Which Watermaker To Choose

[wolfenzee]

Originally Posted by downunder

I did make that point.

There are increasing numbers of designers (mainly catamarans) recently who are building simple/efficient water catchment and easily 1000w solar panels into the designs without having to retrofit brackets. Cats setup for the tropics using the hardtop cockpit and saloon roofs have real advantages, here. The production builders are just now starting to consider fitting solar as an option. I think Nautitech, is one of the smaller production cat builders who have incorporated water catchment into their designs. Simple really, more difficult on a monohull.

Quote: "The Nautitech 442 is an excellent choice for sailors with the intention of going on a world tour. Its new roof with a water recovery system feeding a separate water tank increases autonomy on board.

The optional solar panels allowhttp://www.cruisersforum.com/forums/newreply.php?do=newreply&p=1127218 one to set off without having to worry about getting back to harbour."

Even a used Nauticat 44 is in the mid 6 figures (that is approaching 1/2 million $), which is out of the price range of most boaters. I paid under $20K for my boat, and even after all the bluewater/passage making/live aboard upgrades it was under $25K....

[wolfenzee]

This thread has lead me to talk to a number of sailors who have actually done extensive cruising (including circum nav)....all of them (and other people they have run across in their travels) function quite comfortably with small water makers. Including cooking, showering, drinking, etc average around 3 gpd/person (some allowed 5 but ended up using 3). If you listen to the salesman at the boatshow you will be debating between a 20gph or 30gph watermaker. Watermaters don't have to be tended, with a low draw watermaker and solar or wind generator, you can just let it run (PUR makes a sound proof enclosure...of course so could you). There was one called the "Water log", a propeller dragged behind the boat and powered the pump (like an old fashion knot log). There is no reason to spend alot more money to be able to get it done faster, your not in a hurry...where are you going.

[sailorboy1]

Maybe, but I've read lots of blogs of sailors with a watermaker and don't think I've ever read them saying they wished they had a smaller watermaker. But I'm very positive I've read lots of them saying they wished they had gotten a larger watermaker.

So I think there are 2 real camps: have a watermaker or don't. But if you are in the have camp you should ge the largest one that fits into your budget and boat.

[goboatingnow]

well the small Katadyn power watermakers seem suitable for small output, it looks like a custom membrane, anyone have any feedback

Dave

[Therapy]

Originally Posted by downunder

There are increasing numbers of designers (mainly catamarans) recently who are building simple/efficient water catchment and easily 1000w solar panels into the designs without having to retrofit brackets. Cats setup for the tropics using the hardtop cockpit and saloon roofs have real advantages, here. The production builders are just starting to consider fitting solar as an option. I think Nautitech, is one of the smaller production cat builders who have incorporated water catchment into their designs. Simple really, more difficult on a monohull.

Quote: "The Nautitech 442 is an excellent choice for sailors with the intention of going on a world tour. Its new roof with a water recovery system feeding a separate water tank increases autonomy on board.

The optional solar panels allow one to set off without having to worry about getting back to harbour."

""

St Francis has been doing it for years.

[Therapy]

Originally Posted by carstenb

While not decided yet, I'm leaning towards a 20-30 liter per hour system. these use low wattage so my solar should be able to keep up with it (in the tropics)

Again, the problem I found was that when out and about most of the time is spent at anchor in a place that is "nice". The nicer it is the longer one stays.

But.......most of the places we anchored had water that was "not good enough" for various reasons. ie. marina "yuk" in bays and rivers, silt in choppy shallow areas, too much floating grass, lots of other boats (are they really following the rules?) etc.

Running the thing every day "for just a bit" was not an option. So if water is wanted then either go to dock and take what is there or leave for a "trip" till your (small) unit filled the tanks. (over night?)

My choice now would be a higher capacity unit even if it had to be back flushed with a few gallons every week with non use.

edit> We were in a Gemini 105Mc with two 30 gal tanks. One tank lasted about 2.5 days. So since the tanks could never actually be completely filled (ever see how they sell tents?) nor completely emptied that means we used about 5 gal per day each. Lots of that was by me trying to keep cool enough with several "wipes" per day.

[downunder]

Originally Posted by Therapy

St Francis has been doing it for years.

Water catchment is so easy to do in a cat. I just picked the Nautitech as a recent example. It is standard on the australian Freeflow designs also.

Would be good if the volume French production builders it incorporated into their designs. However probably won't happen whilst they are targeting the charter market. Can hope.

