I was rereading my notes from last season and was reminded of a question that came up. We have done a lot motoring along French canals in hire boats. They all had diesel-fired water
heaters. Universally the water
would stay hot enough that we could have a warm to hot shower
the next morning without firing up the engine
again. But none of the sailboats we chartered this season (in the PNW) provided more than tepid water after any significant time had past.
How do the hot water tanks
on a typical sailboat work? I do know the after berth above the water heater benefited from the heat produced, but the insulation
didn't seem to be there to keep the water hot. Is it a matter of size? The canal boats tended to be 40-50 ft. I will say the water was generally way hotter on the sailboat after the motor
was shut off: hot enough to melt a plastic pop bottle. Never had that problem in France
. So probably completely different systems...
So what does one need to know about hot water on board?