Which Watermaker To Choose

[daddle]

Originally Posted by Roy M

Is anyone using the Spectra Z-Brane? Does it need to be energized 24/7? What does this mean in additional amp-hours/day?

Yes. The Z-Brane is on all the time, unless the membranes are chemically preserved. I asked the factory the current draw. I don't recall the answer but it was quite low. Far less than 1 Amp as I recall. It was so small as not to be a concern for the typical cruiser.

[delmarrey]

Here's a thread on them>>> http://www.cruisersforum.com/forums/...ane-37231.html

Originally Posted by Tellie

The electrical specs for a Z-brane are,
Input 12-30 VDC
Output 35KV DC @ 100uA

Originally Posted by noelex 77

Thanks for the info. That translates to 0.035W (assuming 100% conversion. It wont be 100%, but I would hope the efficiency to be high

[Ozbullwinkle]

Originally Posted by colemj

After over 4 years of full time cruising, our next watermaker will be an AC powered larger capacity one. We will probably be replacing our perfectly good 6gal/hr DC one next year for the above.

This is only our experience and preference, but when full-time cruising, you use more power and water than you think. Or you wish you could. We have been cruising where obtaining shoreside water is cumbersome and difficult, although it is always possible with enough effort and going out of ones way.

It is certainly easy to economize and conserve both water and energy, but then you are camping and this becomes old.

Regularly washing salt off the boat, doing laundry often and at will, showering frequently with fresh water after swimming (or just because it is hot and feels good), etc becomes more important the longer we are cruising.

The only cruisers we have ever met who didn't want more watermaking capacity already had higher output watermakers (>20gal/hr) ................................................


Mark

Spot on Mark, having an abundence of water is something that really enhances the cruising experience and life aboard. How good is it to be able to give the boat a good fresh water washdown & have a shower at will without the need for the old water on, water off, soap up, water on & rinse method.

So, when choosing a watermaker do not just limit it to one that meets your daily frugal water needs, step it up a bit so the days of scrimping and almost dreading visitors coming on board & wanting to take a shower while you dread the loss of your precious water are over.

[Pelagic]

Originally Posted by colemj

After over 4 years of full time cruising, our next watermaker will be an AC powered larger capacity one. We will probably be replacing our perfectly good 6gal/hr DC one next year for the above.

This is only our experience and preference, but when full-time cruising, you use more power and water than you think. Or you wish you could. We have been cruising where obtaining shoreside water is cumbersome and difficult, although it is always possible with enough effort and going out of ones way.

It is certainly easy to economize and conserve both water and energy, but then you are camping and this becomes old.

Regularly washing salt off the boat, doing laundry often and at will, showering frequently with fresh water after swimming (or just because it is hot and feels good), etc becomes more important the longer we are cruising.

The only cruisers we have ever met who didn't want more watermaking capacity already had higher output watermakers (>20gal/hr).

Particularly since the equipment that allows this is available and costs no more, and often less, than smaller capacity DC powered units.

Here is a dirty little secret about DC powered units: they only produce their rated output and quality when the voltage at the unit is 13.8V. That means you will have a charging source going anyway when running these units, and that charging source will be running longer to bring the batteries up to charge due to the simultaneous battery drain from the watermaker.

Almost everyone we know with DC units plan their use during motoring or running a generator. We have 480W of solar and that is enough to run the watermaker or charge the batteries, but not both unless we limit the watermaker to just an hour or the batteries are mostly full anyway. And we have a full sunny day.

So, if getting a DC unit, definitely go with an energy recovery type - you will either get the same output with half the energy input, or double the output with the same input. Particularly if you plan to run it off solar, as that will leave more power to recharge the batteries and you will have a fighting chance of running without needing a generator or engine run.

In contrast to much of what Tellie's experiences are, most of the people we meet with watermaker problems have Spectra units. However, and I want to be very clear on this, we don't meet many people whose watermakers have any problems at all (despite what everyone says about the fragility of these things) and for all we know, the majority of people out here may have Spectra units, which would make the few with problems actually rare, percentage-wise. And the Spectra problems are always the same ones: feed pump bad and automation controls messed up - both either easily fixed (carry spare pump) or avoided (I'm not a fan of automation here).

If getting an AC unit, my preference is to size it so that it is possible to run it off our inverter if the genset fails. This is ~30gal/day, drawing ~120 DC amps. This allows us to run it while motoring or charging using the engines (180A from the alternators).

Another consideration is to size it to run off a portable generator like the Honda 2000 (BTW, these Hondas are available EVERYWHERE - I would not be concerned about being without one). The size is about the same ~30gal/day because of the limited output of these generators. Keep in mind that if you go this route, the generator will be dedicated to running the watermaker - you will not be able to charge batteries or do anything else at the same time as you make water.

