What to do about Water? tankage, requirements, watermakers.... etc.

[CapnK]

Ah, OK, I see- thanks Greg, and a Grog. :)

[Shawn T W.]

Eric,

I read were many  'authoritative' sources recommend a gallon per day per person.  That can ba an awful lot of water!

  I have heard that adjusted down to half a gallon, (but would prefer not to adjust).  Little things like rinsing my face, and other 'extravagant' uses of water don't seem like too much to ask.   ;)

  I was sailing yesterday, and looked down, and came up with another idea.... my cockpit drains have sea cocks on them that could be closed under the right conditions to allow a few inches of water to accumulate in the cocpit for rinsing clothes.  If your cockpit drains were not connecte4d to seacocks (many are not) you might be able to use those simple flat rubber drain covers that some people use in bathtubs to accomplish the same purpose.

I know this was posted quite awhile ago . . . but . . .

Is this water for other than consumption? Then it may be OK! However . . .

We should drink about .5 oz of water per day per pound of body weight. Here is a cool calculator http://www.csgnetwork.com/humanh2owater.html If you drink coffee . . . you will need to drink TWICE as much water just to stay even, as coffee "uses" your "on-board" water, and cause you to "P" more!

Shawn

[chris2998]

how much does water makers way?? I thought you can get some that are pretty small

[AdriftAtSea]

A PUR watermaker 40E weighs about 25 lbs.

[nowell]

Personally, I don't mind the weight or the power consumption of a water maker. Consider, that some decent water makers, can make, what, (lets be on the VERY conservative side) 5 gallons an hour. Around 1.5 watts per hour (or 17 amps per hour).

Figure most of us average around 60 gallons? Basically, it would take half a day, and about half a charge on any decent deep cycle batter to top off?

Obviously, this isn't perfect math, just continuing the conversation. Between wind/solar, there is no reason we couldn't use a solution like this on our boats. Most of us have the mentality of water conservation, so its not like we would be using this on a daily basis.

Altho, it does open the argument of "Since I have a water maker on board, I might as well take that 2 hour shower!".  ;D

Just have to avoid that mentality. I guess what im saying, is that, as like our computer thread, as technology gets better. The units get smaller and more effecient.

Used http://www.spectrawatermakers.com/ as my source for the numbers above. Looking at the Ventura 150.

[Auspicious]

I'd offer that independent of cost, the appropriate metric for a watermaker is energy per unit product (Ah/gal or Wh/gal).

I have begun compiling a spreadsheet that captures the relevant information. I'm still experimenting with metrics that incorporate capital and maintenance costs.

The peak efficiency around 1.2 Ah/gal seems to come at the 300 - 400 gpd range. You pay for that -- 1.4 Ah/gal is about 30% cheaper and 2.2 Ah/gal saves half of original purchase price. I did include flushing in the calculations but made some other assumptions that may differ for you. The assumptions are documented in the spreadsheet so you could tune the analysis to your particular scenario.

I am happy to share my spreadsheet with anyone interested and only ask that if you add data you share it with me so I can keep the total up to date.

[AdriftAtSea]

Nowell-

You might want to try re-reading the specs for that watermaker:

POWER REQUIREMENTS
Pump Horsepower    1/8    
Amp/Hr per Gallon (12 VDC)    1.4    
Watt/Hr per Gallon    17    
Current Draw (12 VDC)    9 Amps

Your numbers are WAY OFF BASE. 

You might also consider how much space the Ventura 150 takes up.  The main unit is about 2.5' x 1' x 1'.   The water pre-filter is basically .5' x .5' x 1', and the feed pump is .5' x .5' x 1' as well. 

I'd rather get the lower capacity Pur/Katadyn PowerSurvivor 40E.  It is about a 25% of the capacity, but has enough capacity to handle two people rather easily—two hours giving 3 gallons or so—and can be manually powered in an emergency.

You also have to consider how often you would run the watermaker, since they really need to be run about every few days or you have to pickle the membrane.  How long does it take you to go through 60 Gallons of fresh water?? If it takes you two weeks to do so...which is about four gallons per day.  If you ran the PS40E just three hours a day, you'd keep up with your usage and only be using 12 amp-hours per day.   Conversely, you could manually operate it and use no electricity whatsoever. :)

[nowell]

Thanks for clearing that up  ;D

[Joe Pyrat]

I don't have a water maker, just 80 gallons of storage in two custom stainless steel tanks forward, but I do remember an article in Cruising World, I believe, a few years ago about making your own water maker using PVC tubing and filters and other components you can purchase separately.  If memory serves, not only did it out perform all of the ready made units it didn't draw much power and could be custom made to fit in out of the way places because it was not in a box but could have components located in various places around the boat.  I'll try a search on the CW website and see what I can find.

[AdriftAtSea]

No charge... anytime... :)

Thanks for clearing that up  ;D

[skylark]

I'd offer that independent of cost, the appropriate metric for a watermaker is energy per unit product (Ah/gal or Wh/gal).

