My father's boat had only thru hull cockit scuppers, and no thru hull for drains or heads. The "head" was a galvanized bucket under a wooden round seat (not the most comfortable) in a wooden box which also served as a seat for dinner in the cabin on my father's 26' sailboat. The bucket was emptied at sea on the way home, or if staying for some time, then the dinghy rowed to 3 miles off Catalina, was used to dump the bucket.
The only head in the C Dorys I have owned which I did not like was the 2003 C Dory 25, which had a Jabsco manual marine head in the bathroom, but the 20 gallon holding tank was way back under the splashwell, with a macorator pump overboard or a suction tube for a land based pump out. It was a real problem if the electric macerator pump went out--as it did in AK, where finding another macerator pump or a rebuild kit was not readily available. We had to have a guest bring a new pump from West Marine in USA mainland.
In the second, 2007 C Dory 25 the boat had an airhead, which I felt was the best solution--problem is difficult to use an AirHead in a C Dory 22. Our 22's both had portipotties. I have a 3" direct sewer connection for my RV Pad at home, as well as a bathroom which directly enters from the outside of the house as well as inside (for swimming pool use), so pouring the content of the portipotty was not a problem. Lake powell has SS sinks for pouring out the content of the Portipotty at Lake Powell, and other places such as Catalina, offshore in both East and West Coast was go 3 miles to sea and pour overboard. The C Dory 255 Tom Cat had the self contained Sea Land Commode with 9 gallon holding tank in the base, with "Y" valve to pump out or Macerator overboard discharge. In some no discharge zones, the thru hull manual overboard discharge had to be disconnected--not even a locking "Y" valve does not fulfill the regulatons in those No Discharge zones.
After the experience with the bad macerator pump, I carried a rebuild kit and another new/rebuilt Macerator in my "spares". Same for pressure water system, as well as keeping the foot pump, "just in case". I learned very quickly that the water pump was most likely to fail when Marie was in the shower! With quick disconnect on the water and powere, I could get a second pump working in a couple of minutes...Happy wife!