MANAGEMENT AND ASSESSMENT FROM THE SEA BOTTOM TO THE SURFACE: ASSESSING UNDERWATER TECHNIQUES FOR LIFTING WATERLOGGED ARCHAEOLOGICAL WOODEN OBJECTS Introduction Organic materials are by nature prone to biodeterioration and thus they commonly survive in anoxic and dysoxic environments (Florian, 1987). The preservation state of waterlogged organic artifacts is frequently poor and makes them vulnerable to damage during handling and lifting (Bowens, 2009). In most cases, removing a waterlogged organic artifact from its burial environment, upsets its chemical and mechanical equilibrium and may accelerate the deterioration process (Rodgers, 2004). Therefore, the lifting method chosen for its transport to the atmosphere is of great importance, since it may also protect it throughout the journey to the conservation lab. Lifting is commonly carried out by underwater archaeolo- gists, conservators or experienced divers, who often need to act in a limited dive time, conduct the lift in bad underwater conditions, and deal with several practical constraints of working underwater all of which may increase the risk of mechanical damage (Robinson, 1981). Unfortunately, no guidelines exist for practicing lifting and the literature Helen M. Bardas* and Anastasia Pournou University of West Attica, Dept. Conservation of Antiquities and Works of Art, Ag. Spyridonos str., GR 122 10 Aegaleo, Greece Abstract Retrieving waterlogged archaeological wooden objects from the sea bottom is an irreversible and potentially damaging action. Objects in a poor state of preservation are challenging to excavate, stabilize, lift, and transport to the conservation lab. In an underwater excavation factors such as limited dive time, difficult underwater conditions, and the practical constraints of working underwater, increase the risk of mechanical damage to objects during lifting. To date, the literature lacks comparative studies on lifting methods, therefore this project set out to investigate four commonly employed underwater techniques and comparatively assess their impact on waterlogged archaeological wood. These included i) basket lift, ii) lift on a solid surface, iii) block lift and iv) the use of carbon fiber reinforced casts. Evaluation of each method was based not only on its impact on the object but also on additional criteria, such as the required time, ergonomy, ease of application, cost, and accessibility of materials. Repeatability and statistic validity of the obtained results had to be ensured. Thus besides the original waterlogged wood samples, mock-ups that matched some of the physical characteristics of waterlogged archaeological wood were also used. Various materials were investigated for the creation of the mock-ups and “floral foam” was eventually chosen after several preliminary tests. Floral foam can absorb water up to 98% of its volume, has negative buoyancy, and its surface is so sensitive to dents and scratches that any kind of mechanical damage is visible. Packing and wrapping materials such as foams, plastic padding, sponges, were also tested in a custom-made hydrostatic pressure chamber in order to observe their dimensional alterations under hydrostatic pressure and predict their underwater behaviour. Results obtained, under the experimental conditions used in this study, demonstrate that the basket lift was the best lifting method followed by the lift on a solid surface, the block lift and finally the lift with carbon fiber reinforced casts. This work presents the pros and cons of four lifting methods in order to assist the conservator-diver in choosing the most appropriate methodology based on the criteria and requirements defined by the underwater excavation. Keywords: underwater lifting techniques; floral foam; polyurethane foam; basket lift; block lift; carbon fiber.