The two main uses are for washing dishes or having a shower, both activities I am likely to perform during overnight trips on DiveCat. As previously documented, fitting a gas califont for heating the water has proved to be unviable. Luckily, there are now numerous 12-volt water cylinders available thanks to the booming RV market, so I had a wide choice of options to choose from.
These units operate in a similar manner to a domestic hot water cylinder, although they operate off 12VDC battery power rather than 220VAC mains power. The lower voltage limits their heating capacity and therefore also their water volume.
If your boat has an inboard engine, then it is possible to capture some of the engine heat through a heat exchanger and improve the thermal efficiency. In fact, many 12V units already include the internal piping for a heat exchanger
