Conservation of Ancient Timbers from the Sea 307
6 Conclusions
With the passive storage of waterlogged wooden artefacts, the major problem
is not that we do not have adequate storage methods available, it is in recog-
nising the limitations of these methods with respect to the size of the artefacts
that can be treated within the restrictions of time, funding and facilities avail-
able. Such considerations, in conjunction with data available from numerous
experimental investigations should be taken into account when deciding upon
the most suitable conservation method for the short- and long-term storage of
waterlogged archaeological wood.
Of the methods discussed, gamma irradiation is the most effective method
for inactivating wood-decay organisms, and is the only method that provides
complete sterilisation. The surface dose for most timbers of the size usually
stored by wrapping is 20–30 KGy and it is the only treatment that meets the
criteria for an ideal storage method. For large intact structures such as wooden
ships and boats, a low temperature spray is the most successful storage method
tested. Methods other than the use of biocidal chemicals to maintain clean
water for spraying, include the use of fish (species of perch) and snails in water
storage tanks.
Reburial of waterlogged wood in the marine environment is now becoming
increasingly common practice in managing wooden historic wrecks in situ,
predominantly due to the prohibitive conservation costs. Remedial strategies
that are appropriate and cost-effective are fundamental pre-requisites for the
successful long-term management of underwater wreck sites.
Figure 20Phase diagram of water