Marine Hot Water Heater.

[Alasgun]

I have seen all the post's relating to the use of generators versus inverters during the creation of hot water. Both seem to have some merit as well as downfalls in my opinion. My question is this, has anyone had any experience with the tankless on demand models, many of which are advertized for marine service. Yes, you have to have propane to support them but they are generally smaller and weigh less than the full electric models. They also seem to weigh less and take up less space than either the inverter or generator method. Soliciting your opinions, Mike on Huda Thunkit.

[Larry H]

At least one of the companies (Wolter)building 'marine tankless water heaters' has gone out of the marine business due to CARBON MONOXIDE POISONING.

These propane water heaters must be installed completely outside of living spaces so that the exhaust cannot blow back into the boat.

[thataway]

The tankless propane heaters are used both in homes, apartments and many boats in Europe. When these were introduced into the US in any number (1970's), there were a number of deaths and other problems with carbon monoxide. There are some propane heaters which are reasonably safe in boats. However a C Dory would not be an appropiate boat (lack of room in the head is one reason). If I buy a Tom Cat 255, I may get a tankless 110 V water heater, rather than the 6 gallon tank type. The tankless will heat faster, have adequate heat rise, weight less and not carry the extra 50 lbs of unusable water weight around in the boat. These 110 supplimentary heaters are a common object in the big box hardware stores.

[Captains Cat]

Another contradiction in terms!

"Marine Hot Water Heater"

If it's "Hot", why would one want to heat it?

OK, OK, I knew what you meant, it's just always bugged me...

Charlie

[Discovery]

Thataway

I looked at the 110 V. tankless water heaters to put on Discovery. The advertised temp. gain was only 20 degrees F. That still left the water too cold for a shower, if the water in the tank started out at 50 degrees F. or less. We went with the factory 6 gal. model and will take along the Honda Gen.

There were larger tankless models that heated more, but required 240 V., and won't work on 30A shore power or with a small Honda gen.

Brent

[El and Bill]

We use a backpacking solar water heater and it's great. Folds up to nothing in size, water gets too hot if you aren't careful, no power demand -- simple and easy.

[JamesTXSD]

We have a tankless water heater in our Texas home and LOVE it - an endless supply of hot (as hot as you want) water. The problem with this type of install in a C-Dory is the tremendous demand for electricity; ours uses 4-40 amp breakers in our home. I don't think the 30 amp shore power or a Honda 2000 generator is up to the task. The company that makes our residential model has some smaller units... I'll check into that and report back. I did visit with Scott from the factory regarding a tankless water heater in our 25; he did say that he'd check into it.

And on our sailboats, solar showers have worked fine... until you want to shower first thing in the morning or on a heavy overcast day. I really think this will be a part of our water usage, too. We also use a Zodi (propane fired) water heater on the boat - NOT in the cabin, though.

Options to consider.

Best wishes,
Jim B

[Byrdman]

Mike, you hit the nail right on the head with all having their own merits and downfalls. I have the 6 gal Seaward water heater on FreeByrd. Les designed the whole electrical system around an on board AC unit, the hot water heater, MY coffee percolator, and hair dryer for Sherryl. Things change... Not all the parts for AC vents were available in Dec 2003, so, we jointly made the call to just send all the AC parts back rather than me attempting a "half-way" thru the project installation. I have been happy with our decision on that call. And, to date, I still do not have a generator, but do have one of those big ol yellow dock addictive cords... The "cold water" gets hot in a matter of minutes...and not many of them once the juice is applied....and it stays warm for hours too. Bill and El have a great no-power simple to use and store system too...if the sun is shining...
My downfalls: Give up a little room under the sink... which has proven to be no problem, so not really a down fall.
Weight:.... only 6 gallons....again.... no significant difference particuarly if you are in the cruising mode and have all kinds of extra weight on your boat for cruise mode.... no problem
POWER: Well, with no gen on board, on one occasion, I had to plug up the cord for the time it took me to go up and pay for fuel and get ice and stuff at a marina.... prior to me being able to take my hot shower.....again...not that big of deal. Most marina's will gladly give you a temp slot for a few minutes...at no charge, particuarly if you are dropping cash for fuel and stuff in their store. They are there to make a living....not be an indigent care facility.
MERITS: They are endless.... and an added safety advantage when washing dishes with real hot water as to avoid the things that happen if you do not properly wash dishes.....with hot water. And I love to cook so this is large for me. There is nothing like being able to swing on the hook, kick up the tunes from the satelite radio, climb out there on that swim platform between the motors... get sqeeeeaky clean...then just sit and watch the moor rise and the stars with a nice sun downer.

