The Union Siege of Vicksburg
There are a lot of books on the campaign of Vicksburg, and the battles around Vicksburg. I even know of one that discusses the geology of the region and its impact on the campaign. This is the first that concentrates on the Siege as a siege, rather than a battle.
The purpose of a formal siege as understood by a trained 19th century military man, is to get the army close enough to the works to batter down the walls and works, provide a sheltered path for troops to launch an assault that will carry the fort. In standard military rules, the defenders would then give up and surrender at this point and save the risk of an assault.
In my readings as a young adult, I had always gotten the impression that the defenders gave up a little early to get terms on the 4th of July. When I visited the place, though, I was impressed to see an approach trench on the north of the town moving straight up a very steep hill to nearly the top, marked by a sign stating that this was the Union position on July 4. They were close indeed!
The picture below is that same approach trench – you can see the scar going up toward the Confederate line at the top of the hill..
The Union Army really had not intended to besiege the place, and so did not have any prepared tools and guns ready. Also, the Western army had few trained engineers, who normally direct almost every operation – one count says there were four. And this position was miles and miles across. But one thing Union armies, especially the Western ones could do was improvise.
The first method used to get engineers was to dragoon any civilian engineer in the ranks and put them to work directing operations. Also, West Point officers had some engineering training. One commissary officer, somewhat overweight complained that he could best be used as a sap roller! A sap roller was a round mass of branches and reeds used to create a bullet-resistant shield in front of a trench heading forward to a position.
So while at first the knowledge was concentrated in a few, circumstances required training to be spread down to the rank and file. While this caused some initial problems, later on the engineers found that it made more work possible since they could delegate to the entire army than to just a few engineering troops available. And the troops were willing enough once they got the idea. There was an incident where General William T. Sherman was riding by and saw a detail of about 100 men idle. Asking what was up, the officer in charge showed him an order to make 50 gabions and 50 fascines. The officer then said the unit was only a year old and had never been in siege work before. Sherman got down from his horse, asked for an axe and personally started cutting down small trees and driving them into the earth to make a gabion. This is like a large bottomless woven basket, which could be carried to a position, hammered into the ground and filled with earth to make a shotproof wall quickly. Sherman then cut grapevines and began personally weaving them to form the walls. After this was well begun, the began binding straight cane stems into bundles – fascines. These have a number of uses – bracing dirt walls, or tossing in a trench to fill it in quickly in an attack. By the time Sherman left, those men knew how to make fascines and gabions, if not the French names.
The author’s theory is that this is the last classic siege – the enemy surrounded, parallel trenches set up and approach trenches set up close for a final assault. It was modified somewhat for the changes in military technology and the terrain. Two traditional mines were dug and a part of the defenses blown up. Other sieges in the Civil War, like Petersburg and Atlanta, did not surround the city at any time, or create approach trenches.
This book puts a new, complementary spin on this important campaign.