Very small water-maker oder Big one for very fast refilling?

[daletournier]

I have a rainman 30 gallon per hour. My last boat had a 12v katadyn 80e. I much prefer the big ac driven watermaker.

I also have 2 power sources, generator or inverter, inverter is purely a back up.

I like the big ac driven watermakers like Rainman or the cruise RO because they are very simple and just work. I run it once every 5 days and make a heap of water.

I'm certainly not opposed to the likes of spectra BUT your suggestion of a small 12v running all day IMHO is unrealistic. The Katadyn is quite noisy.

[Mike OReilly]

People have mentioned the noise of these 12v water makers a few times. I dislike noise on my boat, so this does matter to me. I know “noise” can be a subjective concept, but how much noise are we talking?

Don’t suppose anyone has a video with audio showing how noisy various WMs are? I’ve actually seen a few of the powersurvivor 40e in action on youtube. They don’t seem that loud, but it’s hard to know out of context.

[a64pilot]

Whether it’s 12v or 120v is irrelevant to the watermaker, just as if the power comes from an inverter or a generator.
They are excepting for the Spectra and I’d assume one or two others essentially power washers, and that piston pump at high RPM is noisy.

DC watermaker only makes sense to me if it’s highly efficient, if your going the pressure washer pump route, go for high volume so you minimize the noise and engine run time.

Or spend the bucks for a Spectra if your going DC.

[Capt.Don]

Originally Posted by Mike OReilly

....I’d love a Spectra 150. Highly efficiency. Problem is, I can’t fit it (not without major surgery).....:.

Mike,
I was able to creatively fit the Spectra 200 in our 35' Tartan. Pump and filter creatively fit under the sink and the Clark pump in one of the settees. We also considered the Katadyn 40E, put finally decided to spend extra $$$ for the Spectra. The 40E is noisier and will run need longer run times. We run a couple of hours ever 2 or 3 days off solar/batteries -or- when motor sailing. Never an issue with power - just run when needed.
Don

[Mike OReilly]

Originally Posted by a64pilot

Whether it’s 12v or 120v is irrelevant to the watermaker, just as if the power comes from an inverter or a generator.
They are excepting for the Spectra and I’d assume one or two others essentially power washers, and that piston pump at high RPM is noisy.

The vids I’ve seen of the powersurvivor do not appear to be running at high RPMs. If anything, it looks rather low to me. Is this not the way they operate?

https://www.youtube.com/watch?v=uDfJTHW9-H0

Originally Posted by Capt.Don

Mike,
I was able to creatively fit the Spectra 200 in our 35' Tartan. Pump and filter creatively fit under the sink and the Clark pump in one of the settees. We also considered the Katadyn 40E, put finally decided to spend extra $$$ for the Spectra. The 40E is noisier and will run need longer run times. We run a couple of hours ever 2 or 3 days off solar/batteries -or- when motor sailing. Never an issue with power - just run when needed.
Don

Thanks Don. I’m sure I could find a way to fit a Spectra, but not without a fair bit of effort. I’d certainly be willing to do this if I really needed one, but as I’ve said, this is currently in the “want” category, not “need.” And quite franky, I simply can’t justify the high cost of either right now.

We already carry 200 gallons of water, and are pretty modest in our usage (1 gallon/person, so 2 gallons/day). I would have to run the powersurvivor for a few hours every few days to keep up with our demand, which doesn’t seem like a big deal. If I had a spectra I’d have to run in maybe once a week for a few hours, or perhaps every three or four days for an hour or so.

Efficiency is important to me, but in my case both the Spectra and the powersurvivor, or any other WM, would be running off excess solar, so it doesn’t really matter that the powersurvivor runs at higher amps/gallon.

[sailorboy1]

I feel the choice is simple:

- if you have a generator (Honda type or installed unit) get an AC watermaker and get the job done and out of the way
- if you don't but have lots of solar get the DC and just put up with it running most of the time

and if you REALLY want to get it done fast, install an engine driven unit

[john61ct]

Originally Posted by a64pilot

Whether it’s 12v or 120v is irrelevant to the watermaker, just as if the power comes from an inverter or a generator.

Exactly. The critical distinction is

high gph throughput, short runtimes, requires high wattages, less energy efficient

as opposed to

energy efficient, lower gph, longer runtimes

Either DC or AC motors can service either type.

Rich @CruiseRO will happily substitute a DC motor in his high-gph systems, allowing big alternators or a DC genset to supply the power.

Or even solar if you have kWs of panels and a big LFP bank, 2-3 hours twice a week would be my target.

I personally have no interest in **any** machinery that runs often and for many hours at a time, even if it's just a quiet background humming.

[john61ct]

Originally Posted by sailorboy1

if you REALLY want to get it done fast, install an engine driven unit

Or from high DC output from large alternator(s) or dedicated DC gennie.

Same source can charge eutectic holding plates as well, but of course for that usage needs to run more frequently than a watermaker.

[jmh2002]

Cost needs to be thrown into that mix too though, since that is a consideration for many cruisers.

And not just the cost of the unit, but also whatever is involved in powering and running it.

