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 C&O Canal Association

Civil War

A Case of Lockjaw

by  Dave Johnson

In the first winter of the war, General George B. McClellan was under pressure to reopen the B&O Railroad to the west of Harpers Ferry and to secure the lower Shenandoah Valley.  To do this, he planned to post a strong garrison between Harpers Ferry and Winchester.  To support that force, it was necessary to build a bridge across the Potomac River at Harpers Ferry that could be used until the railroad bridge, burnt by the rebels the previous year, could be repaired.

In late February 1862, the army engineers quickly laid a light bateau (pontoon) bridge over the river, which allowed infantry to cross.  It was next planned to build a heavier bridge for artillery, cavalry and supply wagons.  This would use canal boats moored abreast as platforms to support the bridge deck.  A number of boats were acquired and brought up the canal to the Shenandoah River lock, and all seemed in readiness to construct the wagon bridge.  General McClellan related what happened next in his subsequent report to the War Department:1

“Next morning the attempt was made to pass the canal boats through the lift-lock, in order to commence at once the construction of a permanent bridge.  It was then found for the first time that the lock was too small to permit the passage of the boats, it having been built for a class of boats running on the Shenandoah canal, and too narrow by some four to six inches for the canal boats.  The lift-locks, above and below are all large enough for the ordinary boats.  I had seen them at Edwards Ferry thus used.  It had always been represented to the engineers by the railroad employees, and others, that the lock was large enough, and, the difference being too small to be detected by the eye, no one had thought of measuring it, or suspecting any difficulty.  I thus suddenly found myself unable to build the permanent bridge.” 

President Lincoln, already disenchanted with his general, was not amused.  He vented his anger to McClellan’s chief of staff, General Marcy.  “I am no engineer,” he stormed, “but . . . if  I wished to know whether a boat would go through a hole or a lock, common sense would teach me to go and measure it.”3 

A popular joke in Washington that winter, recorded by the dour Treasury Secretary, Salmon P. Chase, was that McClellan’s Winchester expedition died of lockjaw.4

In the end, this incident was more humorous than disastrous.  The railroad bridge was eventually repaired, the Union troops occupied Winchester, and McClellan led his maligned and ill-fated army to the real disaster known as the Peninsula Campaign.

It is hard to believe that the C&O Canal Company, so grand in the design and construction of its structures, would have built as potentially important a work as the river lock opposite Harpers Ferry a half-foot narrower than the standard width for all other locks.  A more logical explanation may be that the walls of the lock chamber had pressed inwardly (a common occurrence), and that, as the lock had been little used during the nearly thirty years since it was built, it had not been properly maintained.5

It was originally planned to build Dam #3 downstream of the Shenandoah Falls, below Lock 35, to form a pool for boats to cross to Harpers Ferry as well as to be the feeder to the canal.  The government objected, because the pool would raise the river level dangerously close to the arsenal.  Construction of the dam was abandoned and the Government Dam at the head of Harpers Ferry Falls, near Lock 33, was used for the feeder.  The original inlet lock was converted to an outlet to provide access to the Shenandoah.  However, the B&O Railroad blocked use of their bridge to carry the towing path across the river, and the outlet lock fell into disrepair.  When the canal was rebuilt after the 1889 flood, the Shenandoah outlet lock was filled in.6


1. Report of General George B. McClellan, (Washington:  Government Printing Office, 1854), 52.

2.  Although Gen. McClellan uses the term “lift-lock”, he is referring to the outlet (river) locks.

3.  Catton, Bruce, Terrible Swift Sword, (Garden City, N.Y.: Doubleday & Co.,  1963),  194-195 ; also, Sears, Stephen W., George B. McClellan, the Young Napoleon, (New York: Ticknor & Fields, 1988), 157-158.

4.  Leech, Margeret, Reveille in Washington,  (New York: Harper Brothers, 1941), 129.

5.  For more information on the pressing in of lock walls, see Karen Gray’s article “Those Incredible Shrinking Locks,” Along the Towpath, Vol. XXXII, No. 4 (Dec. 2000), pp. 18-19.

6.  Davies, William E., The Geology and Engineering of the Chesapeake & Ohio Canal, (Glen Echo, Md.:  C&O Canal Association, 1999),  196-197.

(This article first appeared in the June 2000 issue of Along the Towpath, the newsletter of the C&O Canal Association, and was reprinted in the September 2009 issue.)

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