One of the best gifts I think I have been able to give was when George and Penny on Wanderer were traveling the Cumberland River system and Penny was able to wash her hair with HOT water on the 3rd morning. You'd thought I gave that lady the moon. ....and she did not even take advantage of the full body shower!!!

Hands down on a re-do, I'd put the exact same system back in a boat... as I think Dixie and Brent did on their new boat.

[willhave1day]

I have been researching water heat and cabin heat as one in the same around (getting my ducks in a row for that purchase even if it isn't next year like I hope!).

I have ideas for a diesel water heater, and a water tank with a heat exchanger and 110v coils (the kind you can plumb in your motor coolant if you had an inboard). I like the idea of Diesel rather than extra gas or even propane. Going this route, I can use the hot water to also heat the cabin while under-way, have hot water when there's no electricity, and just use a larger diesel can to share with the wallas. Or if there's shore power, I can "reverse" heat with electricity, and still have cabin heat and hot water.

It would be for a CD25.

I think I could squeeze it under the sink to share the wallas exhaust and fuel. More realistically I think it may need to go where the water heater is behind the dinette which would require 2 diesel cans, and a second exhaust.
But to those of you that own one..is the is a crazy idea?

[Sea Wolf]

willhave1day-

No, such ideas are not unrealistic or impractical from the get-go.

A lot of what would be possible would depend on:

1. The available heating and other units available commerically ready to go.

2. Modifications you could make to adapt them to your specific uses.

3. How they could be integrated to perform all desired functions.

4. Space available considerations in the boat.

5. And some thoughtful reflection on the KISS Principle, and whether a good gas generator and using an all electric appliance approach to the various tasks would in the long run be a lot simpler to design, implement, and carry the fuel for, since you could just tap into the main gast tanks with the generator.

I've got a Wedgewood propane 3 burner cooking stove, a Force 10 Cozy Cabin Propane Heater, and now a Honda 1000iea generator, which I'm presently tying into the main gas tanks. I also have an electric heater and system for dockside use, and few electric apliances like a fan, and even a mircrowave on the ready in the garage.

Things are getting a bit complicated. It's my guess that a generator / electric system would be simpler, lighter, cheaper, and easier to design, build, and maintain than a multi-source energy system with the requisite appliances.

Electric appliances are generally smaller, lighter, cheaper, more varried in functions available, and are also more easily removed and added from the cabin as seasonal and cruising requirements vary.

The biggest problem with the generator approach is finding a suitable mounting place on the boat (usually the cockpit) which will not interfere with other uses, like fishing, and which will afford a safe mounting place in terms of carbon monoxide disbursement and the prevention of theft.

However, since it's your major energy source or powerplant, building and dedicating a platform and a lock box around it shouldn't be that much of a problem to overcome.

The biggest drawback of the generator / electric approach is probably the noise issue, but the new inverter style ones are very quiet, comparted to the older ones.

You also only need to run the generator when the batteries are down or when you're specifically using a big draw 120 v appliance. Then too, by adding an inverter, you can run the 120 v stuff off the batteries w/o starting the generator for at least a reasonable time.

If yoiu have an electric system, you'll also find the dockside use with shore power a simpler switch over than if you're using multiple soures of energy.

Most of the boat, including a refrigerator, can be run off of the 12 v house battery(s), and adding a few more of those can increase your quiet time between runnings to hours at a time. (I have four group 27's now, and have never hit the bottom of the "electrical barrel".

