The Crown Head is a great toilet--an all but indestructable workhorse...one of the first macerating electric toilet, introduced by Raritan in 1968. It's the only toilet I'd recommend for use on a "Deadliest Catch" fishing trawler or a tug in NY harbor. But advances in toilet technology have turned it into a dinosaur for the recreational boat market. Today there are a dozen toilets--several of which are also Raritan products--that use less than half the power and water needed by the Crown and make a fraction of the noise. It just no longer makes sense to fill up holding tanks with flush water and drain batteries in a day without a generator.
For years, Raritan had what they called a Lower Unit Exchange Program, which swapped out a worn out "works" for a rebuilt one...the price was about $350 in the 1990s. Then, in 1991 or '92 they introduced the SeaEra, which is what really turned the Crown into a dinosaur. Raritan recognized that and began offering the SeaEra "conversion" as an exchange unit for worn out Crowns (and may still do that)...and had a lot of takers. But there were--and still are--just enough "old farts" for whom the Crown Head is the ONLY head to keep it in production.
The Crown II was developed in response to those who wanted a dinosaur that uses pressurized fresh water...it does make considerably less noise, but that's the only thing to recommend it...the sea water version requires a separate remote intake pump.
And now y'all know more about the Crown Head than you prob'ly wanted to know.
Hope you're enjoying a safe and happy 4th!