Water Maker (Desalinator)

[Woodland Hills]

We are happy with our Sea Recovery unit: automatic operation and 30 gals per hour with automatic backflushing. The diaphragms are at least 10 years old and have never been pickled or preserved, yet it still works just fine and makes clean pure water. It gets used a lot in clear water and never in dirty water like the ICW or Chesapeake Bay so it’s been a few months since we last ran it. Are we doing something wrong to have it work so long and so well while avoiding all the steps others have said are mandatory?

 

[Lepke]

Manual watermakers are not necessarily better, just cheaper for people that don't think they can afford one. I was a little surprised to see the push button equivalent of my 40gph costing $17,000. Now that I've been thru the process a few times, I think I could do it for $2-3000.

My last system used a belt drive hp pump on a generator. The problem was the generator didn't have enough electrical load most of the time I was making water. My hp pump now was bought at a farm supply and doubles as a 2800psi pressure washer, Cat pump and 5 hp motor, about $800. I could run 4 membranes, but don't need to make 80 gallons/hour.

 

[BYNW]

The La Conner area has lots of turbid water from the river outflows.

 

[Fletcher500]

I recently drove through some kind of heavy contamination in the water. A portion of the trip was in the dark, so I never saw it. The sea strainers for the Main, Gen, and Seakeeper all had black residue, and I could not see the strainers through the site glass, even with a flashlight. I thought it was oil, but it didn't smell like a hydrocarbon. Cleaned all of them out and things appear to be normal now.

Anyway, I know these WM's have excellent filtering systems, but I was wondering what that would do the system? And if any of the particulate gets through, its going in to the main water tanks.

Its never happened to me before, so the chance of recurrence are likely low.

Anyone ever deal with heavily contaminated water like this going through their WM?

 

[ben2go]

Other than sediment and dissolved solids, what's the other issues for watermakers in places like the ICW, rivers, and lakes? Prefiltration I would think is a must for any WM. I think it was posted over on the BLF that 30 microns were recommended for prefiltration.

 

[ksanders]

Other than sediment and dissolved solids, what's the other issues for watermakers in places like the ICW, rivers, and lakes? Prefiltration I would think is a must for any WM. I think it was posted over on the BLF that 30 microns were recommended for prefiltration.

We have a 20 mcron that feeds a 5 micron.

The 20 is the one that gets plugged up.

Easy to see, just look at the low pressure gauge once in a while. The high pressure pump does not need much if any pressure to operate.

 

[ben2go]

Thanks, ksanders.




I found a pretty good PDF on DIY watermakers. I'm including it here.

 

[motion30]

Check out seawater pro out of Fort Lauderdale they have several different versions from 12 volts to 110 volts. Basic system with little to go bad and the factory support is exceptional

 

[Lepke]

In the winter I make water on the Columbia River. And I've had the tank water tested many times. I use 4.5 x 20 big blue filter housing because the large filters last seemingly forever. At least a year with heavy use. I have a 20 and 5 micron washable filters and then a 1 micron sediment filter, a granulated carbon filter (removes odors, smells, chlorine), Carbon Block filter (removes more tastes, odors, chemicals, VOCs) before the membranes. After another carbon filter for tastes and finally a UV sanitizer light.

I have great tasting water, and in tests the only element found was a trace of copper - I have copper plumbing. No lead, iron, mercury, nitrate, nitrite, chlorine, fluoride, etc. The test is taken from tank water.

The first 2 mud filters catch almost all things in the water because the following 1 micron lasts for more than a year. In fresh water the TDS is 0 or 1.
A membrane will remove 99% of dissolved minerals, heavy metals, mercury and thousands of other elements. But you have to run at least 1 prefilter or you'll plug the membrane.

 

[Fletcher500]

I have a Dometic XTC 1800 sea exchange with a spot zero 2000. I can wash the boat with it and I don’t need to wipe it down, no spots.

Do you take suction to do the boat wash down from your tank, or directly from the RO system?

Did you add a separate pump that feeds a hose to spray the boat down?

 

[Bigsfish]

Fletcher. I have two spigots (one in the bow, one in the stern) that connect to the water tank and water pump. No extra pump, just using the stuff that is there. Everything come from the water tank. I know it pisses some boaters off when we hose down during cocktail hour.

 

[w8n4sun]

I've had and used one of these in the past, very happy with the results and easy to use and pickle. Maybe an idea if you don't want a permanent installation?


https://www.rainmanusa.com/

 

[Fletcher500]

Fletcher. I have two spigots (one in the bow, one in the stern) that connect to the water tank and water pump. No extra pump, just using the stuff that is there. Everything come from the water tank. I know it pisses some boaters off when we hose down during cocktail hour.

