Pontoon Bridges – Simply Ingenious

We are approaching the sesquicentennial of the Battle of Fredericksburg (and a series of Enfilading Lines posts about it!). And whenever I think of this battle, my mind takes me to a consideration of what I view as fascinating pieces of engineering – the pontoon bridge.

Example of a Pontoon Bridge – at Appotommax

Perhaps the most famous of these are the bridges built over the Rappahannock River at Fredericksburg. This was done under the sniping fire of Barksdale’s Confederates … who were themselves under fire from Union artillery. It was a difficult enough job to build a bridge floating on the water current, let alone to do it under fire. This is the first such encounter in American military history.

Pontoon boats were anchored parallel to each other with beams connecting them across the gunwales … followed by planks at a 90-degree angle to the beams. For a great article that describes not only the construction of pontoon bridges (and specifically those at Fredericksburg), but also gives a history of such engineering, click HERE.

Regarding the construction of the pontoon bridges at Fredericksburg, here is an account from his “Personal Recollections of the Civil War” by John Gibbon:

Early on the morning of the 11^th our Corps (1^st) started. A dense fog covered the whole face of the country and for a time concealed our movements but as it became lighter the sound of a cannon boomed out and the conflict began. As we neared the river, the sharp rattle of musketry could be heard up at the town where attempts were being made to throw bridges across. Down below where we were to cross, the opposition was but slight and only from skirmishers, the main line of the enemy being back on the hills beyond the broad flat which extended from the hills to the river. The skirmishers were driven away and the work of building our bridges and occupying the other bank of the river went on.

A.P. Smith, the author of The History of the 76^th New York shares another account:

Early on the morning of the eleventh, the pontoons were brought down to the river’s brink and laid, one bridge by the Fifteenth New York Engineers, and the other by the United States Engineers, while the cannon stood, heavily shotted, upon commanding eminences, threatening destruction to the enemy in case he attempted to interfere with the workmen.

City of Fredericksburg

No duty requires more real courage than the laying of bridges, in the face of the foe. The excitements of the field prepare the soldier for the severest charge; but the engineers, without the stimulus of excitement, must march down to the stream, though the rebel pickets and sharpshooters threaten on the other shore. The bridges were, however, laid, and today crossed in the face of the enemy.

The seventy-sixth was ordered to guard the bridge to prevent any retreat of stragglers or others, even at the point of the bayonet, as the General said, because this Regiment could be depended upon in any emergency.

After the experience of the past few months, the glory of being shot at was not very highly prized. The men rather considered it good fortune when obedience to orders required their presence at a point not particularly exposed; and though in all the record of the Seventy-sixth, no instance can be found where, as a regiment, it sought to avoid the performance of its whole duty, yet the truth impels us to do justice to that common instinct which there, as elsewhere, preferred safety to danger.

Early in the morning, December thirteenth, firing commenced all along the lines, and it soon became apparent that a severe engagement was about to take place. The Seventy-sixth was congratulating itself upon its good fortune in escaping a participation in the dangers of the fight, when, about nine o’clock, orders were received to join the Division moving to the front.

The general he is talking about is Abner Doubleday – the 76^th being part of his division. They occupied the extreme left of the Union line.