On my cruising boats I’ve always opted for conventional flushing marine toilets in conjunction with a holding tank. On my earlier cruising boat there was a Y-valve to allow waste to be directed to the holding tank or discharged directly overboard, on my later boat all waste went via the holding tank to a dockside pump-out facility or overboard.
These systems were quite satisfactory and I never felt the need to seek alternatives such as on-board waste treatment systems with their complex macerating and chemical treatment paraphernalia.
I did once have a VacuFlush system on a power boat I owned and it was the nearest thing to a home loo I’ve seen on a boat. Step on the foot pedal and whoosh, away it all went. But it used fresh water for flushing and was battery operated thereby consuming two essential resources which excluded it as an option for long term cruising.
A composting toilet is something I’d always thought of as the ideal choice for a cabin in the wilderness rather than on a boat but a couple of years ago I came across this article:
It’s a very informative and appropriately lavatorial discourse on the installation of a composting toilet on a boat and makes a good case for such a choice. So, don’t pooh-pooh alternative toilets until you’ve sat down and read it.
Personally I’ll be sticking to my conventional hand flushed marine toilets but I do love the name of the device – the Air Head.