In 1925, a large wooden structure was impacted during dredging works in the Schlei, a long Fjord in Schleswig-Holstein in Northern Germany. The dredger encountered a wall of oak timbers along the northern perimeter of the intended shipping channel in the Grosse Breite. Although the discovery was eventually reported to the responsible archaeological authority, a considerable amount of timbers were removed prior to the notification and no further action was taken by the museum.
The structure was associated with a protection of the shipping lane and quickly forgotten, although local historians attempted to raise awareness at the time. In 1992, Willi Kramer, an archaeologist working for the state authority in Schleswig-Holstein “re-discovered” the structure and attempted to find what might be left. This lead to four surveys and excavations in the years 1995 to 1997. The structure was located (1995), and partially excavated in 1996 and 1997. In addition to the diving work, a number of geophysical surveys were undertaken, last by the Hafen University Hamburg in 2008 and 2010.
In 2014 the submerged barrier was subject of the annual summer field school of the Maritime Archaeology Programme for the first time. The field school was organised in cooperation with the archaeological state authority. The main objectives were to locate the structure, establish its extents, describe the construction and obtain a number of dendro samples. While these objectives were met, the final report for this field school is still outstanding and will be published in conjunction with the report from 2015. The extent of the structure was established with divers and also by using a parametric sonar. Although the survey results obtained during the field school are usable, they are not of very good quality, and the survey is redone later in 2014 by Innomar from Rostock. Dendrosamples obtained all point to the same construction dates in the 730’s, however on one of the boxes two timbers date to 734 and 737 respectively.
In December 2014, timbers related to earlier excavations were viewed at the timber storage facility of the ALM in Schleswig. These offered some information on a possible superstructure and further informed the project.
In order to understand the connection to land on Reesholm, a magnetic survey was undertaken by Kiel University in February. No wooden structure could be detected on land, but a number of poles were observed eroding out from the sediment on Reesholm. A final geophysical survey with sidescan sonar was carried out in the area, where initial contact with the structure was reported by the dredger in 1925. Although no in-situ structure was visible above the sediment in this area, a few anomalies, which warrant further investigation by divers were spotted.
In 2015 another field school took place in the Schlei, this time in close cooperation with the Archaeology Institute at Kiel University. The aim was to improve our knowledge and understanding of the submerged barrier in the water off Reesholm. The work carried out in 2014 and early 2015 and the analysis of the accessible data generated during the 1990’s left a number of open questions:
- What was found in 1925 and are there any remainders of this structure left on the seabed?
- The course of the submerged barrier can be followed running from the east towards the tip of Reesholm. On Reesholm the barrier could not be detected in the same form (wooden boxes) during a magnetic survey carried out on land on the 19.02.2015. However, assuming a defensive function, the barrier should continue westwards. On the tip of Reesholm, a number of poles were observed during the land survey. Also, in 1997, poles and timbers were found west of Reesholm. How far westwards, and in which form does the barrier continue?
- Related to the question above, what form does the structure have on the peninsula and are there any traces of this left?
- Although the fieldschool in 2014 succeeded in collecting data about the construction of the boxes a number of questions remain. Can we find evidence for possible structures around the boxes?
- What can we find out about a possible superstructure? The survey of timbers lifted in the 1990’s has yielded interesting results regarding a possible palisade. Can a survey of the area south of the boxes and a detailed recording of loose timbers in this area provide more information?
- How long was the structure in use? Can we find any evidence for repairs or continued use?
All of these questions could be successfully answered during the recent summer field school. We will be working on the publication this autumn, but in the meantime