Since the Ijsselmeerpolders Development Authority is, among many other problems, faced with the difficulties of the conservation of big waterlogged wood constructions (shipwrecks), an advising board of experts from Holland was formed in January, 1973. In that year also the Zwammerdam ships were excavated, and it was decided that the conservation work should be done at Ketelhaven, so the board's first task was to decide what conservation process was most suited for these finds. After a study of several possibilities four methods were studied in detail. Considerations pertaining to the quality of the wood of the Zwammerdam ships, the results already obtained by others, and the possibility to automate the process led to the conclusion that impregnation with poly(ethylene glycol) 4000 in baths offered the best opporturiity, if based on a detailed knowledge of the distribution of wood quality throughout the finds.