Another vote to keep it simple.
Contractor bucket (sold at home depot)
Toilet lid made to snap on bucket (eBay, amazon)
Roll of 13 gallon kitchen garbage sacks
Roll of paper towels (or puppy pads)
Bag in bucket, a couple paper towels in bucket, do your business, tie knot in bag, double bag, tie second knot in second bag, store bag in bucket.
No mess, no smell, no clean up, nothing to break, ever!, no worries about a guest flushing something that will break or clog the head, no heavy job to haul off the boat like a poripott is, no embarrassment, no nothing! Throw the sack in the kitchen garbage sac when you leave the boat and the dumpster is at the end of the dock. Finished!
My last boat came with a high dollar head, a sears made self contained job. I instructed my other half to throw it away, we did not want to mess with it. It hit the dumpster.
Our boat has two heads, one in the main cabin, and one in the aft cabin. Why not? They do not cost anything and no Maintance or clean up. Aft cabin is built into the port bunk. So is a sink next to it. Never know it was there unless it is needed.