[colemj]

Originally Posted by wolfenzee

This thread has lead me to talk to a number of sailors who have actually done extensive cruising (including circum nav)....all of them (and other people they have run across in their travels) function quite comfortably with small water makers. Including cooking, showering, drinking, etc average around 3 gpd/person (some allowed 5 but ended up using 3). If you listen to the salesman at the boatshow you will be debating between a 20gph or 30gph watermaker. Watermaters don't have to be tended, with a low draw watermaker and solar or wind generator, you can just let it run (PUR makes a sound proof enclosure...of course so could you). There was one called the "Water log", a propeller dragged behind the boat and powered the pump (like an old fashion knot log). There is no reason to spend alot more money to be able to get it done faster, your not in a hurry...where are you going.

We run in different circles - I have yet to meet a cruiser with a low output watermaker that did not want a higher output one. And these are also cruisers with extensive experience and circumnavigations.

I know 3 cruisers with the PUR40, which fits your definition of low amp, low output. All three of them are getting rid of it because the concept of low amp, low output just doesn't work in practice. 4 amps drawn continuously for half a day is a lot of current for not much water from a 1-2 gph machine. And getting oneself out of a low water "hole" is excruciating.

And while we are on the subject of salesman, the real crime is making you believe output. Be aware that all stated output specs are for 72*F water temp, brand new membrane and 13.8V at the pump terminals themselves. As your conditions deviate from these, the output drops quite a bit. The power is the biggie - if you plan to run off solar, there is little chance you will be at 13.8V terminal voltage on the machine. Count on 15-20% less when running at a terminal voltage below 12.7V.

So assuming 12.7V (a good assumption when running under solar), water temps out of spec and a not new membrane, you will be getting ~1.3 gph out of a PUR40 type machine. You will be able to run it for ~6 hours at that rate using solar (you will need 85W of solar just to run it alone) and it will cost you 20-30A of battery. This is not a good return or conservative use of your power.

But the point you are really missing here is that the 20-30gpd watermakers are the same price as, or less than, most 5-8 gal/day ones. And that is leaving Spectra off the table completely. This has been pointed out to you several times on this thread, but you still debate about how much money they cost just for more water faster.

Your arguments for upfront and maintenance costs are specious. Have you actually priced (for instance) a 20gph CruiserRO system and a 6gph Village Marine Little Wonder? Then go and price the 8gph Spectra if you want a shock. Any money you save on your PUR40 is going to be spent again over time in terms of membrane replacements and spare parts and rebuild kits (price them - you will be stunned - your first membrane replacement is going to cost you ~$500 more than one for a 20gph system). The 20gph HP pump can be rebuilt almost anywhere in the world by any common pump repair place. Your PUR pump will cost ~$800 to be fixed/replaced if it goes down.

When you get to the tropics, where the sun is blistering hot, the water is warm and sticky, you have both recreational gear and boat gear that requires fresh water rinsing, there is no rain for 4-6 months at a time, and the wind blowing salt from the breaking reef waves on your boat constantly, you will want more fresh water than 3 gallons per day. I drink 1-2 gallons of water each day just staying hydrated. The salt is insidious when the trades have the water vapor whipped in the air - I need to clean my eyeglasses 2-3 times each afternoon just reading in the cockpit because of the film of salt that accumulates on them. The boat is encrusted and the decks slippery.

You are also assuming that people with 20-30gpd units are using 20-30gpd. Going on about how wasteful and environmentally harmful these people are blinds you to the reality that one is often times in areas where one does not want to make water. And when one does want to make water, it is far better to make a lot of it at once to make most efficient use of the feed water quality, the power available, etc.

Can one cruise on 3gpd? Absolutely. We use ~4-5gal/day each and laundry takes a big bite every couple of weeks. But right now, our boat is covered in salt and dirt and we would like to do laundry a bit more often. Our unit runs for "free" off our solar, but doesn't leave much for recharging the batteries so we need to balance it with generator time. We will be replacing our running 6gph unit with a 20gph one in the near future. If we run the generator anyway, we may as well make a lot of water in shorter time.

The WaterLog system never worked. I have never seen a reported case of it working, and have read many reports of it not working. Even if it did work, the output was something like a gallon every 5 hrs or so.

Mark

[goboatingnow]

Great post Mark, a voice of experience. I would agree with u 100 %. Wolf misses the point. I built a watermakers , its way cheaper to use industrial components and standard HTCI vessels and a Filmtec membranes. I used an Italian piston pump typically used in farm power washers.

