The breakwater of the city of Burlington, Vermont, is a historically significant structure. Work on the breakwater began in 1836, when congress authorized the construction of the first 1,000 feet. It was extended numerous times in the 19th Century, and presently totals 4,175 feet in length. The construction of the breakwater correlates with the development of the City of Burlington and its maritime commercial interests. The structure is considered a significant example of 19th century timber crib construction. Destructive action of waves and ice over the decades has resulted in the need for periodic maintenance and reconstruction since the breakwater's completion, with the last major repair occurring in 2002. Over time, the structure has deteriorated significantly, particularly on the ends, with portions of the wooden cribbing collapsing and displacement of the granite capstones occurring in numerous places. Recent repair work undertaken by the U.S. Army Corps of Engineers, New York District (Corps), will help prevent further deterioration of the breakwater but this construction has altered its historic fabric. As a federal agency, the Corps has certain responsibilities with regard to the protection and preservation of historic resources, and as such, cultural resources investigations were undertaken prior to repair. The work included historic research, an underwater survey of the structure to document historic construction techniques, the production of reports, installation a sign about the history of the breakwater for the Lake Champlain waterfront and production of this webpage. The Burlington Breakwater was listed on the National Register of Historic Places in June 2003.

Historical Background

On February 26, 1834, Lewis Cass, Secretary of War, presented to the 23 rd Congress estimates prepared by the Topographical Bureau for the improvement of Burlington, Port Kent, and Plattsburgh Bays on Lake Champlain (Figure 1). The estimate for the 1,000-foot Burlington breakwater was $28,727.18; the 675-foot Port Kent breakwater was $43,876.27; and the 1,000-foot Plattsburgh breakwater was 24, 003.16. Three years later, construction began in Burlington and Plattsburgh, but the Port Kent breakwater was stricken from Harbor Bill despite intense lobbying from entrepreneurs in Port Kent. Ultimately, Lake Champlain would have five federal breakwaters: Burlington; Plattsburgh; Swanton, Vermont; Rouses Point, New York; and Gordon Landing, Grande Isle, Vermont. The first “V”-shaped section of the Burlington breakwater was completed in 1854 (Figure 2).

Figure 1: Map of Lake Champlain

Figure 2: Photo of breakwater under construction circa 1854 Photo courtesy of UVM Bailey
Howe Library Special Collections

Commerce on Burlington's Waterfront and the Construction of the Breakwater

The breakwater expanded to coincide with commercial growth at Burlington's waterfront. Lake Champlain was a major commercial artery, and Burlington a primary port. Maritime commerce was bolstered by several specific events. The completion of the 46-mile Champlain Canal in 1823 opened the lake to New York markets. In 1843, the completion of the 12-mile Chambly Canal in Quebec around the Richelieu River rapids reaped additional economic benefits, especially after the signing of U.S.-Canada trade agreements in the mid-1850's that permitted American entrepreneurs to import large quantities of cheap Canadian timber. At the same time tourism via the lake's steamers reached its heyday. At the height of the boom 1,021 steamers, ships, and canal boats were registered in the Champlain district, and in the vintage year of 1873, when it was the third largest lumber port of the United States, Burlington received 170 million board feet. With all of this maritime activity, wharf construction extended north and south along the waterfront, and this expansion necessitated the expansion of the breakwater (Figure 3).

On the original section, the cribbing was constructed of round and squared hemlock, with the upper seven feet built of white pine. At the time, white pine cost twice as much as hemlock. Specifications stated that the wood was to be less than one foot square. For the most part, cribs were approximately 100 feet long by 50 feet wide at the bottom, and 35 feet wide at the surface of the water. The breakwater rose an additional height of eight feet above the low water mark using the same timber and stone construction as below the surface of the water.

In 1867 the second wave of construction happened on the breakwater. The Board of Engineers adopted plans to extend the breakwater to the north approximately 1,500 feet using cribs ranging form approximately 80 to 100 feet long by 30 feet wide. As before, the plans called for the lower 20 feet of the cribbing to be of hemlock, with the upper portion including superstructure to be built of pine timbers, with stone ballasts.

Figure 3: Burlington waterfront circa 1875. Photo courtesy of UVM Bailey Howe Library, Special Collections Burlington Collection 1-22.12

Repairs and Expansion

Throughout the late 1880s and 1890s, appropriations, as they became available, were directed to repairing the aging superstructure and extending the line of protection northward and southward to keep pace with the expanding line of docks and wharves.