Another consideration: With the generator outside and the appliances smaller and inside, you also free up a lot of space under the cabinets for storage that would have gone into stoves, heater, converters, etc.

If I was a betting man, I'd bet you could design and build an electric system a lot easier and for a lesser cost than the multi-energy source approach, but who knows?


So by all means, please go ahead and see what you can come up with! It might just be possible to find a simple elegant solution to all of these problems.

For those who can't stand the thought of all this stuff aboard a small boat, we'll offer the following:

How about a simple, Alaskan style cast iron wood / coal stove, some pots to heat water in, and a brass keroscene lantern? Certainly more ambiance in there there than in the putt-putt powerplant approach!

Let us know what you come up with! This stuff is fun to think about!!!

Joe.

[Ron on Meander]

For anyone considering a diesel water heater that can also be a cabin heater and be rigged for window defrost, check out the Hurricane Water heater by ITR. http://itrheat.com/newproducts1.html. I think it could probably be installed in the same place as the current electric water heater on my 25. I really like the idea, I just don't like the cost of it all. In the range of about 2.5 - 3 boat dollars.
Ron

[Sea Wolf]

Ron-

You're right about the expensive part.

Marine specific stuff costs a lot more, and having someone install it all at $90 an hour makes for a lot of pricey conveniences.

For $3000, I think one could get a generator, shore power, refrigerator, AC, miicrowave, hot water heater, big battery charger, inverter, and some other appliances if you got creative and frugal. Might just be a fun challenge.

Joe.

[thataway]

On the Cal 46 we cruised Alaska on for 3 years we had a Pro Heat truck diesel fired, hydronics (circulating hot water heater). This unit keeps the water at 150 degrees and is 45,000 BTU (way more than a C Dory can use). The major down side was the noise. Sort of like a jet engine, since the burner uses compressed air mixed with the fuel to give a clean burn.
I don't know what the noise level of the above mentioned unit would be. The amount of 12 power for one radiator and a small circulating pump would be a 2 to 4 amps--doable.

I would be leary of using a 110 V water heater to heat water enough thru the heat exchanger to give adequate heat. Some of the high end heaters are effecient--but most have only a blind loop, not coils for heat exchange from engines, so the amount of heat exchange out would be only a few hundred BTU, even though the water in the tank would be well heated.

One of the beauties of the C Dory is that it is KISS--

[drjohn71a]

Someone on this site had a photo of a quick connect line coming from an outboard.... Yami?..... with a note about the 'warm shower' line... I guess that would be a bit salty, but I wonder if there is a way to recirculate the warm outboard eflux into a heat exchanger...

I have friends who use one of those black solar bags tied to the cabin roof and they say it works even on cloudy days unless you're out in the winter cold.

There is nothing like being able to recycle the FWC heat cycle on an inboard into car-like heaters. I had a 110v/ engine heat water tank that was wonderful on my last inboard. As long as the engine could run, you had hot water, and the insulated tank would keep it hot a long time. I am hoping the Ranger R25 can be rigged that way.

John

[willhave1day]

Great advice. I think I can keep it realatively simple. http://www.eberspacher.com/hydronic4.php?section=waterheating

There's also the Webasto line at SureMarine.

About 7 lbs, 9 inches by 6 inches (if my millimeter conversion is correct).
Combine that with a heat exchanger water heater. I haven't found any US prices, but I'm guessing around $1,000, it's a bit more than getting a generator.
Obviously I have the time to dream big and see where it gets me! I wouldn't have a problem installing it myself. The generator cerainly is the KISS alternative but I've never been known to always do that

A month ago I stumbled across a diesel fired heater with a 6-15gallon capacity, built in heat exchanger meant for radiant heat and 110v alternative when on shore power. It was only a few inches larger than the standard water heater I saw in the 25 at the SBS so I could put this in it's place. The general fuel consuption I've seen is around .2gph also, as compared to 2-3lbs/hr for propane.
The holy grail, I am trying to find it again. It seemed exactly what I was looking for.