This is very interesting. The man in the picture looks to be cutting an 4" or 100mm armour plate. I believe that the steel beams in the back are deck support beams, which would mean he is cutting the belt armour and the ship has about a 25 to 35 deg list. He is wearing a standard forage cap. The uniform is that of a Matrosen-Gefreiter. The star just above his rank insignia is a trade badge of a Deck rating (Bootsmann Montrose) The only problem with the trade badge is that is was to be worn on the upper "left" arm, not the right as the picture suggests. If this is correct the picture is reversed.
I think I'm going to need a few clues, because Kriegsmarine personal should not be part of the breaking up of a ship.