Getting back to the original questions -
Here is some information on hot water for your boat. I am not relating these to you as facts, but as my opinions to do with as you like. You can research
the accuracy yourself. It's your boat, you decide.
Fist on solar hot water, I purchased two of the Heliatos Solar collectors, the marine grade ones. I have not had them long enough to say how well they will hold up. I would say they are impressive, and made well. I have two, 2 X 2 foot panels
. One would probably do in the tropics. A small pump circulates the water, and is powered off a small 10W solar panel making the system rather automatic in operation. You do need some space for the panels
I have them connected to a 12 gallon Solaris water heater. Solaris makes many sizes. The tank material is copper. I know of no other manufacture that uses copper. Do a little research
and you might come to the same conclusion I did, copper rocks. It is expensive, and most will not want to pay for it. Mine has two heat exchangers in it, one for the engine, and one for the solar collectors. The water in it can also be heated with the generator
or shore power
, via a heating
For those that have the budget
this is a nice system of high quality components.
I would say you could easily get the same results with a coil of black PVC of your own making for less money
On making a fiberglass
hot water tank, sure, but it might cost you more than you think, and I'm not sure I'd want to drink out of it. Epoxy
, some 1708 fiberglass
cloth, some core
, and you can make some strong tanks
that will outlast the boat. I've made diesel tanks
, holding tanks and even some water tanks from the above. It is not difficult once you have some practice. Trouble is, there are some skills that you have to acquire, and the materials are not cheap
or readably available to the public. Then you may not want to use epoxy
, as it does not perform as well when it is heated to the high temperatures one might see in a marine water heater. You could use Vinylester resin; some are formulated for quite high temperatures. Trouble is, when constructing potable water tanks there are even more things to be aware of, and precautions to take. West Systems have some recommendations about how to go about it, but don't endorse it because they can't control the outcome. I don't think they would want you to build a hot water heater using West epoxy. All-in-all, unless you were doing it to fit a strange space that a purchased water heater would not fit, I'd say don't bother.
Now, about the propane flash heaters. I used a Wolter 300 for eight years. That included several showers a day, dishes, and more. It worked flawlessly and was more than up to the job despite its diminutive size of not much bigger than a lunch box. A 20 lb bottle of propane lasted at least three months with two full time liveaboards bathing, cooking
, and more. We often had guest too. This was a real convenience and removed the camping aboard feeling of the typical boat. It was installed in a cockpit
locker and had a flue that vented overboard
As to ABYC, well, just like the many requirements/inspections that any home built in the US requires, their recommendations fail to protect boat buyers from much at all. You must understand that they are just that, recommendations, and boat builders are not required to follow them. Boats have few mandated requirements at all, until you get into inspected vessels carrying passengers for hire. So, we end up with a mess, since boat builders do what they want, and buyers get stuck with their crap. To be fair, they have improved. The boat builders that is. I bought a new boat years back, thinking it would be built to good standards. I insured it, and it did not require any survey
since it was new. Years later I sold it, which did require a survey. I got hit with a list of things that were not compliant with ABYC. These I needed to fix. Thank you boat builder
, and thank you ABYC. Like buying
a home, you better be an informed consumer and do your own inspections, because the so called home inspectors and surveyors come in many varieties, some good and some bad. All seem to have outs in their contracts when you hire them for things they miss.
As far as to the validity to the ABYC requirements, well, I don't think the people there are stupid. They do however have opinions that everyone in the industry do not agree with, and they do seem to be going a bit overboard
, so to speak, with the amount and complexity of their rules. Oh, and if you'd like a set of their recommendations, be prepared to pay a hefty fee for them, thank you very much.
I don't think many boats are built where something in the ABYC requirements was not missed or not followed. It is the rare surveyor
that knows all the rules, or surveys a boat to the degree necessary to check the vessel for compliance to this "voluntary" set of recommendations. Each surveyor
seems to certainly have their pet peeves.
