One way to handle human waste without a porta potti, or the expense of the wag bag system, is to buy the Poo Powder product separately, use an 8 gallon garbage bag or whatever fits your "seat of ease", then store the waste in an odor barrier plastic bag, like that made by Opsak (amazon.com, or where ever). I assume these odor-proof bags were developed for NASA or the military or such. They can be re-used, and actually work very well. I cruise for 3 or 4 days at a time on my M17, and just keep the waste in an Opsak in the stern wet locker. It is completely non-intrusive once sealed. (David Patterson, M17 Cloud Girl, 1985 galley model, sailing on Lake Granby, CO)