The Dutch wooden merchant vessel Vrouw Maria sank on October 9th 1771 in the outer archipelago of Finland near Nauvo. It was discovered in 1999 and has since been object of rumors about valuable cargo, lifting projects and, fortunately, is nowadays of scientific interest.
In fact, all rumors about this ship and its possible lifting have started a scientific discussion about whether it could be done or whether it should be done or not. We will contribute scientific facts about the condition of the ship particularly about the wood used for the hull.
The Baltic Sea represents an interesting extreme environment. In the case of this ship wreck, Vrouw Maria is situated in a depth of around 45 m surround by cold and slightly salty water. Here we expect wood degradation caused by soft-rot fungi and by tunneling or erosion bacteria. In July 2007 a sample has been recovered from the deck of Vrouw Maria and is currently analyzed.
We have until now used light and electron microscopy as analytical methods. However, molecular biological tools such as DNA analysis or other analytical methods are available to study wooden objects in more detail. Because fungi or bacterial exposure may directly cause fiber wall degradation we want to know who is degrading this hull.
Degradation is seen as a rapid weakening of the mechanical strength of the fiber wall, loss of the fiber wall weight density, and increase of the wood porosity. These structural and mechanical changes affect ultrasound propagation in wood which can be detected. These measurable parameters are sound velocity, attenuation, dispersion, and scattering. Thus ultrasound as such is the ultimate tool to investigate wood without destroying it.
Furthermore, from tiny samples we can extract DNA to analyze the present microorganisms living on and in the wood. From these we can individualize the causative agents of wood destruction.
We hope not only to give answers about what is going on with the Vrouw Maria but also to give information about the preservation and conservation of the ship, to predict lifting success and lifetime both, on the bottom of the sea or in a possible museum exhibition.