It is my old CHANT tanker, which still resides within the Portsmouth Model Boat Display Team, but sadly not mine any more. It is a 1/32 scale model build on a hull supplied by many people over the years, including ABCO, Models By Design, and I think it currently resides with Mountfleet Models. I ballasted this model to represent light load, hence the scum line cutting diagonally from bow to stern. Many photos show these ships up a river somewhere sitting at a jetty at low water with the stern down and the bow up in the air. Ample opportunity for a grubby old scum line to develop.
I think this model was about 55 inches long, a smaller 1/48 scale hull was also available, and may still be now.