Originally Posted by shadowraiths
......even if I had a head, I wouldn't use it anyway... as noted in the link above (concern about the smell).
The easiest marine heads to keep from smelling are the ones that are used routinely. You must, however, follow marine head protocol, which is different from land based. Much more flush water than most think, never anything (ever, ever, ever) other than human waste and toilet paper in the tank, good ventilation.... I could go on. The most common sin is the prolific advice to flush olive oil to lubricate the pump. Its among the worst thing you can do to generate smells in the holding tank. It skims along the top and kills the good bacteria that doesn't smell and creates the exact environment that bad smelly bacteria love.
A technique, when you may find yourself away for a few days with a partially full tank, is to restrict usage of the onboard heads to "number 1". You are likely to make more visits for that anyway and go ashore for "number 2". Not so inconvenient.