So much for ABYC, and if you see that I don't see them as the saving grace for the boat buying
and boat using public, well, you'd be right. We got by without them for decades, and boating
is one of the safest sports there is. There are very few deaths in any given year. More people die of from lightning
strikes, or tripping and falling.
Propane flash heaters for boats -
In a word, yes. Let's first look at them as to how they are used. Why does ABYC see them as an unattended device? This is stupid. It would be a very unwise person to turn on the propane system and leave it on unmonitored, for any reason. Who would leave their boat with it on? Who would leave it on when not using it? How is a stove used? You open the propane tank valve, turn on the propane solenoid, and use the stove. Hopefully, your system has a solenoid control panel
that has propane leak detection to shut off the gas if it detects a leak. Now, once you are finished cooking
, you shut off the solenoid, and turn off the valve at the propane tank. These are the same steps we took when using the flash water heater. The propane system was only turned on during use, while we were using it. Sure sounds like an attended device to me.
I do think flash heaters can be safely installed in boats, sometimes without supplied outside air, or vents for the flue gasses. Still, I think this is a bad idea and could, actually it did, lead to accidents and people being killed. That is precisely what drew a proverbial target onto the back of the flash heaters. It resulted in ABYC drafting rules that are nearly, but not impossible to meet. I do think the intent was to prevent them from gaining acceptance.
The gas stove gained acceptance because insurance
companies found that they had a better safety record
than the diesel and alcohol stoves they replaced. Not so with the flash water heaters. However, I think if you look into the accidents involving flash water heaters, you will find improperly installed and non vented heaters. One I know of was installed in a shower
in the head, and used in the winter with the boat closed up. The result was someone died.
I believe someone mentioned they knew of no approved flash heaters for boats. Really, well who would approve them? I am unaware of any equipment
being specifically approved by ABYC. That would be an enormous undertaking.
If you do want to install a flash heater, I do think you can do it meeting all ABYC recommendations. Some are a bit tricky, like it can't be in the engine room, it can't vent into the cockpit
, and it must be supplied with outside air.
One heater can meet these requirements, Precision Temp. It has powered venting and can be vented over quite a distance to the transom. It has a sealed combustion chamber and has a combustion air intake. However, you must create a shelf with the ducting for it to bring in the outside air. Not terribly difficult. So yes, this heater can be installed and meet the ABYC requirements, if you have the space and skills. Trouble is, this heater cost over a grand. One is installed on my boat and it was not terribly difficult. It is installed meeting all the ABYC recommendations. Of course, this does not mean every insurance company will insure a boat with a flash heater, even if it is installed per ABYC. You pays your money
and you takes your chances.
What if you want to do it for less than the pricy Precision Temp? I still think it can be done, and meet the recommendations. Buy one of the less expensive units that have venting. Install it into an enclosure that is airtight. Aluminum
would be a good choice for making such an enclosure. Bring in outside air via ducting to the bottom of the enclosure. Duct the exhaust
out the top and overboard. Be careful to follow manufacturers recommendation for the venting. Seal wiring
going in and out of the box. Make a removable cover on your box so you can service
it, and don't forget a gasket
. Simple, you've meet the requirements. Hold on, not so fast. The Precision Temp was designed with power venting and a sealed combustion chamber. It has many safety interlocks. Your home brewed system better be well designed, especially the venting, to ensure it works properly, and this might mean you need to bring in the air via power venting. You might want to use a Murphy temperature gauge, so you could interrupt the gas solenoid if your enclosure gets too warm (like the heater had a problem). Murphy gauges have a set of contacts that open at a user settable point. So it could be done, not so difficult really.
Or.....you could just do like many, install what you want, how you want, and don't ask and don't tell. Life is full of risk, who can say what risk is too much for you. Certainly not I, but you sure will get an earful around here if you talk about it much.
Finally, I disagree with the guy that says no flash heater has been made that can meet the requirements. In his mind yes, not so if one follows recommendations carefully, and get creative doing the install. Hogwash to the naysayer! Fact is, you could install it underwater, hanging off the keel
, and someone would still say it's unsafe. Makes you wonder how man had the courage to invent the wheel
some 5000 years ago.