Saturday, March 5, 2016

Hot Water

I have been kicking this idea around for quite some some.  That is - a simple system to provide an adequate supply of hot water for showers, washing dishes etc, and for cooking as well.  However, we want simplicity and safety.

Since I have eliminated the possibility of us ever having a pressurized, on demand system that would require an electric pump, possibly a pressure tank, and a propane on demand hot water heater that frankly scares me the alternative is the simple act of heating water on the stove.

However, wielding around a big pot of hot water scares me too, especially as we get older.  We'll be heating water every day so the laws of chance may not be in our favor with regard to the possibility of a scalding accident.

So here is what I have come up with:

Autarkia will have a large galley.  There will be no shortage of counter space and we can accommodate a large, deep sink, a two burner propane stove with oven, a very large and well insulated ice box plus all the storage we could ever ask for.

So there is room to make a permanent crane/hot water pot assembly that can swing the pot over the big burner on the stove, over the sink, or over corner of the counter to fill the garden sprayer shower.  A locking pin could secure the pot in all three positions, or out of the way when not in use.  Pots are available ready to purchase with a spigot - and even a thermometer - that can be securely fixed to a gantry made with galvanized pipe.

I like it.


  1. Alan,

    Novel, simple, and cool approach if using propane.

    I've been thinking of two things:

    1. Years ago I met a guy who had a loop of galvanized pipe running through his fireplace and to numerous radiators in his house. That could somehow be adapted.

    2. One of my goals is to use solar as much as possible. Figuring out how to heat the water isn't very hard. Keeping it hot until needed is a different story. My theoretical solution so far? 5-gallon thermos, DIY of course. I've been stunned by the improvements in efficiency of thermoses over the years. The current thin stainless ones (often made in Japan) can literally keep liquids hot for days. I'm currently scratching my head for the simplest possible tank design that could simulate the properties of one of those thermoses (without glass vacuum). (Pg 3 has a cross-section of bottle)


  2. One afterthought related to your impressive design ...

    The combined height of the kitchen cabinet (yeah, no boat words ... sue me ;-) and the hot water pot might make lifting the cold fill water an issue as well. You could consider making a metal fill hose a permanent part of the gantry+pot assembly, connected to a flexible plastic tube, foot pump, and cold water supply container at floor level. Hope that's clear.

  3. I did not mention it but what I am planning is my cold water supply will be fed from a large water tank with a foot pump to a retractable hose at the sink. That can be used to fill the hot water reservoir, or the sink, or stretched right across the companionway to the tub/shower basin.

    Solar would be a great option if you have the sun. We get it here for a couple of months in the summer, otherwise not so reliable. But if you are in a sunny place then building a solar collector with black hose and some Lexan is easy. Your hot water storage unit could be built the same way you build an icebox... plywood epoxy and about six inches of styrofoam insulation. Build two, one for hot water and one for an icebox. Your hot water reservoir could then go anywhere you have the space, and could be as large as you want.

  4. I used an "on demand" propane fired water heater for years when I was in Greece back in the seventies. It worked just fine. I don't see the problem.

  5. Everitt, did you have some kind of pump or pressurization system? I'm looking to eliminate as much complexity as I can...would an on demand system work with a manual pump for example? Keeping an open mind here... :-) Also, I read in Reuel Parker's book that he would not have an on demand propane water heater that was not isolated in its own locker which casuses me some concern. Your thoughts?

    1. "I'm looking to eliminate as much complexity as I can...would an on demand system work with a manual pump for example?"

      I'll take your question for Everitt as a general, open question. Pretty sure that the answer is no.

      As a user only, I have years of experience with "on demand" or tankless hot water heaters. In a few ways, nice. On the other hand, they are fickle and variable regarding water pressure, volume, and temperature.

      First, the burner ignition "ON/OFF" trigger/switch seems to only turn ON at a certain amount of water demand (seems related to water pressure). Less demand and you'll get cold water running into and out of the heater all day long, no matter what kind of pump you use.

      Second, excessive pressure gives a better result, but still no hot water. Just warm.

      Third, it is tricky to keep the burner on. That also requires a certain and consistent amount of water demand. Too little demand and it shuts itself off, often requiring a short "OFF"/waiting period prior to re-activating. Especially "fun" during hot showers on cold days. Water demand can be harder to regulate during a shower than most normal system homeowners realize. That auto shut-off quirk would be exacerbated on a boat where, for water conservation, you might want to take Navy showers (water on, get wet, water off, soap, rinse). Also, some models turn the burner off after a certain amount of time, regardless of whether you're done using it or not. On those, I never found a time adjustment knob.

      So, would a manual pump work? Are those heaters good? Based on my experience, I don't see how, and yes, but only under nearly perfect conditions.

    2. My experience was on the island of Crete on a tiny Air Force Station. I was living in the"trailer". Think early air stream type trailers small enough to be pulled by a passenger car. circa 1950's. The trailers had been permanently mounted on cement foundations. They had standard (read variable pressure) water plumbed in. I can't recall there being a water tower so I don't know how pressure was derived. For all I know there might have been a large tank sitting on one of the over looking mountains (hills).

