Poor man's electric head
A prior boat of mine (1980 H30) had a poor man's electric head installed by the previous owner. The discharge hose from the manual head fed directly to a macerator which then dumped into a small holding tank/bladder. To flush the toilet, you simply pushed a momentary button that activated the macerator and "swoosh" or should I say "flush" and the bowl was empty. We used fresh water from a gallon jug to fill the bowl - with deodorant added - and never had the sulfur smell from sea water in the hoses.