The findings and work of the Marine Archaeology Center at Ketelhaven, part of the Ijsselmeer Polders Development Authority, are reviewed. Methods used include stereo-photographs taken by helicopter of the site; polyethylene glycol impregnation of some, not all woods; controlled drying of waterlogged wood; and wet housings for vessels to be treated in the future. Many artifacts have been retrieved and are exhibited with treated marine vessels in the Museum for Marine Archaeology, Ketelhaven, which opened in 1971. -- AATA