Lovisa Dal
Konservator
The Sulphur Threat To The 17th Century Warship Vasa
Författare
Redaktör
- Carlos A. Brebbia
- Timothy Gambin
Summary, in English
The royal warship Vasa sank on her maiden voyage in 1628. She was discovered in 1956 and in 1961, after 333 years at the bottom of the sea in the Stockholm harbour she was salvaged. Vasa, built mainly of oak, was one of the first major objects to be conserved with polyethylene glycol. She was sprayed continuously for 17 years followed by an 11 year long controlled drying procedure HBfors,
[l]). In 1990 the new Vasa museum opened and is now the most visited museum in Scandinavia with about 750 000 visitors each year. The summer of 2000 was unusually wet and in July, yellow-white precipitate was discovered on wooden surfaces on objects kept in the storage, in showcases and later on the ship itself. An international seminar was held in February 2001 and as a result a research programme was launched that involves scientists from Australia, Canada and Sweden. Surface as well as core samples have been analysed in this research programme by a range of chemical methods. The results so far show the presence of elemental sulphur in the outermost layers of the ship. This sulphur is now being oxidised in the museum environment to sulphuric acid. The process is probably catalysed by iron ions. Subsequently acid hydrolysis of the cellulose threatens the stability of the wood. Up until now about 1200 areas with precipitates have been observed on the ship and about 400 loose finds are affected. Treatments to neutralise the acid are currently being carried out and will be presented as well as experiments to extract the iron using strong chelating agents.
[l]). In 1990 the new Vasa museum opened and is now the most visited museum in Scandinavia with about 750 000 visitors each year. The summer of 2000 was unusually wet and in July, yellow-white precipitate was discovered on wooden surfaces on objects kept in the storage, in showcases and later on the ship itself. An international seminar was held in February 2001 and as a result a research programme was launched that involves scientists from Australia, Canada and Sweden. Surface as well as core samples have been analysed in this research programme by a range of chemical methods. The results so far show the presence of elemental sulphur in the outermost layers of the ship. This sulphur is now being oxidised in the museum environment to sulphuric acid. The process is probably catalysed by iron ions. Subsequently acid hydrolysis of the cellulose threatens the stability of the wood. Up until now about 1200 areas with precipitates have been observed on the ship and about 400 loose finds are affected. Treatments to neutralise the acid are currently being carried out and will be presented as well as experiments to extract the iron using strong chelating agents.
Publiceringsår
2003
Språk
Engelska
Sidor
175-182
Publikation/Tidskrift/Serie
WIT Transactions on The Built Environment
Volym
65
Fulltext
- Available as PDF - 290 kB
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Länkar
Dokumenttyp
Konferensbidrag
Förlag
WIT Press
Ämne
- History and Archaeology
- Other Natural Sciences
Nyckelord
- Vasa
- Shipwreck
- Waterlogged wood
- Iron
- Sulphuric acid
- X-ray spectroscopy
- Vasa (regalskepp)
- Konservering (museiteknik)
- Marinarkeologi
Conference name
First International Conference on Maritime Heritage, Malta 2003
Conference date
2003-03-24 - 2003-03-26
Conference place
Malta
Aktiv
Published
ISBN/ISSN/Övrigt
- ISSN: 1743-3509
- ISBN: 9781853129643