My family and now just my dear wife and I have been sailing and dealing with my IC for well over 30 years onboard. Being in Port (harbor) is a bit difficult, but not impossible as most male shorts can be large enough to cover, add a baggy shirt and it all works.
Have used cloth diapers the vast majority of time. Washing while underway, the name escapes me at the movement, but it is a can of size with openings and fins that causes it to spin. Attach it to a dock line and drag it behind the sailboat works great. Drying under way is fast and also easy as one simply attach the diapers to the out-haul line that runs along the boom. The combination of being underway, natural wind and a fast drying time. Most all marines have a laundry and that handles things while in port.
Enjoying life onboard a sailboat is commonly 15 to 25 miles out in the Great Lakes where the powerboats are very near the shoreline to maybe 5 miles out.