren suggested the largest possible caliber shell guns be mounted on pivots at either end of the ship.  Such worked around the issues mentioned and at the same time met the long standing American preference to carry the heaviest possible weapons into the fight.  So Dahlgren added the 11-inch caliber to the shell guns of his design.  He considered that caliber the heaviest which could be worked at sea.


The first production batch came from West Point Foundry in 1856.  Of these early guns, at least one was expended in extreme proofing.

However, the XI-inch shell gun met with some skepticism among the Navy’s ship captains.  After all, a XI-inch shell weighed some 136 pounds!  To settle this, Dahlgren went to sea with one of the XI-inch guns on the training ship USS Plymouth in 1857.  Successful trials convinced the Navy’s senior officers that crews could work the XI-inch guns.  Mounted in pivot, the gun required a crew of 25.


The XI-inch guns also served as broadside guns, most notably on the USS New Ironsides, where the screw propulsion system removed the limitations Dahlgren noted in the pre-war discussions.

At the start of the Civil War, the Navy was just beginning to equip ships with the heavy shell gun.  West Point Foundry delivered 50 by the end of 1862.  Included in that lot were numbers 27 and 28 which served on the Monitor. Number 40 went to sea on the Kearsarge.

XI-inch Gun on the Kearsarge

In 1862, other vendors received contracts for XI-inch shell guns.  During the war, Fort Pitt Foundry cast 70; Cyrus Alger provided 89; Builder’s Foundry of Providence, Rhode Island delivered 100; the firm of Hinkley, Williams and Company of Boston, Massachusetts added 100; Seyfert, McManus and Company’s Scott Foundry produced 49; the Portland Locomotive Works in Maine cast four before shifting back to engine production; and likewise the Trenton Locomotive Company in New Jersey dabbled with naval ordnance, but only delivered three guns.  Overall the Navy received 465 of the XI-inch Dahlgrens.

The XI-inch gun design conformed to Dahlgren’s “soda bottle” exterior shape.  The guns were cast solid with excess metal around the chase, then bored out.  As the table above indicates, the bore ran 131 inches including an 11 inch chamber.  The chamber used a modified Gomer profile, being rounded at the bottom instead of flat.  The only major variation among the castings was with the muzzle.  Contemporary records indicate the first deliveries had a “bulb muzzle,” describing the shape of the muzzle swell. Later deliveries used a “tulip muzzle.”  Yet many survivors have no muzzle swell at all or at least part of the swell shaved to clear the firing ports.

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Muzzle of XI-inch Gun from the Keokuk

The muzzle alterations continued postwar when the Navy ordered some guns converted to rifles.

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XI-inch Gun converted to 8-inch Rifle

The XI-inch guns served as pivot guns, broadside guns, turret guns, and even seacoast defense guns during the Civil War.  In short, every conceivable position one might use a 16,000 pound gun!

The Dahlgren “family” of smoothbore shell and solid shot guns

Earlier I mentioned some connections between the biggest of the Dahlgren guns and the Army’s Rodman guns. These weapons were contemporaries, as of course were the inventors – John A.B. Dahlgren and Thomas J. Rodman. But while the Army’s Rodman guns were designed almost exclusively for seacoast defense, Dahlgren’s designs covered practically all the Navy’s requirements. Given the varied nature of such requirements, the term “Dahlgren” might refer to several different types.

We can generally group the Dahlgrens within three “families” – the boat howitzers, the heavy smoothbores, and the heavy rifled guns. I’ve discussed the boat howitzers in detail (but should return to complete the discussion of the various subtypes at some point). The rifled Dahlgrens, I must likewise table for the moment as they don’t factor yet sesquicentennial-wise. I’ve already discussed the IX-inch and XV-inch Dahlgren guns. So it is time I introduce the family of heavy smoothbores:


I’ve organized this diagram to show the three generations of Dahlgren’s heavy smoothbore guns: pre-war, wartime, and post-war. The vertical columns show the various calibers of these heavy smoothbores. Again, notice the use of roman numerals with the weapon designations, which was the Navy’s practice at the time.

Within those generations are four sub-types: the original shellguns (blue-gray), wartime solid-shot guns (tan), the turret guns for the ironclads (gray), and the postwar derivatives (gold).

