Fort Pulaski: A Study of Massed Firepower

Years ago while touring Fort Pulaski with one of my fellow Army officers, I was asked the question, “Why should one study Fort Pulaski?”  My friend was looking at the visit from a professional aspect and thus searching for the lessons one might learn from the battle fought there in April 1862.   My answer was that on the surface, Fort Pulaski was a study in old weapons against old style defenses.  However, passing beyond that summary, the reduction of Fort Pulaski is a very good example where the principle of mass was applied directly on the battlefield.

In a separate post, at some point, I will break down the details of the investment, siege, and reduction of Fort Pulaski.   For now let me focus on the tactical deployment of the siege artillery.  Captain Quincy Gilmore (he was later made acting Brigadier General during preparations for the siege) first laid out the general concept in a report in early December 1861.  Gilmore refined the plan over the months, later providing a very detailed report of the operation.

Reduction of Fort Pulaski, from the OR Atlas

From the notes on the margin, and from Gilmore’s official report the composition (see note below) of these batteries and the range to their target is known to the last yard:

  • Battery Stanton.  Three 13-inch Model 1861 Seacoast Mortars. Range:  3400 yards.
  • Battery Grant.  Three 13-inch Model 1861 Seacoast Mortars. Range: 3200 yards.
  • Battery Lyon.  Three 10-inch Model 1861 Columbiads (Rodman) Guns.  Range: 3100 yards.
  • Battery Lincoln.  Three 8-inch Model 1844 Columbiads.  Range: 3045 yards.
  • Battery Burnside.  One 13-inch Model 1861 Seacoast Mortars.  Range: 2750 yards.
  • Battery Sherman.  Three 13-inch Model 1861 Seacoast Mortars. Range:  2650 yards.
  • Battery Halleck. Two 13-inch Model 1861 Seacoast Mortars. Range: 2400 yards.
  • Battery Scott.  Three 10-inch Model 1861 Rodman Guns and one 8-inch Model 1844 Columbiad.  Range: 1740 yards.
  • Battery Sigel.  Five 30-pdr Parrrott Rifles and one 48-pdr James (24-pdr siege gun, rifled).  Range:  1670 yards.
  • Battery McClellan.  Two 84-pdr James (42-pdr seacoast gun, rifled) and two 64-pdr James (32-pdr seacoast gun, rifled).  Range:  1650 yards.
  • Battery Totten.  Four 10-inch Model 1861 Seacoast Mortars.  Range:  1650 yards.

As the map indicates all these batteries stood on Tybee Island, firing over the South Pass of the Savannah River.  Plans to place other batteries further upstream and around the fort were tabled before the bombardment.  As events worked out, the additional batteries were not needed.  The photo below was taken standing on the banks of the Savannah River, about 300 yards east of where Battery Scott stood.   Just right of center is the Fort Pulaski flagpole.  And further to the right is the Cockspur Island lighthouse.   Range to the fort is just over 2000 yards in this view.

Savannah 5 May 10 155

Looking at Fort Pulaski from Tybee Island

Today the battery positions are bisected by U.S. Highway 80 or on private property.  This vantage point is part of a new wayside exhibit built-in partnership with a property development company and the National Park Service.

Orders to the batteries reflected Gilmore’s intent – a systematic reduction of the fort.   The orders were specific as to the powder charges, elevation, fuse settings, rate of fire, and projectiles.  Furthermore, each battery was assigned a specific target and desired effect.  From orders issued April 9, 1862 (recorded as General Orders No. 17 in Gilmore’s official report, OR, Series I, Volume 6, Serial 6, pp. 156-7):

  • Batteries Stanton and Grant (with mortars) fired over the south face of the fort with shells exploding upon impact.
  • Batteries Lyon and Lincoln (with columbiads) fired at high elevation to pass shells over the parapet landing on the inside of the north wall of the fort with shells exploding on impact.
  • Batteries Burnside, Sherman, and Halleck (with mortars) fired on the arches of the north and northeast face of the fort, with shells exploding on impact.
  • Battery Scott (with columbiads) aimed to breach the corner where the south and southeast faces joined.
  • Battery Sigel (with rifles) would also breach the corner, but only open fire after the Confederate parapet batteries were silenced.
  • Battery McClellan (with rifles) was also directed to the corner to breach the walls, but further instructed to focus between the last southeast face embrasure.
  • Battery Totten (with mortars) fired shells over the northeast and southeast faces of the fort, with instructions to focus on any Confederate battery that prepares to counter-fire.

