I recently replaced our old
marine head with a Theatford Porta-Potty. We seldom overnight more than 2 or 3 nights and sofar it has worked well. I debated on getting the model with pump-out fittings but we don't usually get into
marinas for pumpout. Its not that difficult to take the PP into the house and empty and not messy at all.
About your drawing, how would you
pump the PP out through your through-hull or is it just left over from your old system?