I have manipulated the photo on my computer.
If you look very closely, you can see there are two ships being built in the photo:
1) In the foreground is, it seems, the freestanding stern of a ship being built on perhaps, a pontoon , in the Oresundsvarvet building docks. It is too high to be sitting on the dock bottom.
2) In the background, larger building dock,, is the much longer hull of what can only be the OBO (and sister ship to Vianna) 'Vanessa' IMO 7110103, which was launched (floated out) on 27/02/1971.
It is very difficult to judge the size of the stern at 1) above. But I would make a guess that it not for the larger OBO carrier, and more likely the Nitsa 'class'.
The Nitsa was launched just 19 days later from your photo, on 19/11/1970.
So, it is your call on whether you think this stern could be finished off and attached to a ship in 18 days! I doubt it - in 1970!
It is more likely to be for the next in the Nitsa class, the 'Cepheus', yard no. 232, launched on 06/04/1971 and completed on 09/09/1971.