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09-04-2013 09:13 PM
Re: Water Useage/conservation Cruising

Originally Posted by outbound View Post
Do you really need to hold made water in a separate tank and test it before dumping it into your regular water tank(s)? Is dumping the first few galleons into a small container and testing that sufficient? Would appreciate opinions. Have two 100g tanks.Thanks.
What I am going to fit to mine (have seen it on several other boats) is a by-pass from the membrane-to-tank line that comes to a tap in the galley. The WM runs for a short while and a sample is taken, tested for TDS and when they are at an acceptable level the by-pass is returned to the main tank. Water quality is very unlikely to change when the WM is running.

FYI this is the basic schematic of a WM that can be installed in modular form:

Essentially a low pressure pump draws water from the sea through a strainer (this could be your normal domestic water supply pump), delivers it through a carbon filter to a HP pump. The HP pump circulates the water freely through the membrane tube with nothing going through the membrane (no fresh water is made) and the sea water returns to the sea.

When the pressure regulator valve is partially closed the pressure builds, the gauge allows you to regulate to 800psi and the water starts permeating the membrane. If the pressure gets too high, the blow-off valve vents the excess.

On the other end of the membrane tube is a flow of fresh water to the tank/test valve. With the valve turned to test sampling can be done. When the sample is good the valve is switched and the water goes to the tank. The brine that by-passes the membrane goes back to the sea. It will probably be necessary to put another blow-off valve in the fresh water line because if the tap in the galley is closed and the valve is switched to "Test", the pressure in that line will build to system pressure (800psi) which would not be good.

Like I've said, this is not magic, just common sense.

Hope this is helpful
08-30-2013 08:21 AM
Re: Water Useage/conservation Cruising

Originally Posted by Bene505 View Post get the fastest flow that still lets gravity hold the hose in place, instead of the hose acting like a water-propelled rocket......
Great post, Brad. This comment made me thnk to mention that I bought a cheap plastic shutoff that screws onto the male end of the hose. Therefore, the water can be fully turned on/off, while up on deck. Worth throwing one in the cockpit table for when filling from transient docks.

08-30-2013 05:04 AM
Re: Water Useage/conservation Cruising

Great thread, Brian. Here's our water usage.

We have 1,000 liters, or 268 gallons, not counting the 12 gallons in the water heater. Onboard we have a family of 6, a dog, and a beta fish. ("Flo" doesn't actually use much water, she just sits there in her bowl, which fits nicely in the sink when we go sailing.) Our water lasts 3 weeks with most showering done on shore. We do drink from a refilled plastic water bottle brought from shore, and generally spend most of our day on shore, where much of our water drinking takes place.

The area where we like to anchor is on a lake, at the farthest end from the entrance to the lake. So there isn't much water turnover from the tide, and there are recent, tested-as-marginal issues with cesspool run-off at that end of the lake, especially after rainstorms. It's not closed for swimming, but it's been a hot topic in the papers.

So when we step onto the boat from the dinghy, everyone quickly rinses their lower legs and feet with the transom shower. And we rinse the dog's 4 legs and paws, cupping water around his paws to get all the salt and sand off. The fresh water rinse keeps our feet/skin happier and there is a LOT less sand on the boat. Also, the dog's fur stays clean and it doesn't feel disgusting when he rubs by your feet/legs. (He likes to hang-out under the salon table. And he is otherwise underfoot.)

We wash dishes with fresh water. Everyone knows to not let the water run, but twice this summer we heard the pump running, which lately means the transom shower is off at the shower head, but not at the knob. Like Smacky drinking all my tequila, it dribbles a little bit in that mode.

Last year we didn't do as much foot-washing, but we took more showers on board. It seems to be equalling out.

This works out to 2 gallons a day, if you count the dog as half a person.


We have 4 tanks, (located just like the quadrants on a graph):
1) 166 liters (forward starboard)
2) 166 liters (forward port)
3) 166 liters (amidships port)
4) 500 liters (amidships starboard)

We use them in the order 1, 2, 4, 3. This is reduce forward weight early, and then to save a small tank for the same reason Brian mentioned. When we have 166 liters left, we know to start thinking about getting more. (And half-full tanks have a lot of "free surface" which decreases stability.)

I can tell by the list of the boat when tank 4 is getting empty, and sometimes some of the other tanks too.


We have four heads, each with a combination sink/shower head, but one head is used like a closet, so three are in use. We have the galley sink and the transom shower. We have a crew's quarters sink but it is never used, and when storing sails, etc., I make sure nothing is catching on that sink's faucet. So there are really 5 places that water could be running. We leave the pump breaker off when we go ashore, unless I'm certain that fresh water isn't leaking out anywhere. It's nice to have the water pressure ready-to-go when we step back onto the boat and want to rinse our feet.


We use powered milk, using water from a shore-refilled water jug. But now that we have the kinks worked out of our electric fridge and freezer, and since we now have ample solar power, we just started buying fresh milk. That's probably not worth mentioning, but it sure is nice.

Last summer we had a water filter on the faucet, and would freely drink the boat's water. This summer is more about the jug or two brought from shore. (I didn't put a filter on this summer.) In the spring we do an 8 hour Clorox shock, immediatly followed by (partially and fully) refilling and (thoroughly) draining each tank several times.

At the beginning of the summer we stock-up on 2-liter bottles of ginger ale and other sodas. I want my young crew to be familiar with the taste of ginger ale, in case they start feeling queazy.

