Hot Water

[CHB RON]

Just bought a 35" CHB and the previous owner took out the water heater. I need to install a water heater. Any recommendations or thoughts? I have no generator in the boat so how do I heat water when away from the dock? Is there such a thing as a water heater that house batteries can operate?

 

[Adelaide]

Just bought a 35" CHB and the previous owner took out the water heater. I need to install a water heater. Any recommendations or thoughts? I have no generator in the boat so how do I heat water when away from the dock? Is there such a thing as a water heater that house batteries can operate?

This is the water heater I have. It operates off of 110 and also the engine, when it's running. The hot water stays hot all day, even after I turn off the engine. I can't say enough good things about the Isotherm.
Isotherm Electric Hot Water System with Engine Heat Exchanger

 

[bshanafelt]

We use a propane point of use/on-demand water heater. As we already have propane aboard, we have the requisite lpg safety equipment.

The water heater has a number of redundant safeties built in as well including water flow sensors, flame sensors, monoxide sensors etc.

As we regularly anchor out for multiple days at a time, have no generator on board but have a very large house bank, this works quite well for us.

 

[FlyWright]

Atwood Water Heater 11 Gallon 110V - Star Marine Depot

This is very similar to what we have onboard. Heat comes electrically from shore power or Honda generator or from the stbd coolant through the heat exchanger while the stbd engine is running.

 

[Bay Pelican]

Give some thought to your use of the boat before you buy the water heater. Pure electric works well if you marina hop. If you anchor infrequently, or just as travel stops than an electric unit which also is heated by the main engine works well as the water will be heated each day while traveling. If you plan on anchoring for days or weeks at a time in one location you have a couple of choices. You can use the generator's electric output to heat the water when you charge the batteries. This is the normal setup for a cruising boat. However, if you see that your generator will be overloaded from battery charging and other household needs, then water heaters with two engine connections are available so that both the main engine and the generator can heat the water when operating. Thus the electrical output of the generator can be reserved for battery charging.

We have an 8kw generator and use it to run two large (125 amp) chargers as well as teapots etc. When we add the water heater (1200 watts) the generator is loaded as the hertz and voltage drop.

 

[FF]

There are many RV water heaters that operate on propane.

Very modest in size and hold plenty for a couple of showers , a dishwasher or wash load.

The have a 120 element , so work fine at the dock or with a noisemaker.

 

[CaptTom]

You won't heat water with a battery bank that will fit on any reasonably sized boat.

There are other options, like solar heaters or just a black shower bag hung on deck.

With no built-in genset on our last boat, we'd run the main once or twice a day to heat water and charge up the house bank. The water heater loop from the engine jacket water is a great thing. I upgraded to an 11-gallon tank (from the original 6-gallon), but frankly it didn't make a huge difference, we got a lot of use out of that 6-gallon unit for years.

 

[CHB RON]

Thanks for all the input. 2 questions come to mind, if I go electric should I get a 6 gallon or a 11 gallon tank and two, if I consider propane, I've never seen a propane heater for sale. Does anyone know the source of a propane heater?

 

[skipperdude]

Most likley you can find them at an RV shop. Like for motorhomes.

SD

 

[Adelaide]

Thanks for all the input. 2 questions come to mind, if I go electric should I get a 6 gallon or a 11 gallon tank and two, if I consider propane, I've never seen a propane heater for sale. Does anyone know the source of a propane heater?

Do you take showers on your boat? Or is hot water only used for dishes, washing hands etc?

 

[markpierce]

Mine heats using the engine or hooked up to 110V. No genset, so relying on batteries would suck them "dry." Since I overnight at marinas or anchor out rarely more than two nights at a time, the hot-water limitation isn't burdensome.

My heater is a "box." The silver one, pictured here still wearing the builder's blue protective covering, next to the white house-battery box and adjacent to air tank and compressor:

 

[CHB RON]

Yes, I want the water heater for showers.

 

[psneeld]

You won't heat water with a battery bank that will fit on any reasonably sized boat.

There are other options, like solar heaters or just a black shower bag hung on deck.

With no built-in genset on our last boat, we'd run the main once or twice a day to heat water and charge up the house bank. The water heater loop from the engine jacket water is a great thing. I upgraded to an 11-gallon tank (from the original 6-gallon), but frankly it didn't make a huge difference, we got a lot of use out of that 6-gallon unit for years.

1500 watt element powered by 12 V DC inverter....200 amps times 20 minutes (1/3 hr) is about 70 amp hours...which is about 1/3 of a 4 golf cart battery bank. feel free to shoot the math as I haven't done it yet but seems within reach of a typical trawler...granted you have to start charging right away...but underway...you may arrive with full batteries and hot water if only taking one shower.

 

[FF]

Propane RV Water Heater - PPL Motor Homes

Shop around most will be about $300 or so and there are many mfg.

If you are willing to have propane aboard for a range and Hw heater , why not go all the way and install a propane fridge/freezer too?

30 days of silent refrigeration on a 20# tank.

Beats dead batteries , 4 hour charge noise , and is almost zero maint.

 

[CaptTom]

I've had a 6-gallon and 11-gallon. You don't really get twice as much hot water with the bigger tank. The hot water coming out the top is replaced by cold water coming in the bottom. The longer they have to mix, the cooler the output is. So with both sizes you have a lot of hot water for a short time, or warm water for a long time. The 11-G will be a little warmer, a little longer.

 

[FF]

Space concerns keep all these devices (and reefers too ) with minimal insulation.

A simple wrap with house store fiberglass will add considerably to hold time at minor cost.

 

[Peter B]

Just bought a 35" CHB and the previous owner took out the water heater. I need to install a water heater. Any recommendations or thoughts? I have no generator in the boat so how do I heat water when away from the dock? Is there such a thing as a water heater that house batteries can operate?

Ron, Adelaide gave you the best answer. I have a similar boat to you, and I do not have a generator either, if you don't count the wind genny, so I replaced an old worn out heat exchanger type cylinder with no element for electricity with one of the Isotherms as in the link, and it also connects to the engine coolant circulation. It works a treat while out and we are running the engine moving anchorages, but when at the dock I do connect it to the shore power (in our case 240vAC), for a quick pre-heat while we are preparing to leave, then engine running is enough to keep it hot enough to have showers, wash dishes etc, with no problems.. I recommend putting in the largest one which will fit - in our case it is 42 litres, = ~ 11gal. I don't connect it when we are away from the boat when it is berthed. the only thing I leave on shore power in that situation is a battery charger.

http://www.outbackmarine.com.au/Isotherm-Electric-Hot-Water-System-with-Engine-Heat-Exchanger.2768

 

[CHB RON]

Water Heater

Thanks for all the input, it really helped. I bought the recommended Isotherm unit and am having it installed Thursday. Thanks again for the input.
CHB RON

 

[Codger2]

Just bought a 35" CHB .........

Thought you might want to see a CHB 45 in S.E. Alaska. I saw this boat and talked to her skipper July 22nd of this year.