Ken and Heidi Maitland, Victorious, 37VT26, have solar panels and enjoy being on a mooring and anchoring out. Having a composting toilet allows them to be more self-sufficient. This also solves the problem of finding pump outs. On their long voyage last winter they found many times that they were out of service at marinas and gas docks. This prompted them to replace their conventional toilet during the trip.
In their own words
We have used both main types of composting toilets: Air Head on their LNVT, and Nature's Head on their previous boat. Both types have a mostly pleasant odor, which is the smell of peat moss used in the toilet tank. There have been a few situations when the composting toilet didn't work as designed and can be traced to use by a visitor who did not follow the simple directions (in our case, children). Check the manufacturer's comments on-line for dumping the contents.
INSTALLATION: For the shelf it sits on: make a cut out wide enough for the toilet and the crank handle; for us we lowered the base 6" (still about 3-4" above the floor of the head). If you lower the base more, the whole toilet moves more into the center of the head because of the turn of the hull in the head. There is a new vent hose that runs up the head inside the port wall and we added a clamshell vent outside just forward of the head port.