Page 194 - Manual for Activities directed at the Underwater Cultural Heritage

 © Archivo del Centre d’Arqueologia Subaquàtica de Catalunya. Extraction of a Haltern 70 amphora from the site of
the Culip VIII (1st century BC) Cadaqués, Girona, Spain. Recovering objects of underwater cultural heritage is a very difficult operation and it is thus important to ensure effective and efficient support for fragile artefacts, in particular when lifting, handling and transporting objects.
artefacts can collapse during the recovery if they are not effectively and efficiently supported. Support is even more cri-tical for organic materials or glass. It is thus of primary importance to create and bring an adapted support for each fragile artefact to be recovered.
• Lifting, handling and transporting recovered objects
The lifting, handling and transportation of artefacts is very sensitive and it requires careful pre-planning and adap- tation to suit the specific needs of individual projects, depending on the fragility, significance, location, size and mass of objects, as well as project objectives and available resources.
Prior to lifting artefacts from the seafloor, all finds should be completely uncovered from the context (unless the retention of the surrounding context is important). It is important to move the objects very slowly under the water in order to keep the physical pressure
exerted on them to a minimum. There are a number of methods to support finds during lifting, such as flat sheets, self-seal plastic bags, bubble wrap, plastic strings, cotton ties, pallets, large trays, block lifts and purpose-built devices. In any case, it is advisable to allow for decompression stops during lifting. If decompression occurs too quickly, the object may explode or break. The transmission of objects from the divers to the platform/boat staff should occur slowly and gently. Storage bins or containers should be readily available. Particular attention should be paid to large and fragile objects. The exposure of all finds to air and light should be kept to a minimum.
Underwater artefacts should benefit during their transport (in the water, from the site to the workshop or from the workshop to the conservation laborato- ries) from special protection measures.
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Conservation and site management