Watermaker advice required

[chrisb]

Suggest you look carefully at your power requirements and how you will meet them and then your battery capacities.Think laterally if you are planning to live aboard becauses your power usage will probably be greater than you anticipate especially if you move further afield and to hotter climes.
Then decide if you have a need for a diesel genset or not.
This will decide for you whether or not you go for engine driven or AC watermaker.
Which ever you choose you will use more water than you anticipate
12V is unlikely to power a useful system without huge battery bank capacity.
We have used a Dessalator D60 for 3 years cruising and have found it extremely reliable
Echotec have a good reputation and can be purchased VAT free in Trindad if you pass that way
If you go anyhere very hot aircon is a very wise add on possible with a genset for less money than an Ebberspacer heater

 

[Just Cruising]

We purchased a Dessalator Duo 65 from Advance YAcht Systems and havent looked back. Great service, great back up service, component replacement easy as you install it where you want it and altho it takes 4o ah to produce 60ltr/hr we run it when we are motoring if we have to duting the day. We can also replace the lost amps with solar or windgen over the day and it gives us the freedom we need to keep away from marinas and harbours pouplated by charterers who cant park. Not cheap but worth it for the freedom over time.

 

[Neil_Y]

My experience for what it's worth is that we had no issues getting water and carried a good back up of bottled. We never felt like we had any shortage of water and having a water maker never crossed our minds. I've spent two years cruising from UK to Venezuela, but am back now running a business I set up as I got bored cruising! Sometimes I wish I'd kept the boat.

This water maker of you are sure that's what you want is a very nice piece of kit, http://www.atlantismarine.co.uk/Aquafresh.asp

On the power useage we had excess power just using an Aquair 100 towed/wind gen. We had no led lights ran an Isotherm fridge 24/7 as well as St600 autohelm 95% of sailing time and laptop/radio nav lights. The only time we were too hot in these regions was when the boat was ashore in Trinidad for a bottom paint/epoxy keel job.

Have a good trip.

 

[BeBe]

We purchased a Dessalator Duo 65 from Advance YAcht Systems and havent looked back. Great service, great back up service, component replacement easy as you install it where you want it and altho it takes 4o ah to produce 60ltr/hr we run it when we are motoring if we have to duting the day. We can also replace the lost amps with solar or windgen over the day and it gives us the freedom we need to keep away from marinas and harbours pouplated by charterers who cant park. Not cheap but worth it for the freedom over time.

Yes, ditto on Dessalator. We have the D160 - 160l/hr. The pumps and other parts that Dessalator chooses are some of the best available. Like you said, not cheap, but one of the best available...and BTW, the membranes Dessalator uses along with all of the other parts except for the control module can be purchased on the open market. I think this says something about the Dessalator vs some other brands.

Bill

 

[Bilge Rat]

This website http://sublimesustenance.files.wordpress.com/2012/03/how-to-build-your-own-watermaker.pdf gives a more detailed insight into the process and parts required to build your own watermaker, also gives sources for most parts.

In the UK, Screwfix are good for pre filters and filter housings, asap-supplies are good for nylon high pressure hydraulic steering system piping and fittings that are ideal for the high pressure side of a watermaker system, desal.co.uk are a good source for membranes and pressure vessels, as well as bulk supplies of pre-filter cartridges. Finally CAT Pumps have a UK dealership. Google will find all the above as well as many alternatives - you need to do a bit of work yourselves!!!

Thanks for the link, Chris. This is a brilliant article and we really like the idea of installing the parts where most convenient and knowing exactly how it all goes together - not to mention the effect on the price tag!

 

[Fizzwizz]

Please remember to turn your water maker off while discharging your black water holding tanks

 

[ean_p]

minerals?

as the output of the RO unit is largely de mineralised, are there any medium to long term health issues here? Is there a need to supplement some minerals?

 

[noelex]

Our Spectra has made 30,000L so far without any problems.

The first thing to decide with a Watermaker is how you are going to power it. The energy recovery units like Spectra use significantly less power.

The spectra spare parts are more expensive, but the units are very reliable so you don't need them very often.

 

[BeBe]

as the output of the RO unit is largely de mineralised, are there any medium to long term health issues here? Is there a need to supplement some minerals?

Good Question, see the attached offered by Dessalator. We do not have this, but I assume there may be use for it if you never drank anything except your water maker water.

Bill

 

[Fizzwizz]

as the output of the RO unit is largely de mineralised, are there any medium to long term health issues here? Is there a need to supplement some minerals?

Pure water is highly reactive and quite corrosive. Its pH becomes more acidic. There is an associated health risk with long term consumption of more acidic water, including cancers. Regions throughout the world with less acidic water live longer.

Something else to we wary of when drinking filtered water, virtually all synthetic chemicals are molecularly smaller than water and, therefore, cannot be effectively reduced by reverse osmosis. Reverse osmosis does not remove many poisonous contaminants which have no bearing on TDS readings.

... Fizz

 

[noelex]

Pure water is highly reactive and quite corrosive. Its pH becomes more acidic. There is an associated health risk with long term consumption of more acidic water, including cancers. Regions throughout the world with less acidic water live longer.

Something else to we wary of when drinking filtered water, virtually all synthetic chemicals are molecularly smaller than water and, therefore, cannot be effectively reduced by reverse osmosis. Reverse osmosis does not remove many poisonous contaminants which have no bearing on TDS readings.

... Fizz

Pure water has a completely neutral PH of 7.0.
Sea water is slightly more basic, so presumably is a Watermaker output.
NaCl is very small! Just 2 atoms. What synthetic chemicals are smaller?

 

[Juniperskip]

Installation

We also wax lyrical about our Dessalator 60, in line with the comments so far. What we did do was have a tap at the sink installed with a diverter valve under the sink. This enabled us to divert the tank water feed to the sink to fill personal water bottles for long passages. V useful...

 

[Fizzwizz]

Pure water has a completely neutral PH of 7.0.
Sea water is slightly more basic, so presumably is a Watermaker output.
NaCl is very small! Just 2 atoms. What synthetic chemicals are smaller?

Sea water is more alkaline (base is a property given to solids), water with dissolved salts is more alkaline, therefore pure water is more acidic. pH is a logarithmic scale of free protons available for ionic donation. The neutral pH is by it's definition the pH of water. it is a comparison of tendency to donate protons 'compared" to water. Neutrality means nothing except that a substance with a pH of 7 will not donate or accept protons in pure water. It does not imply inertness. Water, by its physical properties, as well as its ionic ones, is highly reactive which is why it is the medium for nearly all chemical reactions. pH of blood plasma is about 7.4 if you're looking for a biologically "neutral" pH.

Reverse osmosis does not filter out NaCl, which would have a molecular size comparable to water if isolated. Reverse osmosis filters out large metal aquo complexes [Na(H2O)x]+ which are larger than many poisonous molecules (even organic ones)

... Fizz

 

[noelex]

RO watermakers will reject any molecule larger than 14-20 nanometers.
Do you still feel this statement is correct?

virtually all synthetic chemicals are molecularly smaller than water and, therefore, cannot be effectively reduced by reverse osmosis.

 

[Fizzwizz]

No, I didn't mean to say that (though clearly did). Synthetic molecules aren't smaller than water molecules. I meant synthetic molecules are smaller than complexes dissolved in water.

Without looking, I don't know how these sizes measure up to molecular sizes of small organics like toluene which are carcinogenic. Given a good filtration system shows post filter TDS of 250 you can infer that this will be mainly composed of molecules smaller than ionic complexes