Above all - before purchasing a watermaker, make sure you have maximized your ability to catch and process rainwater. There is nothing like a high-capacity, zero-energy source of water! If you cruise where it rains hard once/week and you have a good rainwater catchment system (one that doesn't require you to sit pans all around the deck), you will not need a watermaker. During a strong rain, our hardtop bimini collects over 100gal/hr and it isn't even optimized for rain collection (I estimate only ~1/3 of the rain is collected).

Again, these are only my thoughts and preferences and what works best for us. Every boat, cruising style and needs are different.

Mark

Great Post and Advice Mark… On all sizes of yachts I have seen many underestimate a comfortable capacity to make water and end up unnecessarily compromising on cleanliness after a salty passage.

I found with my 500gal/day the 40 gallons I made in 2 hours of Gen use was insufficient if we gave the boat a fresh water wipe down or during laundry day for 5 of us…so we ran longer strictly to make-up our water loss. (I like to keep my FW tank Full)

Tom’s comment: 'If you want the 12/24 V DC backup, use one of the more power efficient AC systems and run it from the inverter until your genset is fixed'. is intriguing, as my old 1990 HRO System states 2.0Kw Power consumption for a 1.6HP motor.

Does anyone know offhand what a modern power efficient 1.6HP AC motor 220V/50Hz would consume, so as to see if my invertors could handle it?

[neelie]

Originally Posted by Pelagic

Does anyone know offhand what a modern power efficient 1.6HP AC motor 220V/50Hz would consume, so as to see if my invertors could handle it?

Can't tell you first hand. But can point you in the direction of Echotec who advertise AC systems that can be run off 2 and 3kW gensets or Inverters.

ECHOTec. Marine Watermakers*- Small Generator or Inverter Powered* AC Watermakers*(Modular)

They may be able to advise. I notice their 55GPH unit requires 3Kw or 8 Amps at 240V. I'm guessing that it probably has some kind of soft start capability.

I suspect that the starting current may be your limitation.

Please report back with your findings - it will be of interest.

[Tellie]

Originally Posted by Therapy

But you can't unless you go where he is. Spectra has lots of rules on who and what he sells. If I want one in Hudson, he can't sell it to me.

And he still will help anybody, anywhere. I used the phone........for hours. He couldn't even sell me filters once we left.

I don't know why he does it but he does.

Because of people just like you and your wife.

[noelex 77]

Originally Posted by Pelagic

Does anyone know offhand what a modern power efficient 1.6HP AC motor 220V/50Hz would consume, so as to see if my invertors could handle it?

The problem with this approach is not just getting a large inverter, but generating the power necessary. For a medium sized yacht often the alternator cannot keep up with the demand, especially at idle revs. This means running the main engine to make water, then to replace the power deficit, then to charge the batteries.
The engine run times can become very long and impractical.

This is not universal, a couple of large (especially 24v) alternators on the main engine can make this a viable backup, but for a great many boats who rely on an AC watermaker,a breakdown of the generator,means putting into port and waiting for repairs.

[colemj]

Originally Posted by noelex 77

but for a great many boats who rely on an AC watermaker,a breakdown of the generator,means putting into port and waiting for repairs.

Or buying a Honda genset, or only running the watermaker while the engine(s) are running (100A alternator will be fine) and letting the solar/wind recharge the batteries as they normally do.

I don't think this situation is as dire as pulling into port and waiting. Most people considering an AC watermaker come to this decision because they are running their motors or generator anyway to make water, even while having alternative charging sources. It takes a lot of power to keep batteries charged AND run a watermaker a couple hours/day to keep up with usage.

If one is reliant on the generator so they cannot make water any other way, then they are relying on the genset also for primary charging and other high-current usage. In this case, they will be in port for repairs if their genset breaks regardless of the water situation.

20-40gal/hr is a lot of water, and taking an hour out of battery charging time while motoring to make the day's (and the next day's, and possibly the next) water is not so onerous.

Mark

[Pelagic]

Originally Posted by colemj

...If getting an AC unit, my preference is to size it so that it is possible to run it off our inverter if the genset fails. This is ~30gal/day, drawing ~120 DC amps. This allows us to run it while motoring or charging using the engines (180A from the alternators).
Mark

Thanks Neelie saw your earlier post and started researching ECHOtec.

My goal is the same as Mark …to size a larger capacity R/O System that could run off of my 3000 Watt Victron Invertor. (Primarily underway when I don’t need or like to use my 10KW AC Gen)

Problem is that on startup I believe you would be pulling more load than the Invertor can deliver. ECHOtec does offer optional soft start, but that starts to get complicated.

