Hi Dick, I grew up sailing, as you did, in the days before holding tanks and Y-valves, where heads flushed directly into the water. OK at sea, but a problem in congested waters. Holding tanks and Y-valves were a quick fix, clumsy add-on, yet acceptable solution. I've never liked the holding tank idea and its ever-present odor so I was open to a better idea and I think the composting head is an improvement. It is classified as a self-contained (type II) head by the US coast guard.
Keeping the solids and liquids separate eliminates the nasty odor (NASA separates on the space station and shuttle). Since urine is sterile it really can be dumped anywhere. We usually try to empty the 2gal container (discreetly carried in a canvaas bag) into shore based tiolets when available. The "solids", which have a not-so-disagreeable organic peatmossy odor, can be emptied into a garbage bag and put in a dumpster, just like kitty litter, but way less smelly. ("must be some big cats on that boat"). If one is cruising a wilderness coastal area (away from dumpsters, toilets, pump-outs or "off-shore" facilities) one could bury composted solid contents on land. I suppose you could dump it overboard when offshore for extended periods. I think I would just use the bucket & chuck-it method in that case. This is where I think the traditional head would be preferable.
I was sold on the idea by a couple who converted several years ago. They cruise for 6 straight weeks every summer, far from pump-out facilities on the wilderness north shore of Lake Superior and then part-time the rest of the summer in more "civilized" parts of the lake. They empty the solids once per season. I'm sure they use shore facilities when convenient, as anyone with a holding tank might. Testamonials say 2 people can use it daily for 6-8 weeks before having to empty the compost. That's longer than one can go without pumping out a holding tank. It can last longer if it gets time to decompose between uses, so using shore facilities when available helps. It also can be "freshened" up by adding more petmoss if it gets a lot of use. We had four of us using it daily on a recent four-day sail and the composter was over whelmed and had some odor (usually there is none), although I suspect it was due to someone using about a half roll of paper. One could also empty the composter into a second container to be emptied later--kind of like carrying a holding tank. Once a holding tank is full, that's it until you can pump it out.
Some other pluses (other than eliminating the odor) is there's no unpleasant head maintainance/rebuilds/uncloggings, frees up storage space, no cost or hassle of pump-outs--you're self sufficient and not restricted in how far you can sail away from the nearest pump-out station.
I have a plumber friend who sails with me and said if he ever built a new house he would install composting toilets and aviod the expense and problems associated with the plumbing, septic/sewer etc. He's also a gardener, so...
I know it sounds like I'm a salesman for the company, but I have no connection. It's not perfect but for me the pros outweigh the cons. Simplicity, self suficiency and no odor.