In Mike's case the Spectra is ultimately 'better' for him, but at what cost?

Cheaper and simpler might actually be better for cruisers similar to Mike.

[Dockhead]

I've never known anyone with a watermaker, who wished he had a smaller one he could run for longer periods at a time. YMMV, but they are noisy and have to be kept an eye on, and most people will prefer to make their water over a few hours at a time when the boat is in good clean water and the engine or genset is running.


You can buy efficient DC ones with Clark pumps, but I don't see the point of this complexity. If you've got a diesel engine running anyway, then you don't care so much about the efficiency -- you just want to get it over with.



Thus my choice would be a big and extremely simple one.


The OP should make sure he really needs a watermaker, however. I don't know any place within 1000 miles of German waters where a watermaker makes any sense whatsover. Watermakers are useful for crossing oceans or spending weeks at a time away from easy access to water from shore, something not required for cruising in any European waters other than perhaps the dry Eastern end of the Med. Otherwise, good tankage is a better, simpler, and far cheaper solution.

[Dockhead]

Originally Posted by john61ct

Or from high DC output from large alternator(s) or dedicated DC gennie.

Same source can charge eutectic holding plates as well, but of course for that usage needs to run more frequently than a watermaker.

What difference does DC vs AC make? None at all if you have a decent inverter/charger.


The large capacity cheap and simple watermakers are almost all AC powered, just like 99% of gensets, and that is just fine.

[Dockhead]

Originally Posted by sailorboy1

I feel the choice is simple:

- if you have a generator (Honda type or installed unit) get an AC watermaker and get the job done and out of the way
- if you don't but have lots of solar get the DC and just put up with it running most of the time

and if you REALLY want to get it done fast, install an engine driven unit

I think that's generally correct, but I would not personally ever have an engine driven high pressure seawater pump on a boat of mine. All it takes is one pinhole in one high pressure hose to destroy everything in your engine room, which might even cripple the vessel in the middle of a long passage.



My boat was designed with a dedicated separate waterproof compartment for the watermaker and dedicated day tank to receive the watermaker output and ensure quality before it's transferred to the main tanks. That's best practice, but if you can't arrange that, at least put the watermaker somewhere where a seawater leak won't cripple essential systems. Watermakers pump seawater at huge pressures which can make incredibly destructive leaks.


A fourth option no one has mentioned so far is a portable watermaker like the Rain Man. This has some really profound advantages -- no installation, no risk to boat systems, perfect access to components for servicing, easy to get rid of or take off and store if you stop crossing oceans, etc etc etc. A really nice, albeit expensive, solution for many boats.

[noelex 77]

Originally Posted by john61ct

Exactly. The critical distinction is

high gph throughput, short runtimes, requires high wattages, less energy efficient

as opposed to

energy efficient, lower gph, longer runtimes

This is not really correct. The distinction is whether or not the watermaker has an energy recovery design. If it does have energy recovery (Spectra is the most common brand), the power consumption will be much lower.

Both energy recovery and non energy recovery watermakers are available in models that produce high gph outputs and models that produce small gph outputs.

If a non energy recovery watermaker is chosen, it is not generally practical to operate the watermaker via solar or solar/wind. A generator, or at least the main engine with a large alternator, needs to be operating when the watermaker is running. Therefore the best strategy is to fit a very large watermaker so the run time is short.

If an energy recovery watermaker is fitted, this will normally be powered by solar/wind and therefore a short run time is not needed and a lower capacity watermaker will work well.

When choosing a watermaker, the first thing to decide is how you are going to produce the power the watermaker will need. This, more than anything else, will dictate the type of watermaker that will suit you best.

[noelex 77]

Originally Posted by Dockhead

You can buy efficient DC ones with Clark pumps, but I don't see the point of this complexity. If you've got a diesel engine running anyway, then you don't care so much about the efficiency -- you just want to get it over with.

Yes, but if want to run the watermaker via solar/wind/hydro you need to select one of the energy efficient models.

[Matt Johnson]

The energy recovery based watermakers (in the size you are looking) are powered off a pump just like your typical Shurflo/jabsco pressure water system on most boats. It sounds like when you leave a water tap open and the pressure water pump is running to keep up. The Katadyn is more of a wooshing sound with a strong mechiancial background noise of the piston working back and forth. Mounting location and the mounts used dictate the sound level for either of these units.

One of the best locations for sound and space is to mount the Katadyn to the underside of the deck suspended by soft mounts. It's out of the way in typically unused space, no vibrations through the boat, and often easy to get to. The only negative is water lift height and if you were to have a leak (not unheard of with the Katadyn).


Matt

P.S. the Katadyns are very easy to break down and rebuild, but the membrane is proprietary and stupid expensive.

Originally Posted by Mike OReilly

People have mentioned the noise of these 12v water makers a few times. I dislike noise on my boat, so this does matter to me. I know “noise” can be a subjective concept, but how much noise are we talking?

Don’t suppose anyone has a video with audio showing how noisy various WMs are? I’ve actually seen a few of the powersurvivor 40e in action on youtube. They don’t seem that loud, but it’s hard to know out of context.