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Object: Wreck of the three-masted galliot St Mikael which sank in 1747
Area: Finland, Finnish Archipelago
Municipality: Nauvo
Village: Borstö
Sea charts: C-sarja 753 (1996) 1:50 000
1033 05 Borstö 1:20 000
The St Mikael is a three-masted galliot of Dutch type. It is still an intact ship which rests on the seabed on its keel as if it had been put into dock. The lower parts of the three masts have remained in vertical position and they rise to a depth of approximately 20 metres.
The St Mikael is a rare wooden wreck, since its hull is still almost intact. The wreck lies at a depth of approximately 40 metres on a clay seabed, slightly inclined on its port side. The wreck is approximately 24 metres long and just under 7 metres wide. All three lower masts are standing, and the caps of the foremast and mainmast are still in place. The masts rise to a depth of approximately 19 to 24 metres. The deck covered by a sediment layer appears to be intact, but the fore and aft half-decks are damaged. The beams of the fore half-deck are well preserved but many of the deck planks are missing. Deck planks at the aft half-deck are almost completely missing. At least one deck beam has collapsed at its starboard side and is aslant. The aft half-deck and the structures underneath it in a location where the former cabin and possible storage facilities were situated have collapsed, and the collapsed area extends all the way to the lowest floor planks.
The deck of the St Mikael is covered by fine sediment of organic origin, which in places is tens of centimetres thick. The thickest sediment layer is found on the port side of the wreck. The sediment also fills the interior of the wreck, where it is found in drifts on structures and cargo at an average distance of 70 to 80 centimetres from the deck level.
The almost Arctic conditions in the Baltic Sea together with the low-salt water have preserved the St Mikael in exceptionally good condition. The depth at the site has also protected the wreck against damage caused by packed ice and recreational divers.
An entire wooden wreck such as the St Mikael is a rarity on a global scale. In salty waters, the wood is usually devoured by the shipworm (Teredo navalis). The St Mikael was made mainly of oak, which keeps especially well in the Baltic Sea. The masts of the St Mikael are a part of its unique character, and as they reach up to a depth of 20 metres, they are at particular risk. A piece of antiquity must not be damaged for instance as a result of faulty anchorage.
The St Mikael is protected under the Finnish Antiquities Act, and it is under special surveillance by the Maritime Museum of Finland. Moreover, in 1999 the Southwest Finland Regional Environment Centre confirmed, at the proposal of the National Board of Antiquities, a prohibited area for the St Mikael, having a diameter of hundreds of metres. Within this area, certain activities straining the wreck – such as anchorage, certain forms of fishing and recreational diving – are prohibited.
The St Mikael is one of the most important underwater sites for the Maritime Museum of Finland. The condition of the wreck is monitored in order to guarantee its preservation. Diving on the St Mikael requires a permit, and diving is strictly controlled because of protection, since the present museum personnel have to do everything necessary to preserve the wreck in a good condition to the next generations.
A condition monitoring system was established for the wreck of the St Mikael in conjunction with the field work carried out in the autumn of 1998. The system is based on 20 measuring points, providing data on deformations in the hull (such as inclination of structures or imminent collapse) and on the position of the masts and the entire wreck.
Even though the St Mikael is relatively intact, its condition will not remain as it is now. All wrecks are subject to biological, chemical and physical processes, some of which are preserving and some degenerating. The processes are also affected by diving and research, which is why they often strain underwater sites. Archaeological field work on wrecks is often of an interfering nature even in cases when no actual excavation work is carried out (e.g. measurements and condition evaluation). In addition to mechanical stress, even the divers' exhalation gases, agitation of the sediment layers or materials used in the research instruments and tools may wear the wrecks.
It is necessary to monitor the condition of the St Mikael so that the damage and decay cannot progress unnoticed. The objective of monitoring is to follow the deformations in the primary structures in a manner which can be used for reference purposes. The monitoring carried out needs to be anticipating and aim at special monitoring of any detected changes and at immediate structural supporting of damaged locations. Because of the structure of the wreck, the damage is often multiplied. As an example, problems related to the mounting of masts are reflected in the deck structure and vice versa. Damage in the deck and side structures and fore and aft body in turn have an impact on both the hull and its contents, i.e. also on archaeological material which has not been examined to date. Condition monitoring calls for regular and methodologically valid surveillance of the selected measuring points. All measurements and observations have to be carried out using identical methods and criteria. This is possible because of a coded measuring point system, a measuring system which minimises the error margin and a standard measuring method, all established for the measurements. The objective is to obtain an identical amount of information on the wreck from year to year.
Until the spring of 1998, diving on the St Mikael was difficult because the support ships had problems with anchorage in the area. The wreck is surrounded by an even clay seabed, which is organically sedimented in places. This made it risky to drop the anchor in the immediate vicinity of the wreck even when the conditions were favourable let alone during strengthening wind and changing wind direction which might lead to the anchor not holding. The biggest risk scenario was the uncontrolled dragging of an anchor or anchor chain against the wreck or its masts. In the spring of 1998, a specifically-designed anchorage system enabling multiple point mooring by the support ships was installed near the St Mikael. Therefore, it is now safe to work on the wreck.
© Anna Nurmio-Lahdenmäki 2000
All stationary antiquities are automatically protected under the Finnish Antiquities Act (295/63). It is legally prohibited to dig or cover antiquities or to interfere with them in any other manner. The Act does not define antiquities on the basis of their age; instead, it uses expressions such as ancient, dating from ancient times, from the age of heathenism etc. Antiquities protected by the Act include ancient graves, graveyards, dwelling places, rock paintings, sacrificial stones and other places of worship, fortified hills and ruins of prominent buildings. Old objects presumably more than 100 years old, found on the ground and having no known owner, must be delivered to the National Board of Antiquities for examination. Shipwrecks more than 100 years old are also directly protected by virtue of the Act.
The National Board of Antiquities is responsible for the protection, research and management of antiquities. The National Board of Antiquities has the exclusive right to study, manage and mark antiquities or to grant a permit for this type of action. Since 1995, the respective regional environment centre confirms the boundaries and protective areas of antiquities at the proposal of the National Board of Antiquities or the land owner. The environment centre may also grant a permit concerning work on the antiquities, but if the National Board of Antiquities objects to such permit, the case must be subjected to the Ministry of Education for ultimate decision.
The Antiquities Act restricts the use of land significantly, and the protection rules need to be taken into account as early as when drawing up the land use plans. The Act stipulates that in all public projects such as the construction of roads, railways, canals and airports, regulation of waterways or zoning, it must be verified in good time whether the execution of the project may concern stationary antiquities. If this is the case, the constructor is liable to compensate for the archaeological studies required by the project. The procedure is the same for major private projects. The National Board of Antiquities, however, covers the costs in small private land use projects. If a public project requires that a nationally significant item of antiquity is exempt from protection and if the National Board of Antiquities argues that this exemption is not possible even after the research has been conducted, the matter is forwarded to the Government for ultimate decision. However, almost every time negotiations between the engineer/constructor and the National Board of Antiquities have led to such changes in the zone plan or project plans that it has been possible to retain important antiquities intact. Finland signed the European agreement concerning the preservation of archaeological cultural heritage in 1994. The agreement became effective on 25 May 1995. The Finnish Antiquities Act follows the main principles stated in the agreement.
© www.nba.fi 2000