The standard procedure for conserving the fabric of a historic shipwreck (its hull) has been to either keep it constantly moist or impregnate it with a polymer, like polyethylene glycol (PEG). The Delaware Division of Historical and Cultural Affairs recently installed a new sprinkler system to help conserve the hull of H.M. Sloop DeBraak, a 1798 British wreck raised in 1986.
However, as this interesting article points out, rising petroleum prices and evolving conservation science are causing some institutions to consider other means of conserving shipwrecks removed from their watery graves. Conservators at Texas A&M University are at the beginning of a project to freeze-dry the hull of La Belle, a supply ship that sank in 1686 while part of La Salle's Mississippi colonization expedition. A similar project is underway in Wales, where a 15th-century ship was discovered in 2002 during waterfront excavations. Both ships have been partially disassembled, and will be slowly freeze-dried to prepare them for eventual museum display.
The hull of La Belle, soon to undergo freeze-drying conservation. AP Photo/Texas A&M University.