Then I got to thinking, the Invertor is really to utilize my large 24 Volt DC system, as batteries can be charged by my main engine alternators, generators and 24V shaft generator while underway.

So I looked at their DC Water makers for yacht (not recovery-system) like their
780-DML ECHOTec. Marine Watermakers*- DC Watermakers for Yachts*12 or 24 Volt*(Modular)

For my setup with lots of 24volt charging capacity via 2 Victron Chargers (Total 120 amps) I would not be limited to the capacity of Invertor.

Not an electrician, so am I missing something?
Is a DC motor driving same pump, inherently less efficient?

[carstenb]

I guess I'm still flabbergasted at the amounts of water that many of you apparently use. Honestly, I don't even use that much on the hard in my house.

I'm with Seaworthy lass. When we sail, I usually just dry off the boat in the morning when there is lots of dew. I carry a Chammy (?) and it only takes a couple of minutes.

I have a solar shower. We jump in the big pond and rinse off with that. Even when we go into marinas every night and here in Denmark, water is free, good and available at every dock, we still only use 30, 40 liters (liters - not gallons) per day.

[goboatingnow]

Originally Posted by carstenb

I guess I'm still flabbergasted at the amounts of water that many of you apparently use. Honestly, I don't even use that much on the hard in my house.

I'm with Seaworthy lass. When we sail, I usually just dry off the boat in the morning when there is lots of dew. I carry a Chammy (?) and it only takes a couple of minutes.

I have a solar shower. We jump in the big pond and rinse off with that. Even when we go into marinas every night and here in Denmark, water is free, good and available at every dock, we still only use 30, 40 liters (liters - not gallons) per day.

Me too, 4 lads crossed the Atlantic on approx 4-5 litres a day per person inc cooking. We arrived with half a tank of water . Mind you we hadn't washed in 4 weeks and the clothes were a little wiffy..........


Dave

[Tellie]

Originally Posted by carstenb

I guess I'm still flabbergasted at the amounts of water that many of you apparently use. Honestly, I don't even use that much on the hard in my house.

I'm with Seaworthy lass. When we sail, I usually just dry off the boat in the morning when there is lots of dew. I carry a Chammy (?) and it only takes a couple of minutes.

I have a solar shower. We jump in the big pond and rinse off with that. Even when we go into marinas every night and here in Denmark, water is free, good and available at every dock, we still only use 30, 40 liters (liters - not gallons) per day.

We Americans haven't quite caught up to the water conservation many other countries use. I believe the average household here uses about 400 gallons per day. Also, many owners of boats are quite particular on how their boats are washed down. Many use dock side water softening systems. Also when it comes to sizing a watermaker I try to throw in a few wash downs as well into the total output capacity. RO water is far better and more gentle on surfaces than dock water and leaves practically no residues after drying. As stated earleir, watermakers are not just for drinking water.

[colemj]

Like I said, it all depends on your cruising grounds and style. We haven't reached a dewpoint in 4 years. Sitting behind reefs with waves exploding over them during tradewind season in parts of the Caribbean puts a thick covering of salt over your boat every day. High heat and humidity makes you want a fresh water shower after swimming - and you swim a lot to keep cool. And we probably drink 1-2 gallons of water per day each.

I don't think we would even need a watermaker if we were cruising Denmark, where it is relatively cool and rains regularly (and the beer is better for drinking).

Mark

[Pelagic]

Originally Posted by carstenb

I have a solar shower. We jump in the big pond and rinse off with that. Even when we go into marinas every night and here in Denmark, water is free, good and available at every dock, we still only use 30, 40 liters (liters - not gallons) per day.

Hi Carstenb, having lived on yachts most of my life I agree with Mark:
The only cruisers we have ever met who didn't want more watermaking capacity already had higher output watermakers (>20gal/hr).
That is for a boat with 2 while I am sizing for 5 or more on board, making water only 2-3 hrs. a day

Cruising in the Tropics, shore water is not that safe and the heat and humidity tends to increase the freshwater use. Also marinas are few and far between in Asia.

Having bare-boated out of Kolding, I am impressed that you jump into the pond. Brrrr.!~

[Bash]

Originally Posted by Tellie

We Americans haven't quite caught up to the water conservation many other countries use. I believe the average household here uses about 400 gallons per day. Also, many owners of boats are quite particular on how their boats are washed down. Many use dock side water softening systems. Also when it comes to sizing a watermaker I try to throw in a few wash downs as well into the total output capacity. RO water is far better and more gentle on surfaces than dock water and leaves practically no residues after drying. As stated earleir, watermakers are not just for drinking water.

Indeed, some of us are so decadent we plumb the heads to flush with freshwater.