Analysis and research on the wood from the Ming Dynasty shipwreck,Nan'ao No.1,in Shantou city,Guangdong

In order to understand the state of conservation of the wood in the Ming Dynasty Wreck Ship,Nan'ao No. 1,in Shantou City,Guangdong,the S6 shifting board and stern deck were selected to for species identification and moisture content analysis. The physical characteristics and chemical composition of these samples were analyzed by several modern scientific methods. The results show that the woods used for the S6 shifting board and stern deck from the wreck,Nan'ao No. 1,are from the Chinese cherry tree. Contrary to the common Chinese cherry,which has an average moisture content of 68. 26%,that of the shifting board and stern deck is 327. 78%.Furthermore,the content of holocellulose in the shipwreck samples is significantly decreased. The ash contents and the 1% Na OH extract are increased to some extent. A large amount of soluble salt was detected,in which the main ions are Na+,K+,Mg2 +,Ca2 +,Cl-and SO2-4. In general,the concentrations of all ions are high,among which SO2-4is the highest. Many pyrite compounds are found,among which iron pyrite is the major dissoluble salt.Overall analysis shows that after soaking in the water for a long time,serious degradation had occurred to the organic membrane support of the wood from the wreck. Degradation of organic membrane components such as cellulose provides room for water and a large amount of salt. Thus the wood basic density is decreased significantly.So not only should water immersion be used to desalt the wood from the wreck of Nan'ao No. 1,but also suitable chemical adsorbents should be used to remove pyrite compounds.