I spent 4 months in / on her in 1973. If you are rebuilding "Somersby" I would totally disregard all pics of her as RFA "Reliant". The changes to her original appearance totally changed her outline. I believe that she was originally built as a trading cadet training ship...for Ropners, as you say. In the days when some enlightened companies actually had cadet training ships. Perhaps this function was one of the reasons the RFA took it over, as she would have had more accomodation and "leisure" spaces than would be found on a bog-standard dry cargo ship. As with all ships she "had her day", but right up to the end she was maintained as a yacht. Well, maybe not that well, but you'll get my gist. ("Stromness" took over the "yacht" crown....as I mentioned in a much earlier posting). As an RFA she had a mixed crew. Ships ratings and POs were all Chinese. The "Stonnery" were (as usual) a mixture of Janners and Wee Frees. And "us lot" (the Orifices) were another eclectic mix, but in general hailing from somewhere in the UK.
I have a rather sketchy GA drawing of her as "Reliant", and a rather nice aerial shot of her as "Somersby"...which I'll post when I find it. Sometime this evening I guess. BY.