For the ability to produce terror by its mere presence piece of artillery outdid the “Swamp Angel”—the massive Parrott rifle that threatened the city of Charleston, S.C., in August 1863. From its , no single base on Morris Island, the 8-inch, 200-pounder Yankee leviathan lobbed shells nearly five miles over Charleston Harbor and into the city, scattering terrified residents. After just three dozen shots the Swamp Angel exploded, its breech shattered by the massive charge within.

The fact that the awesome gun had been put in place at all impressed Yankee and Rebel engineers alike. The murky earth of Morris Island could hardly support the weight of a man, let alone a monstrous cannon and its ponderous base. The first person charged with its installation scoffed at the idea and asked for workers “eighteen feet high.” His replacement, Colonel Edward Wellman Serrell of the 1st New York Engineers, thought otherwise. “There is no such word as impossible,” he declared. “The battery must be built at the point indicated.” And so it was—in 16 feet of mud. Serrell’s men sank a huge platform of timber into the mire, weighed it down with sandbags, capped off this foundation with heavy planking and surrounded the site with sandbag walls 15 feet thick. They then floated the cannon on a raft out to its home.

The New Yorkers’ Morris Island exploit was just one of countless near-miraculous feats performed by Civil War engineers, whose job it was to scout terrain and clear the way for the armies they served. Neither side ever had enough of them. Even after an August 1861 expansion, the U.S. Army Corps of Engineers consisted of just 49 officers and 600 enlistees. (The handful of mapmaking topographical engineers were folded into the Engineer Corps in 1863). Volunteer engineer regiments of 1,500 men each––including converted infantry units––helped. The Confederate Engineer Corps eventually organized two to three regiments of engineers, which were divided between the east and west. Competent civilian engineers were often commissioned to address a persistent shortage of officers.

Engineers on each side employed informal units of “pioneers”—soldiers skilled with the ax, spade, hammer and pick. The Union Army of the Cumberland even organized an entire brigade (aptly named the Pioneer Brigade) of such men. And while engineers planned and directed operations, these pioneers often took on the most hazardous of jobs—even as sappers and miners during hair-raising siege duty. “Officers and men,” one Federal engineer wrote, “had to learn to be engineers while the siege was going on.”

Well-equipped blue-coated engineers quickly turned puny forest paths into level corduroy roads of logs and dirt, threw up railroad trestles and spanned Southern rivers with portable pontoon (or ponton) bridges—including a 2,200-foot marvel across the James River—capable of supporting a marching army with barely a quiver.

Often on the defensive, Confederate engineers designed elaborate fortifications at Fort Donelson, Vicksburg and other waterside towns that only a manpower shortage rendered ineffective. Pioneers assembled and fronted massive earthen breastworks with endless rows of gabions, abatis and other obstacles. Well-placed Southern batteries held Union naval flotillas at bay for months. And when Maj. Gen. William T. Sherman surrounded Lt. Gen. William Hardee’s 10,000 Confederates at Savannah in 1864, Rebel engineers fashioned three pontoon bridges over the Savannah River with little more than scavenged planking and a handful of wooden “flats” from local rice fields. Hardee’s army quietly slipped out of town.

During sieges, Union and Confederate engineers dueled above and below ground while infantrymen baked in their trenches. Yankee miners and sappers tunneled to deposit explosives beneath the enemy while their counterparts in butternut dug to intercept them—and plant defensive mines of their own. The Union blasting of the Crater at Petersburg in 1864 was a masterpiece that only the subsequent bungled infantry assault obscured.

Engineers carried rifles along with their less lethal tools, although they were more likely to defend their own work parties with them than join in battle. They did occasionally come under direct fire—and take casualties. The 50th New York Engineers and similar units were sitting ducks for Rebel sharpshooters as they attempted to construct pontoon bridges across the Rappahannock River on December 11, 1862. They completed their work despite the incoming shots, however, and set the stage for the Battle of Fredericksburg.

But the engineers’ status still earned them a few barbs from soldiers like John Billings, a Massachusetts artilleryman who apparently had an opinion about most everything. “The engineers, as a whole,” he wrote, “led an enjoyable life of it in the service. Their labors were quite fatiguing while they lasted, it is true, but they were a privileged class compared with the infantry.” Regardless, without them the Civil War would have quickly stalemated—with armies glaring idly at each other across the Potomac River.

 

Originally published in the September 2006 issue of Civil War Times. To subscribe, click here