How quickly Scapa Flow could return as a fleet base

Would Scapa Flow need years of work before it could serve as a military base again?

Years for a full dockyard, but less for a forward fleet base, though either option would require significant investment.

The answer distinguishes two very different meanings of a modern naval base. Rebuilding Scapa Flow into a full dockyard equivalent to Portsmouth or Plymouth would take years. Reactivating its historical role as a forward fleet anchorage with support facilities would be quicker. Even that limited objective would not be immediate or cheap, because dispersed logistics and protection still have to be restored.