Excavation and Mapping
Nearly all ship documentation was completed by summer field schools offered by East Carolina University’s Program in Maritime History and Nautical Archaeology. SJAEI provided assistance and follow-up work. Field schools were held during July in 1992 and 1993, and June in 1994. Students, staff, and faculty numbered sixteen in 1992 and 1993, and thirteen in 1994. In 1992, site excavation began in the forward area of the ship. The bow offered a definitive starting point while permitting the work area to expand as time allowed. In 1993, investigations concentrated on the engine room, then moved to the aft deck in 1994.
Over the three summers, diving operations took place from the SJAEI dive platform consisting of a 28 foot spud barge rafted to a 28 foot pontoon boat. These vessels are named Tater and Mud Puppy, respectively. The spacious area housed a drawing table, two dredge pumps and a large work area for documenting recovered materials. Large concrete anchors were placed off-site to moor the dive platform. Various small boats provided transportation to and from the site.
In 1992, East Carolina University students and staff completed all underwater work using normal scuba and underwater lights. During the following two years underwater work utilized modified scuba gear incorporating a redundant air system and a full face mask with wireless communication. This system offered additional safety to divers. Many entanglement hazards are present on the site and communication gear allowed a surface tender to monitor diver air consumption and activity. It also allowed two or more divers working together to complete complicated tasks.
Approximately four to eight feet of sediment covers the site. Using water induction dredges, divers moved approximately one thousand cubic yards of overburden. Although the silt barrier kept river-borne debris and silt out of the excavation, periodic cleaning was necessary to remove silt disturbed by divers during site documentation.
In accordance with state and federal environmental permits, water turbidity from the dredge outflow was monitored every 2 hours during dredge operation. Water samples were taken 100 meters down current from the dredge exhaust and compared to background samples taken at the same time. Permit stipulations required dredging operations to cease if dredge plume turbidity exceeded 29 Nephelometric Turbidity Units (NTU) above background levels. Comparative measurements normally averaged 1 NTU or less. The highest recorded level was 13 NTU's, below the permit limit.
The river bottom environment at the Maple Leaf site is hostile to divers and hindered detailed recording required for archaeological documentation. Therefore, an attempt was made to create a controlled working environment. In 1992, an underwater structure was built to provide better working conditions on the site. The fence-like structure began at the bow and extended aft 50 feet. It was constructed of 4 by 8 foot galvanized wire panels covered with geotextile silt barrier fabric. This silt barrier diverted tidal currents, deflected the bottom silt layer and kept sediment and trash from filling in the excavation. Three modular silt barrier units, 24 feet square, were built to enclose the bow during the 1992 field work (Figure 12)(Cantelas 1993:19).
The modular design was abandoned in 1993 and 1994 in favor of building a single large structure around the field school work area. This had the advantages of completing the barrier before field school started, and allowing students to spend more time documenting the site. Figure 13 illustrates the shape and location of the silt barriers built each year from 1992 to 1994.
The silt barriers proved successful in diverting clear river water down to main deck level, thus providing adequate visibility to map and document ship structure. Artificial lights penetrated 6 inches to 3 feet in the river water. During times of extremely low visibility, divers used water filled bags to take measurements. The bag was sandwiched between the face mask and tape measure with a light shining in from the side. This technique proved very accurate but time consuming. During dredging operations large amounts of suspended silt temporarily eliminated all visibility and required excavation by feel alone.
Excavation and Mapping
In 1992, overburden removal started at the stem and moved aft 55 feet. Both the port and starboard sides of the bow were exposed but excavation was limited to the fig 12 fig 13 starboard side further aft. Excavation ended just aft of the forward hatch, very close to the engineering spaces. Several features were exposed including the stem, windlass, hogging truss, forecastle hatch, and the forward cargo hatch (Figure 14).
