HISTORIC STRUCTURES REPORT

ARCHITECTURAL DATA SECTION

SURVEY REPORT FOR

THE LOCK #66 COMPLEX

Located North of Paw Paw Tunnel

Chesapeake and Ohio Canal

Prepared by

Archie W. Franzen

Architect

December 1967

For

United States Department of the Interior

National Park Service

Office of Archeology and Historic Preservation
ii

CONTENTS

I. EXISTING CONDITIONS 1

II. RECOMMENDATIONS 3

III. ESTIMATE FOR RESTORATION AND REPAIRS 3

IV ILLUSTRATIONS 4

Illustration 1: Historic American Buildings Survey drawings of Lock 66 4

Illustration 2: Perspective drawing of the entire complex 5

Illustration 3: Lock #66 from the towpath at the upstream end 6

Illustration 4: Downstream view showing size and extent of wing walls 7

Illustration 5: Looking upstream from within the lock 8

Illustration 6: View of wood lock sheathing at Lock #64-2/3 9

Illustration 7: square washers on the rods that held the vertical studs in place 10

Illustration 8: Close-up of the stonework of the lock sidewalls 11

Illustration 9: Near view of creosote dip tank 12
1

SURVEY REPORT FOR LOCK #66 COMPLEX

Located North of Paw Paw Tunnel

I. EXISTING CONDITIONS

The construction of the seven locks, #59, #60, #61, #62, #63-1/3, #64-2/3 and #66, was placed 

under one contract and work was started between May 1838 and December 1939. Because of 

various vicissitudes, outlined in the Physical History of the Canal1, construction was not completed until sometime between 1848 and 1850.

The primary construction problem, encountered in building these locks, was a lack of good 

building stone in the area. Large substantial stones, normally employed in lock construction, 

could not be cut from the material available and as a consequence small stones were used. The 

locking through of heavily laden boats subjected the lock walls to considerable abuse that small 

friable stone could not withstand. As a consequence, the lock walls between the gates were lined 

with wood for protection.

This was accomplished by fastening 5-1/4” square vertical studs to the stone surface at 30” intervals. The stud fastenings were four-foot long, one-inch round steel rods driven into the masonry 

joints and threaded at the exposed end to receive square nuts. There were two rods per stud. The 

studs ran from a 6” wide by 3-1/2” deep sill at the bottom to the underside of the now missing 

overhanging cap or coping stones. A layer of horizontal planking was nailed over the studs and 

another layer of vertical planking was applied over the horizontal planking for strength.

Only the bolts and a stud or two survive at Lock #66, but a good portion of the planking exists in 

place, a tenth of a mile downstream, at Lock #64-2/3. This planking is in a dilapidated condition.

The distance between the masonry of the sidewalls of Lock #66 is 16'-8". The average width of 

the majority of the locks of the canal is 15'-0". This suggests that lining these particular locks 

was planned for prior to their construction. The addition of the lining would still result in a nominal 15'-0" width.

The timber of the lock facings was treated to preserve it and this treatment was referred to in the 

canal company reports as “Kyanized”.

Because of the configuration of the gate pockets and headwalls, it would have been impractical 

to attempt to line their masonry surfaces with wood. These surfaces had cement applied to protect them from abrasion and strain. It is not certain if the cement was applied originally or not.

The date 1910 has been marked in the cement on some of the surfaces.

Remnants of the wood gates at both the upstream and the downstream ends of the lock still remain. Their bottoms are lodged in silt and for this reason it cannot be determined, at this time, if 

 

1 Miele, John R., The Chesapeake and Ohio Canal, A Physical History, dated Jan. 2, 1964, pp. 23 – 25.
Survey Report for Lock 66 Complex

2

it would be possible to rehabilitate them or not. Some portions of all of the gates have sustained 

severe damage due to rotting. Most of the gate hardware is missing.

Lock #66 had a by-pass flume like other locks in the system. However, at the upstream end, there 

was a concrete weir gate arrangement parallel with a spillway. Another spillway was located at 

the downstream end of the flume. (See illustration).

Because of its remoteness, it is difficult to understand why a carpenter’s shop would be located 

at the site of this lock. Former employees of the canal company say that lock gates were fabricated and repaired here. The structure that housed the shop has been a shambles for a good many 

years and has now melted down to ground level. It measured 20'-2" in width by 40'-4" in length 

with a height of 11'-0" from grade to the top of the eaves plate. The arrangement of windows and 

doors is only partially known. Its framework was of post and girt construction with board and 

batten siding. The roof was pitched and was probably covered with shingles originally. There 

was a 6’-0” open area under the interior plank floor. The post and girt system was substantial and 

indicated that block and falls were used to manipulate the heavy gate timbers during assembly.

A creosote dip tank was located at the north end of the shop building. It was made of 3/16” thick 

steel plate and had a diameter of 28-1/4" outside. It was approximately six feet high and was 

shielded from the wood building by a concrete wall on two sides. The top of it was roughly level 

with the ground level between the lock and building.

