Size of water maker needed/recommended for 2 living cruising full time.

[Cheechako]

I think the power source as mentioned is the key. 60l/hr should be fine. But if you are gong to run a gen set anyway then why not the bigger.
I found often (engine drive) I would just make water the last 2-3 hours underway if the engine was running and didn't have to make water for a week or so at anchor.

[wrwakefield]

Originally Posted by BOKKIE

We are purchasing a Helia 44 Catamaran with 3 cabins / showers and clothes washer. The manufacturer has 60L or 180L / hour water makers. I have heard that if you don't use them enough they can run foul. I also don't want to skimp water. I also don't want to draw unnecessary power. I lived aboard a long time ago and hated running back/forth carrying water, and being extremely frugal. I will have a fresh water hose for the deck and outside shower. I would love to hear peoples opinions. Is "bigger better" or smaller more efficient and less chance of going "foul"? Thanks.
Cheers.

Welcome to the forum, Bokkie.

We are a full time couple with a clothes washer, 2 showers, selectable fresh and salt water wash down on deck and in the anchor locker, etc.

Our [older model] Spectra produces 12 gallons/hr at just over 1 nominal 12VDC amp-hour per gallon. According to the manufacturer's documentation, it prefers longer run cycles, and to be fresh water flushed every 5 days.

With our 220 gallon potable tank capacity, running the water maker every ~5 days for a few hours is our normal cycle. [We always try to run it while one of the two 110 gallon potable tanks is still full as a hedge against Murphy...]

We take no special water conserving measures other than to use what we need, and need what we use...

If you are interested in perusing more details about water consumption I have a blog post with additional information including metrics on land and sea.

If I changed to an AC powered water maker in the future [no plans at the moment...] that was generator dependent, then I would want a greater gph capacity to minimize generator run time.

Best wishes with your project.

Cheers!

Bill

[Maka]

Great Conversation.

[sailorboy1]

I'm reading with interest. I was thinking a 20 gph AC powered unit. That would seem to be able to handle two people in plenty of hot water. But people say that 30 gph would be better for a couple tell me now as it is less expensive to do the first time than to change it later.

[a64pilot]

I go with the idea if it's going to take a generator to run it, get a big one so generator run time is short.
The Cruise RO 30 GPH one will run off a Honda 2000 with enough juice left over to charge batteries too.

But if I were to go with a DC one, a Spectra would be my choice, due to I think nothing makes water for less energy per unit of water, Liter or gallon


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[BOKKIE]

Thank you to everyone for input, advice and great responses. I am new here, but love this forum. Everyone is really helpful, kind and not patronizing to Newbies. Everyone seems eager to share there experience and knowledge.
Thanks for making me feel welcome.

[SV THIRD DAY]

Originally Posted by sailorboy1

I'm reading with interest. I was thinking a 20 gph AC powered unit. That would seem to be able to handle two people in plenty of hot water. But people say that 30 gph would be better for a couple tell me now as it is less expensive to do the first time than to change it later.

The price difference between a 20GPH water maker and a 33GPH water maker is $855, with the ONLY difference being one or two 40" membranes. So the advantages in that $855 are:
1. 50% more water in the same generator run time for either less generator run time OR having more water for fresh water deck and anchor chain rinse downs
2. Built in redundancy, because if one of the two membranes was to fail, you can easily replumb the membranes to run on a single membrane until you get a replacement and make 20GPH rather than zero.

But the good news is that you can upgrade from a 20GPH to a 33GPH at any time down the road for that same $855 price differential. So if the $855 is important to your budget, you are not forever stuck with it when you find out a cruising truth which is more is better with water and power on a cruising boat....smile.... The 33GPH is our best selling water maker by a 4:1 margin, by the way.

Here is the manual to download:
www.cruiserowaterandpower.com/uploads/sm30.pdf

Back to work now on the boat....all news hoses and beat exchangers....it never ends.

[Tri]

We are 3 on board and our main water consumption is to shower (especially after swims multiple times a day) and to do dishes.