In 1890 an all-stone superstructure was tested on the 360-foot new construction north of the 200-foot opening. Reportedly the method met all expectations and provided a very cheap and durable breakwater resulting in the systematic replacement of the aging timber superstructure by stone. The armor and capstones were set in place from a derrick scow and partly from a wall derrick running on a track laid on the crown of the completed work. By 1896, the breakwater was 4,200 feet in length.

In 1908, it was discovered that 1,165 feet of the substructure on the lake face was unstable. The recommendation was made to build a rubble mound extending the full height of the substructure cribs, and in 1911 the repair was made. Rubble facing eventually stretched the full length and height of the subsurface lake face of the breakwater, leaving the timber cribs visible (below water) only on the harbor side.

In 1901, another method of superstructure design was tested when a 140-foot section of the stone and timber superstructure was removed and replaced with a concrete superstructure. The concrete proved to not wear well, and in 1941 stone was again the material of choice. In 1961, new granite armor stone was laid. The gray appearance of the above-water breakwater is Barre granite, dating from that repair.

In 2001, the Corps repaired the southern and northern ends of the southern section breakwater and the northern end of the northern piece. The repair work included removing limited portions of damaged cribbing, applying a layer of core stone, and armoring the core stones with capstones. In the failing sections, the vertical timber crib, then exposed along most of the harbor side of the structure, was covered with sloping stone similar to that now found on the lake side of the structure. In 2002, the Corps repaired several additional areas in a manner similar to the work undertaken the previous year.

Archaeological Investigations

Two investigations of the breakwater were undertaken in advance of the two episodes of repair work. The first of these took place in July 2000 when a team of maritime archaeologists from Panamerican Consultants, Inc., of Memphis, Tenn., recorded the sections of the historic breakwater that would be affected by the repairs proposed at that time. Additional work was undertaken in the autumn of 2001. This additional work examined not only portions of the breakwater then proposed for repair but looked at the structure as a whole to document the various periods of construction and record unique construction techniques. All work was coordinated with the Vermont Division for Historic Preservation.

Using surface-supplied air, the divers logged over 18 hours of bottom time during the initial survey. They took three hours of video and numerous rolls of color and black and white film (Figure 4). Annotated drawings were made of various aspects of the breakwater (Figure 5). The record concentrated on details of the structure that would increase our knowledge of 19th century timber crib construction. This translated primarily to construction techniques, including corner joints, but also of interest was an area of damage that is supposed to have resulted from a storm in 1876.

Figure 4: A diver from PCI recording portions of the breakwater

Figure 5: Detailed drawing of a section of cribbing.

Results of the initial investigation revealed two things. First, there were three types of cribbing present in the project area (detailed in the section "Construction Techniques" below). Second, and more interesting, the area of storm damage, presumed to have occurred in 1876, may in fact be more recent. The crib, which is damaged is of a later type than the rest of the breakwater, and may have been added after the 1876 storm, in which case the damage could not have been caused by the storm. This determination is not ironclad, however, and research is continuing.

The second study took place from October 24 to November 7, 2001, when Panamerican Consultants, Inc., returned to the breakwater to complete another dive. During this investigation, the entire harbor side of the breakwater was examined, while roughly 1,000 feet of the 4,200-foot structure were recorded in detail. The investigations focused on those features that were diagnostic with regard to the construction history of the breakwater. They revealed that the breakwater structure displays evidence of possible historic damage, historic repairs, and modern damage consistent with its high-energy location. In addition, Fifty-three caissons were encountered; these were divided into 10 types based on timber and joint types used in construction (see “Construction Techniques, below). The numerous variations of wooden crib construction coincided perfectly with the various construction episodes of the structure.

The second investigation sought to collect enough data to allow preparation of plan and profile views of the historic structure, and photographic and video views, as well as an understanding of construction methods and techniques used throughout the structure's 54-year construction history.

Construction Techniques

2000 Investigations

The main method of construction of the breakwater was the use of a wooden crib, on a stone or rubble base, with a stone cap. The basic construction of the cribbing falls into two types: open cell crib and solid crib (Figures 6 and 7). Both types consist of hewn timbers, one foot square, built up one on top of the other in alternating rows of headers (width spanning timbers) and stretchers (length spanning timbers). The timbers were notched together, log cabin style, to form a boxed frame. The difference between the two types is the tightness of the construction: in the open cell crib, one foot spaces were left between rows of headers and stretchers, while in the solid crib, there are no spaces between timbers.