The 1993 excavation began just aft of the forward hatch and proceeded aft to the paddle shaft (Figure 15). The area exposed included portions of the forward deck, the upper portion of the engineering spaces and the intact starboard guard. The open unit extended forty-five feet along the length of the ship, from 60 to 105 feet on the baseline, and stretched 22 feet across the ship, from the baseline to the edge of the starboard guard. Trenches were dug at the forward and aft end of the excavation. The short forward trench relocated the forward cargo hatch found in 1992, and provided continuity between the two areas. It also revealed considerable scouring caused by river currents during the intervening year. Eight feet of mud covered the cargo hatch in 1992 while only four feet covered the area in 1993. A trench on the aft end of the excavation exposed the walking beam and paddle shaft connecting rod.
The following year, 1994, excavation began at the rudder post and moved forward to the paddle shaft (Figure 16). Several features examined include the rudder post, hogging truss, starboard guard, cabin soles, paddle wheel, and aft cargo hatch opening. The excavation unit extended approximately seventy feet along the length of the ship, from 110 to 180 feet on the baseline, and stretched twenty-two feet across the starboard side of the ship.
Work beyond the scope of the field schools included excavations in the forward cargo hold in 1992, and aft cargo hold in 1993 and 1994. St. Johns Archaeological Fig 14 fig 15 fig 16 Expedition, Inc. volunteers accomplished this work under archaeological supervision. While an analysis of the cargo and its spatial distribution are not part of this thesis, architectural elements found in the cargo hold are critical to any analysis of the ship. Currently, only the interior of the aft hold has been examined. The internal structural investigation was limited to the small area cleared of artifact material in 1988, 1989, 1993, and 1994.
Mapping techniques remained consistent from year to year. A recording grid was set up using the permanent cable baseline stretching from the stem to the rudder stock. Each end of the ¼ inch galvanized wire baseline was secured to metal clamps placed over the stem and rudder post. The site datum is the aft face of the stem post where the cable attaches to the clamp. All measurements taken on the ship are in reference to this point. The cable is marked at ten foot intervals with bronze clamps.
To create a mapping grid, transverse lines were extended perpendicular to the baseline. Polypropylene lines were fastened to the baseline at ten foot intervals and stretched to the starboard guard. The end of each transverse line was triangulated from the baseline to locate each grid. Because of the high vertical relief from the baseline to the guard, measuring tapes were placed on the ship's deck directly under the transverse lines using a plumb bob. The Polypropylene served to guide students to grid units while actual measurements were taken from the tapes. Each transverse line received a letter designation for recording purposes.
The narrow units created by the transverse lines running athwart ship were further subdivided. Individual mapping grids were laid out between the transverse lines in five foot segments. This established grid units measuring roughly five by ten feet, extending from the baseline to the edge of the guard. One student was assigned to each grid. Within the grid, features were mapped using offset measurements and triangulation from measuring tapes placed around the unit border. Each evening, the day's data was transferred to the site map. Any errors or questions were resolved the following day.
SJAEI instituted a provenience system in 1988 while excavating in the aft cargo hold. The system used recovery numbers, or lots, to specify a group of artifacts collected from a particular area such as a box. Each item within the recovery area, or box, receives an individual artifact number. Generally, two types of artifacts, exclusive of modern trash, were encountered while excavating the Maple Leaf's deck. First, there are disarticulated timbers from the wreck which are present in the overburden. Smaller items were found on the deck itself.
During the excavation phase, many buoyant, disarticulated planks and timbers rose to the surface. Debris litters the site as a result of Ross's work in 1883. When excavators removed overburden holding debris in place, a great deal of it floated to the surface. The surface support crew kept a continuous lookout for "floaters" and retrieved many pieces in a small boat. The recovered wood was given a general provenience number designated for the overburden removed from a specific area. The recovered material was then identified, drawn, described, and photographed in black and white. After recovery and documentation, the material was tagged with a catalog number and returned to the wreck for on-site storage. This practice allowed artifacts to be documented with minimum damage and returned to the site environment without incurring extensive conservation costs.
The smaller items found on the deck were plotted and brought to the surface. Documentation included black and white photographs, a written description, and a measured drawing. Each piece was assigned a catalog number utilizing the provenience designation system instituted by SJAEI, then taken to the conservation laboratory for treatment.