Dave

[settingsun]

I agree with what you say, Mark. The reason we went with an engine driven watermaker is because you'd have to have a massive solar panel array to keep the batteries at a high enough voltage to make water efficiently. Our 555 watts wouldn't have been nearly enough!!

Almost all cruisers we meet run their engines to make water with their DC watermakers. If the watermaker makes 6 gallons per hour, you have to run your engine a long time to get much water. Since ours makes 60 gallons per hour, we can fill our 140 gallons of water tanks in just over 2 hours.

And you're also so right that there are a lot of places you can't make water. We much prefer making water when we're underway. in fact, we often go out for a daysail to make water for an hour or two and then sail for an hour or two rather than make water in a questionable anchorage.

Membranes can be destroyed in minutes if there is oil, diesel or bleach in the water, which can easily be the case in an anchorage anywhere near a town or fishing fleet.

We decided to go with an engine driven system when I started pressing the salesman at Village Marine about what exact voltage was required to make water efficiently. We had lived exclusively with solar on our fifth wheel for 3 years and knew its limitations. His boss broke in on our conversation and told the salesman not to continue that line of discussion with me. "I know where this is leading" was his comment.

The dirty secret about DC watermakers is they require an engine to run their best...

Having a big watermaker like ours means our decks and cockpit aren't salty or dirty, our dinghy and kayak are clean, our bodies are clean, our clothes are clean.

All of us begin cruising after a life of cleanliness with unlimited water and electricity onshore. It's a hard adjustment to go to a life of being smelly and dirty. I sure wouldn't recommend it to anyone who hasn't outfitted their boat yet... Get as big a watermaker as you can fit (our two membranes are both 4' long).

For us with our EchoTech system, we doubled the capacity of our watermaker by adding a second membrane for $900. That's a steal!

[mcarling]

Originally Posted by settingsun

The reason we went with an engine driven watermaker is because you'd have to have a massive solar panel array to keep the batteries at a high enough voltage to make water efficiently. Our 555 watts wouldn't have been nearly enough!!

...

The dirty secret about DC watermakers is they require an engine to run their best...

Lithium phosphate batteries hold their voltage and obviate the need to run the engine to make water that is the case with other battery technologies.

[settingsun]

Cool...!

We have 4 AGM 4D batteries that cost $2,000.

Do you know who makes the Lithium phosphate batteries and what four 4D's would cost??

[mcarling]

Originally Posted by settingsun

We have 4 AGM 4D batteries that cost $2,000.

Do you know who makes the Lithium phosphate batteries and what four 4D's would cost??

You have 660 nominal amp-hours, which is about 300 useable amp-hours. Lithium phosphate batteries are nominally 3.2V, so you would use four wired in series (assuming your AGMs are wired in parallel into a 12V (nominal) bank). Lithium phosphate batteries can be safely discharged 80%, so a nominal 400 amp-hour bank would give you slightly more useable capacity than your current AGM bank. All four together would weigh about what one of your AGMs weigh, so you would be saving a lot of weight too.

I don't know where you are located, but Balqon are having a clearance sale now in the States. $258 each, so just over $1000 for the bank you need. I have no relationship to the company. Alternatively, if you want to double the capacity of your bank, you could choose 700AH cells.
Balqon - Advanced Transportation Solution

I suggest reading this thread:
http://www.cruisersforum.com/forums/...nks-65069.html
Be careful that your charging sources are suitable for lithium phosphate. All the discussion about balancing is not strictly necessary but does help to squeeze every last bit of useable capacity from a lithium phosphate bank.

[noelex 77]

I have a spectra 150 watermaker.
I don't want a bigger watermaker, if I needed more water I just run it for longer, or more often
I get 90-95% of my power from solar.

I think the different views come from different forms of power generation. If you get most of your power from a generator, or running the main engine then you need a much bigger watermaker, which will make all your water during the engine run time. Energy recovery is not important and a bigger watermaker will give you more water to use.

If running the watermaker on solar power energy recovery is vital. The gallons per watt becomes vital. Bigger watermakers do not make more gallons per watt so is little practical benefit in increasing size.

[Albro359]

We have a Schenker Modular 35 that produces 35 litres per hour (that's about 9gph). It is 12VDC and only draws 8 Amps. We have 2 x 125 litre stainless tanks which we keep full all the time.
In the South Pacific the Schenker will run easily from the power coming from our 2 x 130W solar panels. We run it every second day and keep the tanks full. No problems, plenty of fresh water for cooking, drinking, laundry and short fresh water showers.