Source of hot water while cruising

[boatpoker]

Originally Posted by jpendoley

I have a unit by a company called Precision Temp, believe it meets all applicable safety standards, big issue is having a sealed combustion chamber and direct overboard venting. All propane devices should be home runned from the tank-no t’s.

I love it. I only carry liability insurance as my boat is quite old, but am very comfortable with the unit.

I'd never heard of this unit before so I looked it up. The instructions say that combustion air must be drawn from outside and exhaust air must be exhausted out the the "RV" but don't show any relevant fittings or provide instructions. How do you accomplish that ? This is one of the reasons the other brands do not meet ABYC requirements.

[Bentwings]

That’s what I had in mind.
In a live aboard since the raw water, in my case the river does not freeze so it possible to use the gen year around. A diesel would be better in othat they are more fuel efficient but when it is -20 F and the shore power goes out you will have more than enough heat. It’s not the cheapest heat but cost is not the issue when it’s a blizzard up here.

[john61ct]

Yes a portable camping setup to run outside is certainly a low-cost KISS solution and likely safer, as long as the "downhill flow" of any leaking lpg is not down into the hull.

Similar to running a suitcase inverter genny, for when living on the hook long term without using the big ICE.

Getting the heated water down and in to where it's needed in sufficient quantities is the greater challenge. I suppose if plumbing is used for that rather than a bucket, it might be possible to rig some space heating off it as well, ideally integrated with the ICE-heated hydronics.

Pretty limited audience with such a use case though, small boat minimum funds off grid liveaboard in freezing weather, wow not me thanks.

[Bentwings]

The big issue is just getting water to the boat in the first place. The dock water is turned off at some point. Keeping the main tank from freezing is another. It’s not really accessible so just blowing heat towards it probably won’t work. I’m going to look into other means. I can drag water down from the station wagon ( yeah, I really do have a big one) but it is a chore. Buying water just seems outlandishly expensive. Factors to weight here. I make my daily coffee and wash dishes. The head and clothes washing and bathing can be done up at the club house. Still that is a huge inconvience when it is -20 deg. and winter stormy. Again it’s something I have to consider for next year.

If I install the washer/dryer I’ll definitely need a water supply. There is a marina just a couple blocks away that has year around water but they didn’t have any available slips. There are a number of live aboards on the current pier. 4 on my side alone. My slip is only temporary. I’ll get a new location in the spring.

[boatpoker]

Originally Posted by Bentwings

The big issue is just getting water to the boat in the first place. The dock water is turned off at some point.

The liveaboards here run a spider web of hoses under water with the ends tied up under water (one at each boat). Want to fill the tanks. Pull up the end at the boat, pull up the end on shore and connect at laundry room ..... we fill 20 boats this way.

[mtns2marinas]

Originally Posted by Privilege

I have an instantaneous propane water heater. Search for one that doesn't need 110v for ignition. A single 'D' cell battery will last years. Two barbecue-size tanks last me four months - full time live aboard. The extra safety concerns are not an issue as i already have a propane stove plumbed in. The only downside is that it needs to vent overboard which I have achieved with a mushroom vent.

Which model propane heater did you install and where did you vent the mushroom vent?

[LoudMusic]

Originally Posted by Kenomac

We run the generator to energize the heating element inside the hot water tank.

My port engine's cooling loop heats the water tank, but the generator does not. This seems like a major flaw, considering that "generating electricity to heat water" is one of the reasons to run the generator. Even if I had to flip a bunch of valves so that only one engine's cooling loop went through the heater it still seems like a useful configuration.

[Leo Ticheli]

We've used the cheap black bag sun showers and they work well, but I prefer the little two gallon hand-pumped pressure bottle shower. It has a black cover, but doesn't get hot enough in the sun to suit me, so I either use the boat water that's been heated by the engine, or I boil a kettle and add that water to cold; it takes very little to heat the whole container, and the pressurized spray is much superior to the gravity pressure of the black bags. I like the nozzle control a lot better as well, and actually prefer the hand-held sprayer to using the built-in shower in the head which has no off-function on the sprayer.

"What shall we do with a dirty sailor? Put him the bilge and wet him all over."

Fair winds,
Leo

[CaptTom]

Originally Posted by LoudMusic

My port engine's cooling loop heats the water tank, but the generator does not. This seems like a major flaw, considering that "generating electricity to heat water" is one of the reasons to run the generator.

I consider it a great way to load up the generator while I'm charging the house bank or cooking on the electric range. I'm not sure how long it would take to heat the tank using genset jacket water, but that may also be an issue.

The house bank, and the hot water, seem to both take about the same time to top off. In other words, if I've been on the hook for 18-24 hours, I might have to run the genset for an hour before the tank is fully hot and the battery charger is in float mode. If it's only been 6-12 hours, it may only take a half-hour.

