John D. Billings, Hardtack and Coffee: The Unwritten Story of Army Life

When the Army of the Potomac retreated from before Richmond in 1862 it crossed the lower Chickahominy on a bridge of boats and rafts 1980 feet long. This was constructed by three separate working parties, employed at the same time, one engaged at each end and one in the centre. It was the longest bridge built in the war, of which I have any knowledge, save one, and that the bridge built across the James, below Wilcox's Landing, in 1864. This latter was a remarkable achievement in ponton engineering. It was over two thousand feet long, and the channel boats were firmly anchored in thirteen fathoms of water. The engineers began it during the forenoon of June 14, and completed the task at midnight. It was built under the direction of General Benham for the passage of the wagontrains and a part of the troops, while the rest crossed in steamers and ferry-boats.

But ponton bridges were not always laid without opposition or interference from the enemy. Perhaps they made the most stubborn contest to prevent the laying of the bridges across the Rappahannock before Fredericksburg in December, 1862.

The pontoniers had partially laid one bridge before daylight, but when dawn appeared the enemy's sharpshooters, who had been posted in buildings on the opposite bank, opened so destructive a fire upon them that they were compelled to desist, and two subsequent attempts to continue the work, though desperately made, were likewise brought to naught by the deadly fire of Mississippi rifles. At last three regiments, the Seventh Michigan, and the Nineteenth and Twentieth Massachusetts, volunteered to cross the river, and drive the enemy out of cover, which they did most gallantly, though not without considerable loss. They crossed the river in ponton boats, charged up the steep bank opposite, drove out, or captured the Rebels holding the buildings, and in a short time the first ponton bridge was completed. Others were laid near by soon after.