As always, the ship engineering became a challenge. The toilet floor had about a cm thick tile on top of about 3 cms of concrete over 2 cms of black tar type stuff.
Although the toilet and wall was removed some time back the grey platform at the base was still in place for each toilet like some foundations for a throne on the black and white masonic temple floor it. The flooring came up relatively easily in about 2 hours of jackhammer activity removing one room's worth. What remained may require explosives.
The grey platform, if a lump of concrete would have been merciful. Concrete I can handle. What they had done is similar to the old galley cooker floor. The had created a metal box welded to the metal floor (concreted in around) and the grey is a piece of very old, very very very hard seasoned hardwood. The jackhammer just bounces off. The chisels make no impact!
The only way to get this out will be drills and hole cutters. When the wood is removed the metal box can be cut away and then and only then can the concrete at the back be removed.
Then the woodwork can progress.