@garynewport , see this thread.
By the way, you’ve previously mentioned you now have several of the books on modern Fortran.
I suggest reviewing those books closely and gaining good facility with modern Fortran before proceeding with your code. Because going by your original post here suggests you might eliminate what might be marked as obsolescent in the standard i.e., EQUIVALENCE only to create data duplication in your code that might lead to adverse consequences.