Re: Historical question: toilet on small yacht?
Wilcox Critenden was making marine toilets very much the same as those today, nearly 100 years ago. Repairs could be made with bits of leather and flax packing and they only took a couple of pumps on the 2.5' handle to clear the bowl and lines; very efficient.
Unfortunately, if you build a relatively maintenance free, reliable product, you can't stay in business and they are long gone, though the lucky few who have them know what an excellent marine toilet they are.
"Any idiot can make a boat go; it takes a sailor to stop one." Spike Africa aboard the schooner Wanderer in Sausalito, Ca. 1964.