You certainly seem to be well experienced so I have a couple of questions I have not seen addressed before.
1. What happens you use the boat for a weekend then leave during the week and you get a hard frost? The pee jug can be emptied before you leave of course but what happens to the solid tank? Will it freeze solid and their for can't be used.
2. What happens if you have some severe diaria for a while or for example have to take the prep for a colonoscopy that means you have diaria for at least 24 hours.
I'm not knocking the product and if the above questions don't have fun answers the scenarios they represent may be so rare as to not matter but I was wondering what you have found out.
3. Do men have to sit to get the urine to go in the correct place?
David, others here have more experience with composting toilets. As I mentioned, I've had mine for over 2 years and am 100% happy with the choice. To answer your questions:
1) A hard frost (say just below freezing) I believe would be no problem. Solid water freezes and expands, breaking the walls of pipes. In the case of the composting chamber, we are dealing with a light, fluffy pile of coconut fibre which I can't see causing any problem even if were to freeze. I live in Brazil so freezing never enters my thoughts!!
. Perhaps someone from more northern states or Canada will chime in with their experience or you can contact Nature's Head or Air Head directly.
2) Severe diarrhea will be a messy problem with ANY toilet David! The bowl of the composting toilet can be cleaned with a paper towel and the cleaner of your choice. You can put the paper in the composting chamber, although it will fill it quicker and will require much more time to compost. I routinely clean the bowl with a paper towel and a misting of vinegar and water (although as I mentioned above, never has anyone "missed" the hole to the solids chamber). Unless you have a medical condition that gives you frequent diarrhea, I wouldn't worry about it.
3) Yes, you have to sit to pee, at least with the Nature's Head (others I can't speak of). I think standing to pee is the main cause of urine finding its way into the composting chamber as it flows up over the lip with the pressure of the delivery. Most boat guys sit to pee anyway, don't they?
I hope this helps.