Regarding "black water". I have a
holding tank onboard, but prefer not to use it. My
family uses the
toilet facilities when in a marina, which is usually every night.
Last summer, I needed to transit the Caledonian
Canal to partake in The Malts
Cruise in the Inner Hebrides. I was concerned about the "black water" regulations.
My
chandlery in
Holland sold me some disposable paper/plastic
toilet bowl liners that one could place IN the toilet. Not to be flushed, but disposed of on shore. We would carefully store these used liners in double plastic bags before disposing.
Otherwise, I would start thinking "Port-a-Potty".