The creosote treatment was apparently a non-pressure process with the timber heated and allowed to cool in the tank. To accomplish this the tank is supported at its base by a concrete slab 

and under which there is a space to build a fire for heating the tank. Some form of boom or Aframe must have been used to lower the ends of the heavy timbers into the tank, but such an arrangement has vanished.

There are a number of wing walls and retaining walls within the complex. Erosion has dispatched portions of them. The lock walls have remained reasonably plumb indicating that they 

are founded on firm and solid material.
Survey Report for Lock 66 Complex

3

II. RECOMMENDATIONS

The lock should be cleaned of silt and trash to below the mud sill level of the downstream gate.

The masonry sidewalls should have any loose stone reset and any missing stone replaced, including the missing capstones. The corroded ends of the steel bolts that fastened the wood lining 

should be burned off with new threaded ends welded in their place. This will make it possible to 

replace the wood lining.

If after uncovering the existing gates it is found that they warrant refurbishing this should be 

done. Otherwise, new gates should be fabricated. It is felt that with development of visitor accommodations planned for the area at the south end of the tunnel that this lock should be made 

operable. This would give the visitor a rest stop feature to view after hiking through the tunnel.

The contiguous wing walls, retaining walls, weir and spillways should be repaired to accommodate the re-watering of the canal through the tunnel.

So little is known of the operation of the carpenter’s shop, it might be best to remove the existing 

fabric remains and stabilize the masonry foundation rather than reconstruct it.

If the shop building were reconstructed, some means would have to be provided to cross the rewatered canal to reach it. No evidence has been found to indicate that there was any kind of 

bridge at this location, and it may have been that the men working in the carpenter’s shop 

crossed over the top of the lock gates.

III. ESTIMATE FOR RESTORATION AND REPAIRS

1. Masonry Work (Lock walls, wing walls, flume wall, spillways and weir) $11,825.00

2. Wood Lock Lining (Including anchor bolt repair) $8,435.00

3. Lock Gates (Estimated if totally replaced) $13,875.00

4. Clean-Up, Scaffolding, Equipment $1,000

5. Raze Carpenter’s Shop and Stabilize Foundation $2,500

Total for construction $37,635.00
Survey Report for Lock 66 Complex

4

Illustration I: The following drawings are available (on-line) in two higher resolutions from Historic American Building Survey, Chesapeake & Ohio Canal, Lift Lock 66
Survey Report for Lock 66 Complex

5

Illustration 2: This perspective was constructed from a viewpoint to show the entire complex.

The depression between the lock and flume and behind the wall connecting the lock and weir 

was probably caused by erosion resulting from a break in the flume wall. It was shown, however, 

as it might have been a timber soaking pond. The height of the creosote tank has been exaggerated to show its location. The spillway in the foreground had notches at its ends to receive timbers.

Why this was done immediately adjacent to the weir is not understood. The object of the flume 

was to pass surplus water on to lower levels along the canal using the weirs to maintain a proper 

level of water in the level above. Sketch: A. W. Franzen, September 1967.
Survey Report for Lock 66 Complex

6

Illustration 3: View of Lock #66 from the towpath at the upstream end. The character of the 

stone can be seen and how it was reinforced with concrete in the gate pockets. What is left of the 

carpenter’s shop can be seen in the background. The lock is 99’-6” long between gates and 16’-

8” wide between the masonry of the sidewalls. Photo: A. W. Franzen, August 1967
Survey Report for Lock 66 Complex

7

Illustration 4: View of lock from downstream showing size and extent of wing walls. To the right 

can be seen the top of the creosote dip tank. For scale, it is eighteen feet from the top of the lock 

to the water in the foreground. Photo: A. W. Franzen, August 1967
Survey Report for Lock 66 Complex

8

Illustration 5: Looking upstream from within the lock. This view gives a good idea of the condition of the lock gates and their size. They are approximately fifteen feet high. Note how silt has 

amassed at the bottom of the gates. Photo: A. W. Franzen, August 1967
Survey Report for Lock 66 Complex

9

Illustration 6: View of wood lock sheathing at Lock #64-2/3. Similar construction was employed 

at Lock #66. The missing capstones would have overhung the wood construction to protect it and 

prevent trash from falling down in the space between studs. Photo: A. W. Franzen, August 1967
Survey Report for Lock 66 Complex

10

Illustration 7: This close-up shows the square washers on the rods that held the vertical studs in 

place. Many of the nails appearing in this view are wire nails and suggest that the sheathing had 

to be replaced in recent years. Taken at Lock #64-2/3. Photo: A. W. Franzen, August 1967
Survey Report for Lock 66 Complex

11

Illustration 8: Close-up of the stonework of the lock sidewalls. Two of the stud fastening rods 

appear as they protrude from the stonework. It is obvious from their condition that the rods will 

have to have their ends cut and replaced. The rods are four feet long and would be next to impossible to pull loose. The rods are roughly thirty inches apart and give an indication of the size of 

the stone and how it was laid up. Photo: A. W. Franzen, August 1967
Survey Report for Lock 66 Complex

12

Illustration 9: Near view of creosote dip tank. Heat was applied beneath the tank to accelerate the 

absorption of the creosote. The concrete dike at the base of the tank kept spillage from reaching 

the fire. Photo: Jack Boucher, December 1960