Bianka had an on demand Paloma hot water heater installed when I bought her. This came in very handy when I was living on board while I was working in New York City. I was working an overnight shift at the time and taking a shower at 11:30 at night in April with unlimited hot water was a luxury found on few sailboats. Today I usually rely on a solar heated shower or a fresh water rinse off from a five gallon bucket I keep on the stern for after a swim. I have not had to use the Paloma hot water heater for several years. Like many things on the boat it will have to be replaced at some point whether I use it or not. But, when that point comes I might consider something like this:
It's a Coleman Hot Water On Demand Portable Heater. I can see this having several advantages as a replacement for an installed hot water heating system on a boat. For example it's portability. It could be used in the cockpit on long voyages by the helmsman to make a hot beverage while underway without leaving the helm or disturbing sleeping crew members. It has an optional shower hose and can be turned into a portable on demand hot shower. It can also be connected to the on board propane system or use Coleman portable canisters. The water intake can be plumbed into the on board water system. It could also be taken off the boat and be used at home should some natural disaster knock out power and the ability to take hot showers at the house. Other than making sure that the unit is used with proper ventilation. I see a lot of things to recommend this unit on sailboats of all sizes. Watch the demo video and see if you don't agree. The retail price tag of $250.00 is another real good reason it would make a good replacement.