Conclusions and Recommendations
The Maple Leaf site is a challenging environment for a controlled archaeological excavation. Techniques developed during the 1992 season overcame several limiting factors. The most important innovation was the silt barrier constructed around the bow excavation. This structure proved the utility of a "mini cofferdam" in a silty environment. The barrier diverted silt and trash away from the excavation, creating stable working conditions inside. Divers gained visibility in the current-free structure and the excavation remained open for over two months.
The level of accuracy reached in documenting the deck and the interior excavation was largely due to the silt barrier. Visibility allowed standard archaeological mapping techniques to be applied to the excavation while using a variety of underwater lights. Future site work will employ a silt barrier in conjunction with adequate lighting systems. Currently, a full size cofferdam is not economically feasible. In addition, the site is situated in the navigation channel and a cofferdam would pose a threat to navigation. As long as the level of activity on the site remains limited, the present working techniques should suffice.
A thorough analysis of the site environment and site formation processes remains incomplete. Water tests attempted in the aft cargo hold show general trends but were not conclusive. Dissolved oxygen levels were very low, accounting for excellent organic artifact preservation. River bottom sediment studies indicated anaerobic conditions would be present. Future testing inside the hull will help identify the mechanisms responsible for artifact preservation. This will lead to refinements in conservation techniques tailored to the Maple Leaf site.
Human activity and natural processes in the St. Johns River basin have been operating on the site for almost 130 years. Currents, tides, sedimentation, storms, and marine organisms are all natural factors affecting the site. Manmade influences have become important in the last century because the river acts as a conduit for waste removal. River basin development causing pollution includes urbanization, industrialization and agriculture. Late 19th century demolition activity caused extensive damage to the vessel's structure. Combined, all of these factors contribute to site formation processes. An analysis of the processes is currently underway.
The 1992 excavation found the forward deck suffering from extensive damage. A combination of historically documented episodes accounts for this damage. Initially, the torpedo explosion at the bow blew a large hole in the bottom, broke a hogging truss and knocked the mast out of the ship. Union and possibly Confederate salvage activity followed shortly after the sinking. Federal forces apparently removed the anchors. Missing deck planks may have been an attempt by the Union or the Confederacy to recover cargo. The last recorded activity on the site, before the current archaeological investigation, occurred in the 1880's. Roderick Ross used explosives to remove machinery and portions of the ship structure to provide safe river navigation. In combination, these activities have caused considerable damage to the area examined.
Numerous deck beams are broken and various loose timbers litter the site. The hull's structural integrity is uncertain but appears to be sound. Wood examined during the excavation was water logged but displayed little deterioration below the surface layer. Many unattached timbers, still buoyant, floated to the surface. It appears that any areas suffering major structural damage are supported by the sediment that encases the hull and fills the interior. The support offered by the sediment is similar to that supporting boxes packed in the hold. As long as the supporting sediment remains undisturbed the vessel will remain intact. Extensive excavation below the ship's deck may require shoring up broken deck beams. Future investigators working inside the ship must be aware of the potential danger of collapse.
All features encountered on the forward deck were thoroughly documented in 1992 except the starboard hogging truss. Time and weather restrictions forced a limited examination of the structure. A more thorough examination of this truss or another is necessary during future field investigations.
The forward hold test excavation supports the thesis that the torpedo explosion and post sinking site formation processes caused considerable damage to the vessel and to the packing containers inside. Fragments of broken, water worn and barnacle encrusted packing containers litter the interior. Most of this damage is a direct result of the large hole in the forward deck that exposed the interior to water movement. Material is better preserved deeper in the hold and possibly along the sides of the hull. Future excavations in the forward or aft hold will have to consider distribution of material based on varying buoyancy and density of material types. This factor, combined with limited working space available inside the hull, must be considered when establishing a recording system and deciding on levels of accuracy. If a systematic packing arrangement can be discerned, excavation levels should follow this manmade stratigraphy. Otherwise, arbitrary levels should be established to detect artifact distribution patterns. Discrete artifact associations must be maintained separately.
Future work inside the forward hold is not recommended under the current research design. Damaged materials make working in this space difficult and time consuming. Time and funding budgeted for field work is not sufficient to undertake an excavation that would result in definitive findings regarding material packed in this space. The present research design provides a site assessment but does not include extensive excavation in the cargo holds. Funding, however, is provided for test excavation, artifact recovery and conservation in 1993. This work should be directed toward further excavation in the aft cargo hold. This area holds a tremendous artifact collection that can answer questions concerning historical, sociological, anthropological, technological and economic aspects of the Civil War.
Following the research design guiding the Maple Leaf Project in 1993, field investigations will examine the engineering spaces. The final project year, 1994, will focus on the after deck and stern. Many important features of the vessel remain to be examined including engine machinery, boilers, paddle shaft, stern and rudder. This information will add to the collective knowledge concerning construction features and architectural elements of civilian ships used in the Civil War and particularly to Canadian Great Lakes steam vessels.