Hi
Note that Mammoet states: "the possible salvage"

The Norwegian Coastal Administration - NCA's advice to the Norwegian Government is to cover (encase) the wreck. If the Government on the other hand should decide to raise the wreck, NCA's recommendation is to go for Mammoet's alternative among other that has been considered.
Here is a link to NCA's English page about U-864: [www.kystverket.no] and here is a direct link to the summary of the report released November 10th 2008: [www.kystverket.no]

Vidar