6 or 12 Gl water heater

[B_Hunter45]

Hi All,
My 8 Gl Kumma water heater leaks and need replacement.
Raritan is my preferred option. They have 6 or 12. The 12 will require some additional work in fitting.

From your experience what is more suitable for coastal cruising?
The 6 will heat faster but have less hot water. When heated by the motor the extra 6 Gl might be a blessing, but we usually motor very little.

Usually we are 3 on board.
Thanks

[Scott Berg]

1) you'll be happier with the larger model
2) you can add a much larger element (we have a 3500watt one) if your electrical system will permit you to and that gives you much faster reload time (perhaps even continuous hot water)
3) look at Torrid; they make the best units on the industry and are very flexible with their options

[B_Hunter45]

Thanks Scott,
Actually we are limited to power since we anchor most of the time. so 1500Watts is our top element.

[a64pilot]

Go for the bigger one, it will stay hot longer, plus even when it cools quite a bit you can then use just straight hot water, and you have twice as much

[CaptTom]

Do you run a genset or just solar?

To me, the best argument for a higher-wattage element is if you're anchored and using a genset. That's when it's most important to minimize how long it takes to heat up the water. Who wants to run a noisemaker any longer than necessary?

Obviously, the opposite applies for solar. And if you're using shore power, it probably doesn't matter how long it takes.

[akprb]

6

It encourages the proper shipboard behavior ;-)

No-brainer

[Cheechako]

Well, if you really dont run the motor much, maybe 6 gallon as it will heat up faster. I liked 11 , but motored quite a bit. I wonder if another brand has a size that is bigger than 6 but will fit your space?

[mvmojo]

I'm a fan of the 6 gal units - fast heat up time when running the genset. We set the thermostat fairly high and have plenty of water for the two of us to take back to back hot (not just warm) showers. I think the key is a high thermostat setting (130+ degrees F) so you're using less hot water and more cold. If worried about scalding, put a mixing valve on the water heater itself and limit the temp to something you're comfortable with, like 101 degrees or so.

[Pete17C]

Do they make direct fired tankless water heaters for boats? If you have propane already, I't be an easy swap. You could even get a coil and fan and use it for heat.

They are all the rage for residential installs now. Like 98% efficiency.

[Tony Tommasello]

After purchasing a 2001 Catalina 42MKII the 10 gallon water heater leaked and needed replacement. The access door was too small and rather than spend time and money on carpentry I disassembled the heater, basically removing the stainless box getting to the aluminum tank that fit through the access panel. I replaced it with a 6 gallon tank that fit the access door (stainless box and all) and have not missed the additional 4 gallons.

Capt Tony.

[mvmojo]

Originally Posted by Pete17C

Do they make direct fired tankless water heaters for boats? If you have propane already, I't be an easy swap. You could even get a coil and fan and use it for heat.

They are all the rage for residential installs now. Like 98% efficiency.

Dangerous on a boat in small enclosed space... there was a lady in Annapolis a number of years ago who died while showering due to a poorly vented propane instant hot water heater. Not saying they can't be made safe, but there is an added risk associated with them.

[waterman46]

We have the boat's original (1983) 5 gallon hot water heater and it's been just fine for 2 adults and one child. Daily shower for 3 people, and it still has enough heat left for the second day if we didn't run the generator or engine. Heats from cold start to very hot in 15 minutes. The water gets so hot that when showering you use very little after mixing it with the cold water (and I like very hot showers). I am also the dish-washer on our boat, and I use hot water each time.

I should mention that we each use no more than 2 gallons of water for a shower. It's plenty. Since the mix is probably 1/4 of that from the heater and the rest is cold water, why would we need a larger heater?

If you need more hot water on rare occasion, just fire up gen or engine and you'll have it in 10 or 15 minutes.

[waterman46]

Originally Posted by CaptTom

Do you run a genset or just solar?

To me, the best argument for a higher-wattage element is if you're anchored and using a genset. That's when it's most important to minimize how long it takes to heat up the water. Who wants to run a noisemaker any longer than necessary?

Obviously, the opposite applies for solar. And if you're using shore power, it probably doesn't matter how long it takes.

Gensets usually need to run long enough to charge batteries, anyway, so any hot water heater is easily up to temperature long before batteries are charged.

I would think that power requirement of most any hot water heater is far beyond the limits of power available from nearly any solar installation on a boat, especially if you need to charge batteries also.

[Pete17C]

Originally Posted by mvmojo

Dangerous on a boat in small enclosed space... there was a lady in Annapolis a number of years ago who died while showering due to a poorly vented propane instant hot water heater. Not saying they can't be made safe, but there is an added risk associated with them.

Propane is used on many boats even though it's inherent dangers are well known.

I would say if unmitigated safety is your goal, sailing/living aboard may not be for you.

[Olly75]

Fit a thermostatic mixer at the tank and your hot water will last much longer. You can also turn it down to really stretch out the tank.