My Stiletto 27 had a portable toilet that stunk. Use the right chemical and it stinks less. Every time it is used a laborious haul/dump/clean process is triggered.
My PDQ 32/34 had a nice holding tank system that I had engineered to perfection. No odor, nearly like home. But it required space and weighed a good bit. Perfect for the PDQ, but totally unsuitable for the F-24.
We really only day sail the PDQ, and the head is only for emergencies. It didn't get used for years at a time, so we switched to WAG bags. Never used them.
I'd been poo-hooing composting toilets for years. I'd experienced some nasty ones in cabins and some friends had a bad experience with a Natures Head. In fact, both failures probably included elements of design and operator error.
I was asked to investigate the topic, and so I did. There was a long-winded article in Practical Sailor last month, covering both toilet design, absorbants, and anti-odor additives for the urine tank.
There are two keys to function:
- Separate the urine from the solids. First, the smell is greatly reduced, and second, the solids side it much drier, preventing it from getting wet and aerobic.
- Dry the solids. Like any animal dropping, once it is dry on the outside, there is little odor. That is the function of the absorbent; to speed drying, filter the air, and cover. It is NOT to cause composting. This is a desiccating toilet.
There simply is not room on a boat for true composting toilet. The process tanks months, requires temperature and moisture control, and continuous mixing and ventilation. Since you cannot effectively compost, then stop pretending and dry the waste instead. You can then take it home and compost it if you like, or double bag it and dispose of it like litter box scoopings. Your choice. The urine is odor-free once treated (see below) and can be disposed of easily.
I built a test version from a storage tub, a bucket and scraps to test the absorbents and additives. It was a crude thing, but in fact I used it in the basement bathroom for two months, during which it proved to be amazingly odor-free and easily to deal with. I was stunned. It was time to eat a large helping of crow. But I was happy to eat the crow, because the result was a truly user friendly head solution for my F-24.