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  • Writer's pictureGordon Thorsby

The Mortar Flotilla For New Orleans

by Gordon Thorsby

New Orleans was the largest city in the South at the outbreak of the Civil War. It was larger than Richmond in 1861 and it was much larger than Atlanta. It was the greatest port for the South with vast ship traffic from all along the Mississippi North and South and for exports and imports to elsewhere in the world. Despite its importance to the South, it easily fell to three squadrons of Union naval ships on April 25- May 1, 1862; less than one year into the Civil War. How did it happen so quickly?

The full explanation would take much more than explained here. On the Southern side of the equation, several Confederate ships that had been built in New Orleans that were intended for New Orleans were sent upriver for defense on the Mississippi and were not available for the defense of the port. Several thousands soldiers assembled for the city’s defense were sent to add to the infantry that would advance into Tennessee. The port’s defenses were steadily being stripped of its ability to hold off a Union effort. One might question what Richmond was thinking.

On the Northern side of things, David Farragut and David Dixon Porter, two important individuals in the naval portion of the war (also foster brothers) were primary performers in the effort to take the town. There was also Benjamin Butler with the infantry but his effort was minor. There were various gunboats but the key player naval craft were Porter’s mortar boats.

The mortar flotilla were wooden crafts and lightly rigged. They were meant to pound fortifications into submission. They were not meant to move and maneuver. Porter placed them to get in range to bombard Forts Jackson and St. Phillip and let their range and weight speak for themselves. Each craft weighed several tons. The mortars themselves were behemoths. Each craft had a 13” mortar on them that weighed 17 tons a mortar craft had a forty man crew. Each round for the mortar were of iron with eleven pounds of powder inside and had a service charge that weighed twenty pounds. The range of a shot was over 3000 yards that would take 25 seconds to hit its targets but they were known to go to 4000 yards. With mortar, rounds and men manning the mortar, these were heavily laden craft. It is reported that Porter’s men referred to the crafts as “chowder pots.”

The mortars proved themselves very accurate, especially as they only had to hit the permanent forts next to the river. The fuses were not good and the paintings one often sees of bursts above their targets was the result a many shells' results. The problem was resolved quickly. Fuses were left long and the result were the shells buried themselves 18-20 feet deep into the ground at their impact. And when the shells went off? Witnesses reported each was like a mini-earthquake, lifting the ground before returning to its place. It would be very disturbing to defenders in the fort. Did the mortar squadrons perform as they were designed? They did not meet expectations, but their power were a problem that Confederate defenders had to address.

We discuss the brutal battle that happened at Shiloh on April 6-7. We do not discuss New Orleans that happened in the same timeframe. New Orleans is almost a footnote in comparison yet the two engagements occurred within three weeks of each other. Shiloh was to portend what the Civil War would become. The impact of New Orleans’ capture was significant to how Western Theater War would develop for the rest of the war. The South would not recover from its loss.

Reference: Bielski, Mark F., A Mortal Blow for the Confederacy, Savas Beatie, 2021.

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Rod Haynes
Rod Haynes
Oct 28, 2021

Excellent article. I would also mentioned poor command and control between the various Rebel navies at the scene, the lack of preparedness / poor mobility of the unfinished Confederate warships to defend the two forts and New Orleans, and the meticulous tactical planning of Farragut, who made sure every CO of a ship knew exactly what was expected of him. I think Farragut didn’t believe the mortars were pivotal at that battle. I believe it was the combined firepower of Farragut‘s steam fleet and the swift mobility of that fleet in getting past the Rebel fortifications that won the battle of New Orleans. I do think the Confederate naval leaders believed the attack on the city would come from t…

Gordon Thorsby
Gordon Thorsby
Feb 26
Replying to

Thank you for your careful thought and feedback. Much appreciated.

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