Still, it wouldn't be hard to wire up a solenoid valve to open the jacket water loop from the genset when it's running. Then "T" that into the existing jacket water loop from the main. I installed a valve like that to prevent a gravity flow from developing between my water heater and the main. Otherwise the heat exchange works in revers and the water heater just warms up the main.

[Bentwings]

Capt Tom, that’s exactly what I’m interested in. It will be a winter time project this year. Since I work part time in a fab shop and do all the TIG welding coming up with a custom fitted tank won’t be a proble. My boar has a surprisingly large amount of room right at the transom.

I’m going to get a small electric pressure washer this week and scrub the engine room.....it’s a grime pit now.

The water hose in the river is exactly what the marina down the street uses. I’m going to talk nice to the owner here and see if he might do this too. They are nice people and the live aboards do pay extra plus there are a couple “ bar flys in the group that keep the saloon alive in the winter. Sadly LOL.

[Quadrille in JB]

I’m surprised that no one has responded to sguerro1971’s comment on 12v water heating elements that can replace 110vac heating elements.
Checking out Missouri Wind and Solar’s site shows that you can heat 1 gal of water 1 degree using ~2.5 watts in 1 hour. So...2.5w x 10 gals x 10 deg gets you 10 gals of 10 deg hotter water for ~250w or ~21amps at 12v. Or bring 10 gals up 20 deg in 2 hrs. This is very possible for me with our 800+ah agm bank and our 720 w PV panels.
This sounds pretty good to me. Am I missing something?

[LoudMusic]

Originally Posted by CaptTom

I consider it a great way to load up the generator while I'm charging the house bank or cooking on the electric range. I'm not sure how long it would take to heat the tank using genset jacket water, but that may also be an issue.

The house bank, and the hot water, seem to both take about the same time to top off. In other words, if I've been on the hook for 18-24 hours, I might have to run the genset for an hour before the tank is fully hot and the battery charger is in float mode. If it's only been 6-12 hours, it may only take a half-hour.

Still, it wouldn't be hard to wire up a solenoid valve to open the jacket water loop from the genset when it's running. Then "T" that into the existing jacket water loop from the main. I installed a valve like that to prevent a gravity flow from developing between my water heater and the main. Otherwise the heat exchange works in revers and the water heater just warms up the main.

That's a good point. Most recently I just fired up the air conditioners to put load on the genset while charging.

I like the idea of having a solenoid activated valve, though. More things to think about ... and spend money on. My wife is going to hate me!

[Dockhead]

Originally Posted by LoudMusic

My port engine's cooling loop heats the water tank, but the generator does not. This seems like a major flaw, considering that "generating electricity to heat water" is one of the reasons to run the generator. Even if I had to flip a bunch of valves so that only one engine's cooling loop went through the heater it still seems like a useful configuration.

There are calorifiers with THREE loops -- engine, central heating, and generator.



Or you can simply use plate type heat exchangers, which are now less than $100 in a lot of places.


Once you are harvesting waste heat with heat exchangers, you can also space heat with it. I really wished my boat was set up this summer, sailing in the Arctic. But although the engineering is straightforward, it's still a whole project, and you have to ask yourself -- it is worth a weekned of work and a grand or so of hoses, heat exchangers, circ pumps, etc., just to run my generator (or central heat) a little less? I designed such a system for my boat a few years ago, and then abandoned it for that very reason.


But this summer, I was regretting that decision.

[wingssail]

Originally Posted by john61ct

Sorry did I miss specifics?

Those using propane instant HWS please post the make / model you recommend, and ideally links.

I may want to use on land anyway.

Never mind cost issues.

32 years ago we decided to get a propane water heater. The idea was to be as comfortable at anchor or at sea as we were at the dock (less reasons to justify staying at the dock). We bought a Paloma. Now, after 32 years, we are on our fourth one. It lives in the head, near the galley and near the shower, and it tee's into the boat's propane system, controlled by a Marinetics Solinoid.

It works perfectly. It is nice to sail into an anchorage on a cold and wet day, drop the hook, and have a hot shower. Also to start with hot water when you make coffee in the morning.

This one is a Cinsa, https://www.famsa.com/calentador-de-...0a&fo_s=gplamx
. It is the best and works on low or high water flow, although the solenoids are noisy.

They are common in Asia, called Califonts in Oceania.

[wingssail]

Originally Posted by mtns2marinas

Which model propane heater did you install and where did you vent the mushroom vent?

We use a Cinsa (https://www.famsa.com/calentador-de-...0a&fo_s=gplamx) it's the fourth one we've had in 32 years.

We vent it through a hatch in the head where it is mounted, about 24 inches away. and it is about 10 inches from the overhead.