Engineers in Union blue and Confederate gray played a prominent role in the Vicksburg campaigns of 1862-1863. Although their contributions have largely gone unnoticed in published works on the campaign, the stories of these men and the fatigue parties that toiled under their supervision are worthy of note and will be detailed in this series of articles.
Part 21: Plotting Logan’s Approach
Union captain Andrew Hickenlooper of the XVII Corps was another engineer who took advantage of the truce on May 25 to examine the terrain in his front.
Born in 1837, the Hudson County, Ohio, native was compelled to leave school at the age of 10 to help support his struggling family. He first worked as a messenger at the local newspaper; then, at the age of 16, Hickenlooper became a rodman working under Cincinnati’s city civil engineer, Alfred Gilbert, who was then managing a topographical survey of the Queen City. The young man applied his boundless energy and received additional tutoring from the project’s head topographical engineer, J. T. Hogan. In short order he rose to became a draftsman and surveyor in his own right.
Although Gilbert was ousted as a result of politics in 1855 - and Hickenlooper with him - their relationship went on to greater success. The two formed the firm of Gilbert and Hickenlooper, Surveyors and Civil Engineers, which quickly became a lucrative venture.
With the outbreak of hostilities in 1861, Hickenlooper obtained approval From Governor William Dennison to form a battery, which became the Fifth Ohio Independent Battery of Light Artillery. Better known as Hickenlooper’s Cincinnati Battery, the unit served with distinction at Shiloh and Corinth in 1862, and the young captain received praise for his daring and bravery. Due to the shortage of experienced engineers, however, Hickenlooper was appointed chief engineer of the XVII Corps led by Maj. Gen. James McPherson, and served in that capacity throughout the Vicksburg campaign.
On that hot day in May, as he wandered out between the lines, Hickenlooper focused his attention on the Jackson Road, which entry point was guarded by two powerful bastions, Third Louisiana Redan on the north, and Great Redoubt on the south. (A redan is a triangular-shaped fortification, the apex of which faces the enemy. A redoubt is a large rectangular-shaped fort, and Great Redoubt was the largest, most-formidable of those that protected Vicksburg.)
With a surveyor’s keen appreciation for topography, the corps’ engineer noted that the Third Louisiana Redan, which jutted out from the Confederate line, dominated the adjacent earthworks. He realized if the Federals gained possession of that fort, the defenses on lower ground to either side would be untenable. Unlike Lockett, the Confederate engineer, Hickenlooper was able to make a careful analysis of the terrain without being distracted. Once the truce ended he returned to his tent and prepared a map on which he plotted the best route of approach to the redan.
Early the next morning, Maj. Gen. John A. Logan, commander of the division positioned astride Jackson Road, detailed a force of 300 men to report to Captain Hickenlooper for the purpose of sinking an approach. Working in shifts of 100 men each, the sappers, as they were called, broke ground south of Jackson Road approximately 150 feet southeast of the Shirley House (the only surviving wartime structure on the grounds of Vicksburg National Military Park) and 400 yards east of their objective. Known as Logan’s Approach, the sap (or trench) was about seven feet deep and eight feet wide. Thus, it was deep enough to allow the average man of that time to stand without exposing himself to enemy sharpshooters, and wide enough to permit passage of a column of troops four abreast. It also enabled the passage of wagons and artillery.
Despite the oppressive heat, the sappers working under Hickenlooper’s supervision made rapid progress and, by the beginning of June, were well on their way toward the redan.