      The water heaters themselves were of european make and were OLD. There was a propane tank mounted on the tounge of the trailer and it was changed periodically by a local service. In other words I didn't have to mess with it. I don't recall it ever running out. All the propane suppled was the water heater and the kitchenstove.

      My memory is that I had as much hot water as I needed. I don't recall too much temp. variations. It took about a minute to get "hot". This was in 1976-78 so...memory you know?

      I know NOTHING about boats other than what I've read. would seem to me that an external mounting, on the deck? could be devised for the propane tank so that if/when some type of propane leak occured it would leak OUTSIDE the living quarters. Propane is heavier than air. I would also think that something similar could be devised for a water tank to supply pressure. Suppose a "pressure tank" were to be mounted at some easily reache distance up the mast (tenfeet?). Before you wanted to take a shower (or other wise need hot water) turn on a pump and fill the tank. Water would then be gravity fed to the hot water heater. Looooong showers would be impossible. (five gallons? ten?)

      I suspect a large (heavy) tank would be contra indicated that high above the deck. It could be drained while under sail.

      Just my two cents. I'd probably try something like that rather than have to manually move HOT water around inside the boat.

      hope this helps.

    3. Thanks Everitt. Moving hot water around inside the boat is what I was trying to avoid with my permanently mounted water pot/gantry idea. You sparked an idea though for a gravity fed solar shower though...haven't thought it through yet though...

  6. Continuing with my unrecognized contribution to the topic ;-), the following water heater is the smallest of this type that I've ever seen. Even it needs 20-80 psi of water pressure, though that is a mysteriously wide range for a minimum:

  7. Thanks Yoda...for both comments :-) I think I'm going to stick with the simple plan. I'm up against some local insistence on technological gewgaws though. I was told yesterday if I don't carry a life raft that explodes into a self contained emergency shelter complete with food, water, and a satellite beacon upon contact with water then I'm being fool hardy. Same goes for eschewing the electronics... putting our lives at risk. No pressurized water, power for the hair dryer and curling iron? How can I abuse my wife so? Well, she hasn't asked for any of it and I would accommodate anything she wants anyway. It is other people that are having trouble with the whole thing. There... I vented :-)

  8. Alan,

    I've been working on propulsion design recently for myself. Talk about anti-simplicity! I think I've come to more fully appreciate why Dave Zeiger has gone totally motor-less. ;-)

    Not that your wife's complaining, but a funny related note. I had the experience of taking a city woman camping for the first time outside of a cultivated "campground". Prior to the trip, it was nearly unimaginable to her. How will I eat? How do I use the toilet? How can I take a bath? In the river??? You must be kidding -- no way! First day, not so good. By third day, old hat. Years later, she regularly brags about it to friends as being so fantastic. Moral of the story: You don't know until you know.

    You wrote a post back at the beginning of your blog titled "Why?" It was well reasoned and well written. Stay the course!


  9. Thanks Yoda. I've talked the talk for years. Once people see, they'll get it.

    1. "Thanks Yoda. I've talked the talk for years. Once people see, they'll get it."

      Maybe. But even if they don't, that's OK. In the end, you and your wife are the only ones who really need to get it.

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  11. Alan,

    I loved this hot water idea. I think it could be very handy on land as well.

    When we built our house, we had a hot-water-carrying system. I had a ten gallon tub upstairs which drained straight to a shower head below. We would put in so much cold water from a spigot and then carry a pot of boiling water up our steep, rickety stairs and pour it in. Effective, but very dangerous. Now we have solar plus the pipes in the cook stove that Yoda mentioned.

    In the same vein, I got an idea for galley water pressure from home biogas plants where folks just collected the gas in a big plastic bag in the shed out back and tied a rope around it, which they would pull when they wanted gas to flow. I'll bet you could take one of those flexible water tanks that are kind of like wine skins and sandwich it between two hinged pieces of plywood. Mount it under the galley sink and step on the upper plywood to force the water up a tube to the faucet. The fill neck would have to be plugged off, but you would have pressure water without a pump. At least pump and tank in one.

    Enjoying your blog immensely.


  12. Thanks David! I'll probably splurge and buy a foot operated gusher pump. Plus a few spare diaphragms to hang on screw beside it.

  13. I'm not familiar with this type of pump. Are you thinking of this or something else?

    The product description seems to indicate that it is both 12v _and_ manual powered (vs. two different models). Does that seem correct?

    I noticed that the pressure rating on that pump was 60 psi. Enough to make that small tankless water heater work.

    (I discovered later that 20 psi is the minimum and 80 psi is the maximum for that water heater)

    1. The ad is confusing Yoda. I'm familiar with a very similar manual version - no power at all. Looks identical - had one on our Lancer sailboat. I can remember what the brand was.

  14. Interesting idea! It looks quite unique and efficient - without all of those possibilities of a scalding accident. I hope it works out well for you. It seems like you have got it covered for a lot of different possibilities, which is excellent. Have fun with it and good luck! Thanks for sharing this btw.

    Carmelo @ PRO Hot Water Service