Electric Shower

[Nowhere-Man]

I am working flat out on the boat. I have the job of fitting a shower. I built the shower tray last year and I decided not to use gas. I want to use electric but bear in mind shoreline hook-up is limited to 3 Kilowatts. Most showers are twice that. Even the electric shower head system is around 5 kilowatts.
I can get a hot hand-wash unit for free and theoretically it would work as a hot trickle. The pump pressure may drag, though. I feel my best bet is a thermostat controlled water tank.
This boat (according to an article) only ever had a foot pump for water in a small sink. No actual pipes. What's amusing too is my shower will only work if you bend your knees. As it is I keep bumping my head on the ceiling but with the shower tray you'd never be able to stand up straight. Were people short in 1971?
Someone said Screwfix has some low wattage shower systems.

[ppppenguin]

You can't avoid the laws of physics. You need certain amount of power to heat a given amount of water to a given temperature in a given amount of time. The sums are easy enough once you've you've looked up the specific heat capacity of water. The result also depends on how cold the water is to start with. However I can tell you from experience that a 7kW electric shower is a pretty dismal thing. Not much more than a little squirt of really hot water or a somewhat better flow of lukewarm water. The 9kW and 10kW ones are a bit better. If you want a hot shower with a decent flow of water you really need 20kW+, something you can't really do with electric showers. Combi gas boilers usually give at least 20kW and so can give decent showers.

Of course if you can heat your water in advance of having a shower then you can do it with much less power, just takes longer. This is how traditional stored domestic hot water systems work.

[Crackle]

You need a hot water tank or calorifier. https://www.asap-supplies.com/domestic-w...alorifiers.
This can make use the free hot water from the engine whilst it is running. ( if it has a fresh water circulation system with thermostat and heat exchanger, I dont think raw water cooled engines work quite so well with these calorifiers. Probably not possible with an outboard) The calorifier also has a 1KW immersion heater, so it only draws about 5 amps, well within the capabilities of any marina power supply.
It will heat the water in the tank up slowly so you can have a limited supply of piping hot water.

Mike

[Mark Hennessy]

Thread moved to a more appropriate section...