The ranges for the breaching batteries was about double that recommended in the artillery manuals of the day, for smoothbore weapons.  However, experiments with rifled artillery, which Gilmore cited in his report, indicated breaching at those ranges was possible due to the improved technology.  And Gilmore massed his most effective weapons in an effort to breach the closest corner of the fort, with his other weapons firing in support with specific intended effects.

Savannah 5 May 10 271

30-pdr Parrott on Siege Carriage -Fort Pulaski

Prior to the siege of Fort Pulaski, none other than General Robert E. Lee, then commanding the coastal defenses of Florida, Georgia, and South Carolina at the time, considered the possibilities of a siege.  Recall that early in his career, Lee had directed the construction of Fort Pulaski.  So he knew the area and the fort well.  Lee commented to the effect that Federal batteries on Tybee Island could not breach the Fort’s walls, but they would make things difficult on the defenders.

Savannah 5 May 10 223

Fort Pulaski Parapet - Northeast Face

At about 8:15 AM on April 10, following a formal demand to surrender, Federal batteries opened fire upon Fort Pulaski.   Some of the Columbiads jumped off their carriages due to recoil, but were brought back into service.  And the mortar fire appeared unsatisfactory, with only one of every ten fired landing within the fort.  Yet by the evening of the 10th, the Federals had severely damaged the south-southwest corner, starting the breach. Federal mortars and one of the Parrotts fired at intervals through the night.

At sunrise on April 11th, all batteries resumed firing.  Within a few hours the breach was enlarged.  By noon two entire casemates were torn open.  Finally at 2 PM the fort’s commander, Colonel C. H. Olmstead, raised the white flag.  The breaching was completed with about fourteen hours of firing on both days.

Breach at Fort Pulaski

The Federals scored a victory at Fort Pulaski with the loss of only one man.  This was not by happenstance, but by design.  Gilmore described Confederate fire as “vigorous” but with little effect.  The Federal columbiads and mortars disrupted the Confederate gunners on the parapets.  Furthermore, the Federal batteries were placed in a way to exploit a geometrical disadvantage of the fort.  Only guns on the southeast face of the fort could directly engage the Federals without firing over their comrades.  Thus of the 48 cannon and mortars in Fort Pulaski, less than half were brought to bear on Tybee Island.

Savannah 5 May 10 259

SW Corner of Fort Pulaski Looking at Tybee Island

Breech in Fort Pulaski’s walls occurred on the angle where the south and southeast face joined, exactly as directed in Gilmore’s orders.  The fires of three batteries with four heavy caliber smoothbores and ten rifles focused upon that corner eventually tearing away the brick.  Victory was sealed by using the most effective weapons, massed to concentrate fire on the southeast corner of the fort.

Savannah 5 May 10 338

SW Corner of Fort Pulaski Today

Although repaired later, some of the battle scars remain at the breached corner.  The new brickwork (some of which I’m told dates to 1930s era projects) provides some measure of the extensive damage.

The breach serves as testament to the power of rifled artillery, in both range and destructive power.  Yet, that power pales in comparison to 20th and 21st century weapons.  But the basic principle of massing firepower at a single point to achieve the greatest effect remains today, as it did in the 1860s.

————————————————–

NOTE:  I personally have some concerns about the types of weapons noted in Gilmore’s report (which was written in October 1865, well after the event).  The calibers are likely correct.  However, the cited use of several of the newer model weapons is difficult to match with known ordnance acceptance dates.

Ten prototype 10-inch Rodman Gun were produced and received in October 1861.  The type had just entered production in early 1862, with only five proofed by March 1862.   There were five Model 1857 10-inch Columbiad, but all those were destroyed in testing.  Quantities of Model 1844 Columbiads existed (with 149 total produced).  So either Gilmore had six of those ten prototypes.  Or he mistakenly identified the Model 1844 Columbiads as Rodmans in his report.

The 13-inch Model 1861 Seacoast Mortar was in production and in use by this time, so I cannot dispute that weapon’s presence at the battle.  However, Cyrus Alger produced the first 10-inch Model 1861 Seacoast Mortars for proofing in July 1862.  A 10-inch Model 1861 Siege Mortar existed, but the earliest proofings were recorded in April 1862.  However, Cyrus Alger did produce five 10-inch mortars to the Model 1840 pattern by October 1861.  These were originally ordered under a contract for Model 1861 mortars, but evidently in the haste to receive weapons the older pattern was accepted.  Perhaps Gilmore was issued mortars from that lot, and he opted to cite them as Model 1861 due to the contract date.

About these ads