We have a 60L/h 12V AquaBase that is run off the solars. We have a 120 L water-tank and use the water maker whenever needed, typically every other day or so. The advantage for us on 12V is that it can be run off the battery and solars (without the need for an inverter). This 12 V type is also a very silent water maker (low pressure) that you hardly hear in its sound proof box. So running it is not a big disturbance.

I had Onan generators on previous boats but would not want to go back to that because it feels like living on a construction site. Same with running the engine to make or heat water. So a 12 V water maker was our natural choice and 60 L / h is pretty much the limit here. Like said for us 3 that is enough.

Voluntary simplicity :-)

[carstenb]

This subject is always interesting because generally americans use one heck of a lot more water than europeans.

We have a 30 ltr/hr spectra (uses 8 amps) and 2 x 140 liter water tanks. A tank of water typically last us 3 days, so we run the water maker every 2 to 3 rd day for 3-4 hours (again typically when the batteries are fully charged and the solar is wasted anyway.

The size of four watermaker is really dependent on 2 things - your usage (check this before you buy) and how much power do you have available

But as a general rule - get as much capacity as you can - you'll rarely wish you had less water

[Tri]

You also have to consider how long you can actually run the desal. If you are at an anchorage with a lot of other boats you may not want to use the desal during everybody's bathroom hours. So it is a quick run outside these hours (being happy to have opted for the bigger model) or a pleasant sail outside "contamination" to fill the water tanks.

[sailcrazy]

Another consideration T thought about, after I made my last post, is parts availability. We have not had any mx issues yet, but Murphy is alive and well...stuff wears out and breaks. Whatever brand you elect to buy, consider parts availability and repairability. Having to go back to only the manufacturer for bits and parts can be an issue, depending on where you cruise. Some watermakers are made up of commonly available parts, and others are proprietary.....just something to think about.

[a64pilot]

One reason I think Americans do use more water is we tend to cruise warm waters more often (Caribbean) and swim a lot, if it's hot a nice way to cool off is a swim, and who doesn't want to rinse off with fresh water after the swim?

I know an RO unit will filter bacteria, but it may also filter so fine that it excludes viruses?

[GordMay]

Originally Posted by a64pilot

... I know an RO unit will filter bacteria, but it may also filter so fine that it excludes viruses?

Indeed.
A desalinating R/O watermaker membrane will not pass a dissolved salt molecule, which is smaller (at 0.001 micron) than most bacteria & virus’ (at ±0.01 micron) - hence it will also filtre those larger pathogens.

Note: This should not be understood to mean that you should treat bacteria/virus-contaminated water with an RO unit. That isn't its purpose, and the O-ring seals in reverse osmosis units are not designed to prevent the migration of bacteria.

In a paper titled “Removal of biological and non-biological viral surrogates by spiral-wound reverse osmosis membrane elements with intact and compromised integrity”, the authors found a correlation between rejection of viruses and rejection of sodium chloride, where an increase in salt passage would indicate an increased passage of viruses across the membrane.
See ➥ http://people.ce.gatech.edu/~jkim/do...gh%20RO%5D.pdf

[SV THIRD DAY]

Originally Posted by carstenb

This subject is always interesting because generally americans use one heck of a lot more water than Europeans.

Anyone that has ever stayed in a house in Europe and seen those little tiny hot water heaters up on the wall...would certainly agree with this!

[a64pilot]

Originally Posted by SV THIRD DAY

Anyone that has ever stayed in a house in Europe and seen those little tiny hot water heaters up on the wall...would certainly agree with this!

I lived in one, and I thought that box pure genius. Mine heated the house as well as heated the water for a bath or shower. True it did not give a high flow of hot water, but an endless supply of hot water so you would never run out. But what impressed me was that little box also heated the house, I thought the dual use smart.
Being in Germany, and Germans being the way they are, it was inspected pretty frequently to ensure it wasn't polluting, which I also thought pretty cool.
Water was expensive though, and none of the Germans would drink the water that came out of the facet or at least none of my neighbors. They went to great lengths to conserve water, capturing the water from the roof for their gardens etc.


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