Figure 6 (left): Open celled crib type wharf construction (source: Hobley 1981:6);
Figure 7 (right): Solid crib type wharf construction (source: Heintzelman 1985:91)

Historical documents reveal several crib styles used in the project areas. Figures 8 - 10 show these styles. The northern-most end of the south breakwater, added between 1874 and 1883, employs a square crib placed on a sloping rubble base (Figure 8). The southern-most end of the south breakwater, constructed in the late 1880s, employed a crib with a sloping side placed on a rubble base, like that in Figure 9. Both crib types were 80-120 feet in length. At some point, additional 40-foot cribs of the type shown in Figure 10 were added to the ends of the breakwater.

Figure 8 (left); Figure 9 (center); Figure 10 (right)

Archaeological investigations noted a number of differences present in the construction of the individual cribs. Basically, three variations were noted, as shown in Figures 11 - 13. The main construction technique used in the project areas consisted of one foot timbers with a protruding lap joint at the corners, with the courses held together by iron pins (Figure 11). Interior headers were fastened to the stretchers via a housed saddle notch (Figure 12). Other cribs were constructed using the housed saddle notch on the corners and the interior headers, and fastening them to the other courses with iron pins
(Figure 12). The repair cribs added to the extreme ends of the breakwater in 1906 were constructed of one-foot-square timbers, fastened together at the corners using a lapped notch (Figure 13), while the interior headers were fastened to the stretchers using a housed saddle notch (Figure 12). The individual courses are fastened to each other with a vertical iron pin running the entire height of the structure.

Figure 11 (left): Protruding lap joint;

Figure 12 (center): Housed saddle notch;

Figure 13 (right): Lapped notch.

CAISSONS TYPES (see Figure 14 for locations)

TYPE 1

This type is the oldest in the breakwater structure and corresponds with Phase I construction as detailed in the historical background (1836-1854). Individual caissons, numbering 12 in sections 1 and 2, each measure 100 feet in length. Historical documents indicate an open crib type of construction, with a width of 50 feet at the base and 35 feet at the top, and a vertical face on the lakeside. Timbers used for construction were round, and basically consisted of raw logs with the branches and bark stripped off. Diameters varied from 10 inches to 18 inches, and were fastened using wooden trunnels. Joints were of the pin-only type (Figures 17 and 18).

TYPE 2A

This type corresponds with the next oldest construction episode (and the oldest of Phase II), occurring in 1867-1872. Individual caissons, numbering eight in Section 3 and one in Section 5, measure 66—110 feet in length, with most being 80 feet in length. Historical documents indicate a width of 30 feet. Corners were jointed using a modified saddle notch, while the interior joints consisted of a regular saddle notch. Individual timbers were spliced together using standard butt joints, either staggered or random
(Figures 19 and 20).

TYPE 2B

This type corresponds with construction occurring 1871-1874, during Phase II. Individual caissons, numbering seven in section 4, measure between 30 and 110 feet, with most falling in the 90—110 foot range. Historical documents indicate a width of 30 feet. Corners were jointed with a modified saddle notch, while the interior joints consisted of a plain saddle notch. Individual timbers were spliced together generally using a long end half lap, although a short end half lap and one short scarph joint was also noted. Also noted was a variation on the standard saddle notch joint, which included the addition of a third notch in each timber (Figures 21 and 22).

TYPE 2C

This type corresponds with construction occurring 1874 - 1883, during Phase II. Individual caissons, numbering 6 in sections 3 and 5, measure 30-110 feet in length. Historical documents indicate a width of 30 feet. Corners were jointed with a modified saddle notch, while the interior joints consisted of a plain saddle notch. Individual timbers were spliced together using a long end half lap. This caisson type differed from Type 2b in that the latter used primarily a long half lap to splice individual timbers.

TYPE 3

This type corresponds with construction occurring 1874-1883, during Phase II. One caisson of this type was present in section 5, measuring 70 feet in length. Historical documents indicate a width of 24 feet. Both corner and interior joints were of a saddle notch variety, while individual timbers were spliced using a random butt joint (Figure 23).

TYPE 4

This type corresponds with construction occurring 1874-1883, during Phase II. One caisson of this type was present in 5, measuring 60 feet in length. Historical documents indicate a width of 24 feet. Corners were fastened using a cross half lap, while interior beams were jointed using a housed saddle notch. Individual timbers were spliced using a random butt joint (Figure 24).

TYPE 5

This type corresponds with construction occurring 1884-1888, during Phase II. Individual caissons, numbering eight in section 6, measure 40—45 feet in length, with all but one measuring 40 feet. Historical documents indicate a width of 30 feet, which cannot be verified archaeologically due to the rock covering on the lake face of the structure. Corners are fastened with a housed saddle notch on the bottom half of each caisson, and a half height housed saddle notch on the upper half. Interior joints consisted of a housed saddle notch on the bottom half. Corners are fastened with a housed saddle notch that is offset from the corner by two to three feet, while interior joints consist of a housed saddle notch. This type differs from Type 8 by the type of corner joint only. Individual timbers are spliced using a staggered butt joint.