We sometimes have an emergency gallon next to the starting battery down in the bilge. Since we are very coastal, we never seem to be more than 2 hours from a harbor. Once we start going offshore, I plan to significantly increase the jug storage.


As for collecting rainwater, we have strings of monofilament installed 6 inches above the spreaders, which stopped the birds from pooping on the deck. But I'm still not ready to start collecting rainwater. The anchor comes up a bit muddy and I don't invest the time with a bucket or the saltwater washdown hose to keep the deck clean enough.

Reading this thread has helped me realize that our stack-pack is designed with material that holds water. When it rains, it even fills with water. I haven't drank the water run-off from it yet mainly because I find bird eggs in there every spring. We ought to clean it before trusting the water, but it's not a high priority as there is water available nearby.

A true cruiser would probably eat the eggs.


We buy our diesel from the same place we refill our water. I try to buy $100 or more at a time, and once bought $350 worth. He is reasonably priced and I want to make sure we are welcome to come by and refill the water tanks. We usually refill the water at night when he's closed and the fuel dock is not being used. (He knows we do this at night.) We do this so we aren't preventing him from selling $5,000 of gas to the next fishing boat that comes along. It takes about 30 minutes for "us" to refill the 4 water tanks, and he has nearby competition. The fishing boats could easily go somewhere else.

"Us" usually means me, with wet clothes from trying to get the fastest flow that still lets gravity hold the hose in place, instead of the hose acting like a water-propelled rocket.

When we do refill our water tanks when he's open -- always buying diesel when he's open -- the crew knows that we are there to fill the water tanks quickly. I let each kid buy ice cream or a candy bar or something to add to the bill and help us be a valued customer. (It's treat, and the kids usually come back with ice cream for me too, which is most appreciated.)

I believe it also helps to tip the dock boy well, and they take our garbage in the process.

08-29-2013 03:18 PM
Re: Water Useage/conservation Cruising

great discussion! very interested to follow the self-made water maker discussion.

thanks to all.
08-29-2013 02:16 PM
Re: Water Useage/conservation Cruising

George B- been going through the same exercise myself. Interestingly, friends suggest going with the Pur 80 or 40e. Katadyn version seems improvement, very common, and old enough the bugs have been worked out. We are just 2. Suspect when we turn the watermaker on it will run daily for awhile ( a few weeks) or it will be pickled. For us using a d.c system seems to make sense as we have solar/wind but hate generators. Galleons per amp seem to be about the same for all systems from what I've read from several sources. Issue I'm struggling with is whether having a day tank for made water is really necessary? Do you really need to hold made water in a separate tank and test it before dumping it into your regular water tank(s)? Is dumping the first few galleons into a small container and testing that sufficient? Would appreciate opinions. Have two 100g tanks.Thanks.
08-29-2013 02:00 PM
Re: Water Useage/conservation Cruising

I have been told by several friends that the modular, after-market parts type set up is the way to go. I installed a Spectra Newport and that was a little difficult in a 44 footer. What are the thoughts on electrical or mechanical high pressure pumps? I may have real estate in the engine compartment for a belt driven pump but it could make checking the oil difficult. Also, I am running a 120A alternator on a single belt. Would I need to go with a two belt serpentine type arrangement or could I run two separate single belts? I have also been told to go to the largest capacity possible as this will cut down the operation times – is there any real benefit? Regarding the intake through hull – can I “T” it off an existing one (like the galley salt water intake) or does it need to be dedicated (syphon valve needed?). My available real estate is all in the stern but I am worried about the excess weight there but it is close to the aft water tank. Does anyone run a transfer pump between fresh water tanks? (my plan would be to keep the bow tank full).
08-27-2013 08:36 PM
Re: Water Useage/conservation Cruising

Originally Posted by Omatako View Post
Point taken - didn't mean to offend.
'never a thought of offense,- just a clarification,- Thanks
08-27-2013 07:48 PM
Re: Water Useage/conservation Cruising

Originally Posted by CaptainForce View Post
I might have said something in an earlier post that now sounds absurd. I was against the thought of it being necessary to run water over a toothbrush before adding the toothpaste. Some had said earlier that people often turn on the tap, run water over the toothbrush and leave it running. I always use water when I brush my teeth. I just don't run the water before I brush my teeth. No one has said not to use water for tooth brushing.
Point taken - didn't mean to offend.
08-27-2013 09:45 AM
Re: Water Useage/conservation Cruising

Lots of great replies in this thread. THanks Aaron, Capt Force, Jaye, and all others for a lot of great replies and thoughts. Hope this helps some folks.

08-27-2013 09:29 AM
Re: Water Useage/conservation Cruising

Originally Posted by tdw View Post
BBQ .... I guess you have a watermaker ? How does that fit in with your water usage plan ?

Our girl has a 50 litre (aprox 12US gallons) per hour. On the hook we tend to run the donk for an hour a day anyway so at least theoretically we can cover all our water needs. We also have a collector for use with boom awning. Tanks hold about the same as BBQ's .... roughly 135US gallons.

Yes to AeV re short hair. Difference that makes is remarkable if you wash you hair daily.

Of course minimising the amount of shampoo you use will help as well. Most people use way to much and it then takes forever to rinse out.
I have pulled the plumbing and electrical and put in the space for the watermaker... but did not want to get and install until we needed it. So far a good call. Have not had a use for it yet.

Many of the places we go, I would not make water or it is easily available. For those places we would make it, we often dont stay there over a week anyways.

If we go to spend significant time in the bahamas that will likely change because the WM becomes more useful and cost effective. RIght no though, it would be pickled and a maintenance issue.

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