Down the dock, weekend liveaboards installed a composting toilet and give it great reviews. Our full-time liveaboard friends, a few slips away, decided to follow suit. We decided to as well and went with the Nature's Head . Our brand was designed by liveaboards who wanted to improve upon the quality and ease of composting aboard.
Truth be told, it was a very, very yucky process and I will forever be amazed at how well my husband did this job. Unhooking and then pulling out the holding tank (which was kept under our port side couch cushions) was incredibly messy. The final step in unhooking the tank caused a waterfall of grossness that went directly into the bilge and in any crevice that was open and available. Quickly, my husband instructed me to head up to the local liquor store to buy two big gallons of vodka (for disinfecting). I did just that, raced into the alcohol mart, picked out the cheapest and largest containers that I could find, and at the register the owner smiled and said, "Big party tonight? Heh, heh."
One gallon used for disinfecting (another I'm surprised my husband didn't drink that night) and a shop-vac completely ruined by all that it had to suck up led to a successful removal of the tank and a space ready for installation of the Nature's Head.
The toilet separates liquids from solids, uses either peat moss or coconut husk to compost the solids, and liquids are collected and later disposed of properly. There's a little fan in the solid tank which moves air around and pushes the light gas byproduct outside through a hose that runs up through the deck.
So far, it works great and we're happy that we no longer have to carry around of dispose of what composting can now take care of for us. Now there's just a lot of jokes among friends that they will not eat any vegetables that we grow this summer...