I can't believe that this thread is still going!!!
1) As I wrote weeks ago, I own and love my Spectra Ventura MPC-5000 (working great for > 6 years and >12,000 miles offshore), and I have also stated my appreciation for Rich's (Cruise RO) larger units...
I think either of these are fine choices, depending on your specific application and your on-board energy generation/storage....
And, I also pointed out quite bluntly what some have been dancing around....that "watermaker decisions" are very subjective, and should be based on YOUR needs/desires, and most importantly on what your on-board energy generation and
storage capabilities are!!!
I think most of the above is accepted my most of those here....
And, together with Tellie, Pelagic, Nolex, Colemj, etc. we have discussed this in detail....so, I'm sure what else there is for me to say....
2) And, while I thank Mark (colemj) for relating his experiences, and agree with a lot of what he wrote, I do have a couple questions/clarifications....
Quote:
Originally Posted by colemj
You will still need a running charging source to meet output specs because these units are spec'd at 13.8V.
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I cannot speak for other brands, but Spectra publishes their product output specs at the nominal battery voltage of 12vdc(or 24vdc) not 13.8vdc....
My Spectra Ventura's specs for its "rated output" are actually shown at 12vdc (and 77*F seawater temps), at 6.3gal/hour (150gal/day)....
Spectra Watermakers - Marine Watermakers - Ventura 150
And, for more than 6 years, I have found significantly higher product output of 6.9 gal/hr - 7.4 gal/hr (depending on battery voltage and seawater temp), and I generally figure on an average of 7gal/hr at about 8 - 8.5 amps of
current draw....)
Watermaker
4706109
3) Regarding the relative pricing of the various units.....I'm a bit confused, as I see little difference in the actual prices, although there are large differences in the "price per gal/hr".....
Quote:
Originally Posted by colemj
.... I agree that if one has sufficient solar/wind, one can run a lower output DC system for long periods of time. However, this isn't really practical unless one has an energy recovery system. These are VERY expensive and another debate altogether. It really is about amps per gallon, but the price wall makes the decision complicated.
If money is no object and one has enough wind/solar to provide daily energy PLUS water (and you know this is true from actual experience with your usage and systems and not a paper calculation), then I agree that a Spectra/Schenker makes sense.
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I find the Spectra Ventura 150 selling for about $5000 (a bit less if you get a "boat show discount"...and Rich's
Cruise RO units selling for about $4200 (20 gal/hr) and $5000 (30 gal/hr)....
Ventura 150 and 200 Series Watermakers
20 GPH Water Maker
30 GPH Water Maker
So, I am confused by the statements that these "energy recovery" units are VERY expensive.....
Yes, the bigger units are more expensive....the
Newport 400 is about $7700 and the bigger 700 is > $10k.....
But, the point is that with these high-efficiency / "energy recovery" units, you CAN use a lower-capacity unit (approx. 7-8 gal/hr) and they CAN be run for longer periods of time, using solar-charged battery power, etc. and the "larger capacity units" are not needed....
So, if you compare watermakers by what they'll actually produce for you, on your boat, using your energy systems, over the day/week/etc. and the energy they use over the course of the day/week/etc. to produce that water, then in MY opinion, you may see that the Spectra's are not that pricey after all...or not...

Again, I'm not disputing what Mark has experienced, I'm just writing what I have experienced and noting that if someone does have the energy capacity to run a unit for a longer period of time (twice as long in most cases), then a lower capacity unit (7-8 gal/hr) energy-recovery unit can make sense...
{Add a couple grand for the fully-automatic MPC-5000 system for the little Ventura and it does add up a bit....but then you're not comparing apples to apples....and aside from a couple defective salinity probes, I've never had any problems with any of the "automatic" functions....but if I do, there is ONE toggle switch to flick and then she's in manual mode.....
I'm not sure about all those guys Mark has met who are "constantly fighting them", but perhaps they have some "installation issues" etc. that may be causing these troubles as I have had my Spectra for >6 years, > 12,000 miles
offshore (incl two Atlantic crossings) and haven't found these issues at all...}
I'm not disputing what Mark has experienced, and take him at his word, but rather, I'm just saying that there are a couple different ways to compare things....
And, if take into account that you CAN use a smaller capacity energy-recovery unit (running for a longer period of time), then you may find that the "cost difference" to be slight....
Understand that I still feel that YOUR watermaker choice should be based on YOUR application/use, and on YOUR on-board energy generation/storage capability.....
I'm just saying that IF you do have adequate energy capacity (solar/batteries/etc.) then a smaller capacity (7-8 gal/hr) energy-recovery unit is not anymore expensive than a larger capacity AC-powered unit, and it CAN be a viable choice.....(it works well for me!!)
And, yes, having the energy to run a watermaker (whether DC, AC or engine driven), IN ADDITION to your other systems on-board, is very important and should always be considered.....
Solar Panels
Towed-Water-Generator
Battery
Watermaker
Also, in addition to running it when
offshore and in the
Caribbean, I have run my unit in the
Bahamas (mostly the
Exumas, Berrys, and Long island) and have not found any issues with clogging filters....but since I'm in a bit deeper water (as I draw 6.5') and have my RO raw-water intake ~ 2' - 2.5' below waterline, I haven't noticed problems with silt in the filters nor had any issues with sea grass, etc. there in the
Bahamas....
But, right here at my
dock in S. FL I have lots of silt in the water (I'm about 2 miles up river from the St. Lucie inlet) and my pre-filters will start to fill up with silt in just a few hours, so I DO understand Mark's issue when in areas of high silt....
Fair winds to all....
John
s/v Annie Laurie