These units have failed to catch on, even ashore, with the most ardent eco-freeks. hint, hint. One of the problems you are going to have, other than the fact that cooking manure stinks until completely dry, is that a boat moves about and that is not the best way to produce compost effectively. I think the biggest drawback you are going to find is the smell. If you thought your head smelled before just wait 'till you start cooking piss and s***. I am sure the manufacturer will tell you this will be no problem. I am equally sure that it will be. I was on the first merchant ships to have sewage treatment and the learning curve was odiferously painful. I'm not sure you understand how much juice it's going to take either. Reread Cam's post. It's gonna take alot of energy to make it so your s*** doesn't stink. A solar panel is not the answer.
Lastly, after you are done testing this marvel of engineering, which i remind you they cannot give away ashore, you will have approximately zero chance of selling it to another boater, unless you know Al Gore. From what I understand, he'll buy anything.
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.