I have begun compiling a spreadsheet that captures the relevant information. I'm still experimenting with metrics that incorporate capital and maintenance costs.

The peak efficiency around 1.2 Ah/gal seems to come at the 300 - 400 gpd range. You pay for that -- 1.4 Ah/gal is about 30% cheaper and 2.2 Ah/gal saves half of original purchase price. I did include flushing in the calculations but made some other assumptions that may differ for you. The assumptions are documented in the spreadsheet so you could tune the analysis to your particular scenario.

I am happy to share my spreadsheet with anyone interested and only ask that if you add data you share it with me so I can keep the total up to date.

Please include things like noise, heat and vibration caused by a watermaker, if those can be properly quantified.

[Auspicious]

I left out the part where looking at the data keeps convincing me that I really don't want a watermaker. <grin>

[s/v Faith]

I left out the part where looking at the data keeps convincing me that I really don't want a watermaker. <grin>

  Like I posted earlier in this thread, I actually went through BUYING one before I decided I had no interest in having one aboard.

I think there is a greater cost then the dent in the energy budget, the weight, the space, and even the cost.  I believe that the greatest liability is the added stress and complication that a watermaker brings. 

  Not dozens, but hundreds of reports of people altering their trips and spending much time and money working on, trying to find people to work on, and chasing expensive parts for watermakers.  If I were going to spend a year in the Gulf of California I might think about it.... not for the tropics or most of the areas that I want to cruise in.

  Just some more grist for the mill.

[CapnK]

All of the above drawbacks, and the one not mentioned - PRICE -(watermakers are hugely expensive, as are the parts - when you can get them, especially "out there"...) - are the reason I find this idea so interesting...

It just makes sense that it would be easier (and therefore use less energy and be more efficient) to get fresh water out of the air, than to create it from saltwater. No filters/membranes/pumps/pickling needed, just make some condensation, and catch it...

[Auspicious]

If you look at the space a watermaker would take up and consider putting in some more water tankage of the same volume the watermaker starts to look even less sensible.

On the other hand, I know one fellow who has to accommodate a long-haired wife who washes her hair every day. If a watermaker is what it takes to go sailing then fine, but a think a couple of hundred gallons of water tankage would go a very long way.

[AdriftAtSea]

Then again, if you look at it from a weight standpoint, a watermaker makes a lot of sense for weight sensitive vessels, like multihulls. 

A Katadyn/Pur PowerSurvivor 40E weighs 40 lbs. with all the accessories, spare filters, supplies and such.  That's only about the weight of five gallons of water.  Assuming you can power it via renewable energy, say solar or wind, then it becomes a huge weight savings over the long run.  100 gallons of water is a bit over 800 lbs., and takes up 13.4 cubic feet. 

For a multihull, especially a trimaran, a watermaker might make a lot more sense than additional tankage, provided enough water is stowed to provide supplies in case of a watermaker failure.  This is due to both the stowage requirements of a large quantity of water and the weight requirements... since trimarans tend to have less stowage available than do catamarans, and all multihulls are fairly weight sensitive.

[nowell]

How do you guys factor in costs in areas where you have to buy water, or where you are taking a chance on drinking water? Some cruising areas might even have to import potable water themselves, so your now paying a premium?

What is the cost vs changing your cruising area/plans? While mostly a rhetorical question, I guess thats when you start factoring in what a water maker means to you personally.

[CharlieJ]

How do you guys factor in costs in areas where you have to buy water

I just consider that a part of the cost of cruising. You simply plan for it as part of your budget. Along with other fees, such as entry fees ( like $150 for our size boats for the Bahamas) mooring fees where you must moor, etc.

If they have to import it, then you must be prepared to pay the piper so to speak. For another example, ALL water in the Keys is either piped in via that one big pipeline, or rain caught. So you COULD be charged even stateside.

Not a big deal really.

Oh, and you would use filters if the water was questionable- or not fill there. ALWAYS a good idea to sample the water anywhere before you fill tanks. I used to make it a practice to NEVER fill every tank from a single source all at once. Fill one, then if that's ok, THEN fill the rest, maybe a day later.

[nowell]

Maybe im just paranoid from my time in the service, where even a mouthful from a "supposed" clean source in triple canopy had more living organisms than some small countries.

Most of the questions I pose are purely to keep the conversation going as alot of people have not really had to deal with bad water, or the outcomes of drinking said water.

Granted, I hate looking at the water tables for city supplies, some of the poop they put in is absolutely sick. I just love playing devils advocate, and I think its spawning great conversation!

[Joe Pyrat]

I emailed the Clorox people about treating water onboard and this is their reply regarding drinking water.

To purify the water for drinking, we recommend using 1/4 teaspoon of Clorox Liquid Bleach to one gallon of water, let sit for 30 minutes.  After this time there should be a slight chlorine odor to the water.  If the slight chlorine odor is not present, repeat the dosage and wait 15 more minutes.