All the above types timbers used in construction measure one-foot square, and are fastened with iron drift pins. Types 6 , 7 and 8 were identified in the 2000 investigation and have been discussed above. Type 6 (Figures 25 and 26) corresponds with construction occurring 1884-1888, during Phase III. This type also corresponds with Type 1 from Lydecker and Cousins (2000). Individual timbers are spliced using a staggered butt joint.

(Figure 25) Profile of Type 6 caisson (Click on image for closer up view)

(Figure 26) Cross-section of Type 6 caisson (Click on image for closer up view)

Type 7 (Figures 27 and 28) corresponds with construction occurring 1884-1888, during Phase III. This type also corresponds with Type 2 from Lydecker and Cousins (2000). Individual caissons, numbering seven in section 7, measure 40 feet in length. Historical documents indicate a width of 24 feet. Timbers used in construction measure one foot square, and are fastened with iron drift pins. Corners are fastened with a corner half lap, while the interior joints consisted of a housed saddle notch. Individual timbers are spliced using a staggered butt joint.

(Figure 27) Profile of Type 7 caisson (Click on image for closer up view)

(Figure 28) Cross-section of Type 7 caisson (Click on image for closer up view)

Type 8 (Figures 29 and 30) corresponds with construction occurring 1884-1888, during Phase III. This type also corresponds with Type 3 from Lydecker and Cousins (2000). Individual caissons, found in section Section 7 and at the very northern end of Section 5, measure 40 feet in length. Historical documents indicate a width of 24 feet. Timbers used in construction measure one-foot square, and are fastened with iron drift pins. Corners are fastened with a housed saddle notch, while the interior joints consisted of a housed saddle notch. Individual timbers are spliced using a staggered butt joint.

(Figure 29) Profile of Type 8 caisson (Click on image for closer up view)

(Figure 30) Cross-section of Type 8 caisson (Click on image for closer up view)

Summary

The studies undertaken of the Burlington Breakwater have provided a wealth of information on 19th Century cribbing and construction techniques. Underwater investigations discovered that ten types of timber caisson were present in the two sections of breakwater, incorporating 12 types of timber frame joints. It was also discovered that the oldest part of the breakwater, constructed between 1836 and 1854, is in the best condition with respect to integrity. Historic and archaeological research has also been conducted on the Plattsburgh Breakwater. The Plattsburgh website can be viewed at http://www.nan.usace.army.mil/business/prjlinks/culture/plattsbg/index.htm . As funding becomes available, the Corps will study the other Lake Champlain breakwaters that the Corps built, owns and maintains.

References

Burlington Harbor, VT: 1834-193-, unpublished transcript of compiled records. U.S. Army Corps of Engineers Albany Field Office, Troy, New York.

Heintzelman, Andrea. "Colonial Wharf Construction: Uncovering the Untold Past" from The Log of Mystic Seaport 37(4). Mystic, Connecticut.

Lydecker, Andrew and Ann Cousins. 2000. Recordation of Portions of the Burlington Breakwater in Lake Champlain, City of Burlington, Chittenden County, Vermont in Connection with Proposed Structural Repair Activities. Prepared by Panamerican Consultants, Inc. for the US Army Corps of Engineers.

Lydecker, Andrew and Ann Cousins. 2002. Recording the Burlington Breakwater in Lake Champlain, City of Burlington, Chittenden County, Vermont in Connection with the Proposed Structural Repair Activities and Section 110 Responsibilities. Prepared by Panamerican Consultants, Inc. for the US Army Corps of Engineers.

* Copies of the Lydecker and Cousins reports are on file with the U.S. Army Corps of Engineers, New York District, Planning Division, New York, NY and Albany Field Office, Troy, NY; Vermont Division for Historic Preservation, Montpelier, VT; City of Burlington, Department of Planning and Zoning, Burlington, VT; Fletcher Free Library (Burlington, VT); Burlington High School Library; Bailey/Howe Library (University of Vermont); Burlington College Library; Champlain College Library; Chittenden County Historical Society; Lake Champlain Maritime Museum; and the Lake Champlain Basin Science Center.

For further information contact: Lynn Rakos - Project Archaeologist

Links

Vermont Division for Historic Preservation

Vermont Historical Society

National Park Service: Links to the Past

National Maritime Initiative