File:Lock 58 C and O From NPS.jpg

English: Lock 58 on the Cheasapeake and Ohio Canal. The NPS site says: Lock 58 is the first of the 13 composite locks. These locks differ from the other locks on the canal. Between the upper end of the lower gate pockets to the lower end of the upper gate pockets the stone walls ere moved 9 ¼° on each side, resulting in a clear dimension between lock walls of 16’-16 ½” rather that the 15’ previously adhered to. The normal clear dimension was resumed both up and down from these points. The walls were of rough-cut and rough-coursed limestone, principally dry-laid were the walls were widened and mortared in the other areas. The wider area was filled in with 5 ¼” square timbers. This wooden section of the lock was “water-proofed” at first by being “kyanized” and later with creosote. The wood timbers required frequent replacing, and around 1900 many repairs were made by stripping out the wood and pouring a cement liner with the more typical 15’ between lock walls. The wood at Lock 58 was replaced as described and the date 1909 is impressed on one of the walls. Stone walls are exposed on only the extension and wingwalls.