Paolo Zini wrote:

Only for my education....
I have read somewhere about "home made" watermakers... but I don't rember
where...
I have made my google homework... :-) No result.
Do you have any reference, link, info?
I am interested in one small, simple unit for a sailboat...

Tank you
Paolo

I have a couple of pages about the one I built on my site under the
"Systems" section. http://www.rutuonline.com/html/watermaker.html

It is not small (800GPD) but with a lot of research and a little
imaginative procurement it came out just a little over $2,500. Because
it is engine driven I had to add a speed interlock to protect the system
which added about $150. I went a little overboard adding a 3 button
remote controls with digital flow and pressure displays for the cockpit
and nav station, automatic flush and electronic TDS product diverter but
if you did a basic manual 800GPD system it could come out under $2K.

My sources were all in the US but you should be able to find the similar
equipment in the EU. You might get better prices on Sehan membranes
over there than Filmtec and Bekaert Composites housings may be easier to
get than A&M.

The key is to find a good deal on a stainless or nickel aluminum bronze
head pump. Grundfos makes a titanium head pump to die for but they are
very expensive. Ideally you want a 1200 PSI plunger pump with at least
seven times the desired product water flow . The more common 3000PSI
pressure washer pumps are not as efficient at the 800PSI an R/O system
operates at. Once you get the pump there is not a lot of difference in
cost (about $450) between a 400 and 800 GPD system.


--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

I have a couple of pages about the one I built on my site under the
"Systems" section. http://www.rutuonline.com/html/watermaker.html

When I made my search, you can believe it or not, but the first place where
I searched is your page....
I definitively need new lenses... :-(

I have initially discarded the watermaker idea, because the cost, but a
do-it-youself version is appealing for a "bricoleur"... :-)

I am building a small cat (cat 254 from Fisher's plans) and i need a smaller
installation.
My main concern is the power source. The cat will have only one small
auxiliary outboard...
The possible alternatives ha
-electric.who refill the batteries? OK is a stupid question, I have the
problem anyway :-)
-small gas engine... I don't like the idea...
-odd power sources wind power generator, propeller generator...
-??
Any suggestion?

Tank you

Paolo

The laws of physics are working against you. The formula for required
pump horsepower is GPM*PSI/1460. a single 21" membrane needs a minimum
of 1 GPM at 800 PSI which means you need about 1/2 HP. That is close to
40 amps at 12V. You would need a 100 amp alternator to charge the
battery bank and make water at the same time.

I would look at the Waterlog tow behind watermaker if I were you. About
980 Euros. Not as convenient as a traditional watermaker but you can't
build one for that price, it can put out about 20 to 28 gallons in a
full day of towing and it uses no electrical power.
http://www.yach****ermaker.com/

Regardless of Jax's claim that they are fictitious, I have seen a couple
and talked to their owners. One, an Englishman doing an Atlantic
circumnavigation towed his from the Azores to St. Martin and had enough
water extra to wash down his deck every few days.

Paolo Zini wrote:
I have a couple of pages about the one I built on my site under the
"Systems" section. http://www.rutuonline.com/html/watermaker.html


When I made my search, you can believe it or not, but the first place where
I searched is your page....
I definitively need new lenses... :-(

I have initially discarded the watermaker idea, because the cost, but a
do-it-youself version is appealing for a "bricoleur"... :-)

I am building a small cat (cat 254 from Fisher's plans) and i need a smaller
installation.
My main concern is the power source. The cat will have only one small
auxiliary outboard...
The possible alternatives ha
-electric.who refill the batteries? OK is a stupid question, I have the
problem anyway :-)
-small gas engine... I don't like the idea...
-odd power sources wind power generator, propeller generator...
-??
Any suggestion?

Tank you

Paolo



--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

The laws of physics are working against you. The formula for required
pump horsepower is GPM*PSI/1460. a single 21" membrane needs a minimum
of 1 GPM at 800 PSI which means you need about 1/2 HP. That is close to
40 amps at 12V. You would need a 100 amp alternator to charge the
battery bank and make water at the same time.

My future boat is small... I must mantain a lower profile for power and
water use...
But you have also one Jacuzzi in your boat? :-)
What about a windmill power generator or towed generator to refill
batteries?
The windmill is easy to make and can be in the 1 meter diameter range.
I don't have data for the towed generator, but must be a fairly easy job...


I would look at the Waterlog tow behind watermaker if I were you. About
980 Euros. Not as convenient as a traditional watermaker but you can't
build one for that price, it can put out about 20 to 28 gallons in a
full day of towing and it uses no electrical power.
http://www.yach****ermaker.com/

I have seen it, but my lathe collect dust... I tink that you understand me
:-)

Paolo

Regardless of Jax's claim that they are fictitious,

They were fictious when I made the claim. I said they would twist off, and
that none had been delivered to the market. The manufacturer later added
adjustable fins to the unit to keep the twist at bay. The fins need to be
adjusted for the speed at which the unit is traveling in the water to keep the
twist at bay.

Reports are now that the units need a fair amount of boat speed to work, and
that boat speed a couple knots higher pulls the units from the water.