OK.... here we go....
That's the point I was making earlier. This is not actually composting which is a very environmentally safe and responsible activity.
1. Urine goes over the side. If it's no big deal then invite your neighbors to pee in your pool!
Have you considered what wildlife does when it has to go potti? I can assure you that they don't hold it until they are away from the water. If your sailboat can produce as much urine in a year as one whale in one shot, I'd be mighty impressed. Backyard pool doesn't even fit into the same category as a natural ecosystem that both feeds on the nutrients, and is HUGE in comparison.
2. Pooh gets dumped somewhere on land, could be laced with fecal bacteria that can cause sickness (unless you store it for a few years - yah right!).
Are you aware of what sewage plant effluent contains? Look it up, I'm not a teacher, and I'm sure you're old enough to look into the stats for your own municipality.
Portable or pump out heads are way above this standard and can easily be disposed of in a responsible and non-environmentally fashion.
You either care or you don't - karma.
Either you spout rhetoric based on xenophobic opinion, or you get the facts and you don't. - Science.