First, the original shell guns. When discussing the IX-inch shell guns used by Confederates at Charleston in 1861 (and which were still there in 1863), I offered this table comparing the particulars of the Dahlgren Shellguns:


These were the four main calibers of shellguns entering service in the years just before the Civil War. As the family diagram shows, there was a 32-pdr shellgun. But this was apparently just a developmental weapon, with few produced. The VIII-inch guns went through a design change during the war, resulting in a heavier version. Production run of that heavier VIII-inch shellgun was 351, from 1864 to 1867.

As their name implies, the shellguns featured a design optimized for firing shells. There’s a long story behind the employment of shells for naval ordnance. The short version – by the first half of the 19th century fuse, projectile, and cannon design reached a point that the shell was a viable option for naval use. While traditional solid shot, depending on raw kinetic energy, could damage wooden ships, the shell’s explosive power offered certain advantages. Dahlgren designed these shellguns to fire primarily shells, with the option to use solid shot when needed.

The shellguns served the Navy well, particularly the IX- and XI-inch guns. These included perhaps the most historic of all the guns used in the Civil War, the XI-inch guns in the turret of the USS Monitor.

CW Confrence 10 Mar 12 112
IX-inch Dahlgren from the USS Monitor

And of course there were a few other famous Dahlgren shellguns, also of XI-inch caliber.

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But we’ll get to the guns of the USS Keokuk in due time.

By mid-war, the Navy realized a requirement for guns which could fire solid-shot, along with the occasional shell (in other words, the opposite of the original shellguns). Consequently, the Navy’s Bureau of Ordnance designed a set of guns based on Dahlgren’s original design. The requirement for these guns was to fire solid shot against armored warships, with high durability in mind. Such accounts for the heavier weight.

At any rate, the solid-shot guns came in four calibers:

  • 32-pdr of 4,500 pounds. 379 produced between 1864-67.
  • VIII-inch of 10,000 pounds. Only one produced in 1864.
  • IX-inch of 12,280 pounds. Only one produced in 1865.
  • X-inch of 16,500 pounds. 29 produced in 1862-65.

The production figures offer an indication these guns were not entirely successful. The aberration being the large number of 32-pdrs produced. The need for weapons on smaller craft (river and inshore patrol) might account for a healthy production run. But what has been lost to time is why such production continued well after the war.

While the solid-shot guns were not deemed successful enough as anti-ironclad weapons, the big turret guns were. As mentioned in the post about the XV-inch guns, Dahlgren had some reservations about casting guns larger than XI-inch. So many of the XIII-, XV-, and XX-inch used the Rodman casting technique as a “hedge.” These joined the XI-inch shellguns in the early monitors. By war’s end, the preference was for uniform caliber armament in the turrets. The Navy received only eleven of the XIII-inch guns. The lone XX-inch gun produced during the war was not delivered to the Navy, but later sold to Peru. But as mentioned earlier, the XV-inch guns became the Navy’s standard turret guns (going through a few design revisions along the way).

And to close out the “family tree” of the heavy Dahlgren smoothbores, these weapons saw long post-war service. With the heaviest of the family holding an important position as the primary armament of the Navy’s vaunted ironclads, some XV- and XX-inch guns appeared with slight improvements. The last twenty XV-inch guns featured Army-style elongated hemisphere bore bottoms. Three additional XX-inch guns conformed to a revised, slightly smaller, design in 1866-7. But none of those saw active service.

The long line of Dahlgren smoothbores ended, much as with the Army’s Rodmans, with a conversion.

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Muzzle of XI-inch Dahlgren converted to 8-inch Rifle

Just over fifty XI-inch shellguns underwent an involved process with the aim to extend their usefulness a few more years. The modifications were done between 1876 and 1880. In addition to a rifled sleeve inserted into the bore, the guns also had their trunnions modified to retain the preponderance.

These heavy Dahlgrens served the Navy from the mid-1850s up to the eve of the 20th century. Although woefully inadequate at the time, a few of these old Dahlgrens were on the equally inadequate old monitors pressed into brief service during the Spanish-American War. After that time, just like the Army’s old Rodman guns, the Dahlgrens mostly went to scrap. But in a few cases, guns were salved for use as gate guards, bollards, or memorials. A fitting end for such long-serving guns.