I like it.

We recently returned from a 3 week trip to one of the Channel Islands. 200 gals of tankage, and then we had to bring 60 - 1 gal containers of water, and that barely got us through it while in rationing mode.

The ability to make water for consumption, grey, black, and to rinse wetsuits and gear is the primary reason we need a WM, but hosing the salt and grime off the boat every few days would also be an added bonus.

 

[Bigsfish]

We use to go for three weeks on the boat with 60 gallons of water, yeah we showered in salt water and rinsed wit a very small amount of fresh, unless it rained. Now we use as much water as we can. Best part is there is nothing to do but change the first filter every two years, everything is automatic except telling if how much water to make which is via a touch screen.

 

[dhays]

A little watermaker background is needed folks. This will help folks understand what is happening.

Thanks Kevin, that is the kind of over view that really helps someone like me.

Like the OP, I would use a watermaker infrequently. At this point in my life, maybe a couple times a year. The PO of my boat had a watermaker installed after he bought the boat, but removed it after finding that he didn’t use it often and didn’t want to maintain it.

The problem is that when we have 5 folks on the boat for a week, we can easily go through the 350 gallons of fresh water that we carry unless I enforce very strict water use restrictions. So for me, while it might be infrequently used, it would be very helpful for those times. I’ve looked at the Cruise RO system in the past and it is very attractive.

 

[dhays]

Exactly why I mentioned my cruising habits....for a TF reality check

Now I have not heard this recommendation before....makes a lot of sense and will impact my view of the installation. Manufacturers rec a dedicated through-hull b/c the flow is high and could starve another draw on a shared through-hull. My initial thought to save a haul-out and new through-hull was to T off one of the main engines raw water through-hulls b/c I guessed I would be making water when anchored with the engines off. Learned a lot from you on this one....

I have thought about this before. When I would use a watermaker is primarily when I am up in BC. Water can be hard to come by. However, when I move from one location to another I am going to through relatively clean raw water. I wouldn’t mind running my genset while underway to power a watermaker if needed. Since the PO did have a watermaker installed before, I have an unused thru hull available in the ER.

 

[ksanders]

Do you take suction to do the boat wash down from your tank, or directly from the RO system?

Did you add a separate pump that feeds a hose to spray the boat down?

I re-purpoused my throughhull that was for the washdown pump.

Now i have no seawater washdown, and love the fact that when I spray the boat off it’s with nice salt free water!

 

[Bigsfish]

If you have unlimited fresh why do you need a salt water wash down?

 

[ksanders]

If you have unlimited fresh why do you need a salt water wash down?

Yep, nothing like pulling into a nice scenic anchorage and having your windows all salt crusted from the open ocean.

A quick spraydown with fresh water and your view is restored.

What I found is that once you get a watermaker, you quickly forget all the tricks you learned about water conservation.

No more navy showers. No more quick rinse for the dishes. Need to do a load of laundry then you do a load of laundry.

I have a 60 gallon and a 140 gallon potable water tank. While away from the dock I keep the 140 as a reserve and live off of the 60 gallon tank, which is replenished daily using the watermaker during normal generator run times. I’m guessing that I use close to the full 60 gallons a day.

Here is another trick. If I’m in a situation where I want to run up on plane I’ll use up the 140 gallon tank to lighten up the bow of the boat by almost 1200 pounds. This gives me an extra knot or two of speed. I’ll then re-fill the tank on the other side.

 

[Bigsfish]

Yeah, I boated for many many years and never wanted one, now I wouldn’t be without.

 

[Woodland Hills]

If you have unlimited fresh why do you need a salt water wash down?

We thought the same thing until we arrived at the Chesapeake Bay and began anchoring in mud! The water is cloudy enough to clog the prefilters on a daily basis so we have stopped making water. Unfortunately we don’t have a saltwater wash down at the pulpit and we are having to run a hose from the cockpit to the bow. Adding a seawater outlet at the pulpit is high on the winter to-do list now.

 

[ksanders]

We thought the same thing until we arrived at the Chesapeake Bay and began anchoring in mud! The water is cloudy enough to clog the prefilters on a daily basis so we have stopped making water. Unfortunately we don’t have a saltwater wash down at the pulpit and we are having to run a hose from the cockpit to the bow. Adding a seawater outlet at the pulpit is high on the winter to-do list now.

Some of this challenge might be installation related. Not the time it takes to clog a pre-filter but the time it takes to change one.

All I have to do is open my lazarette hatch and the filters are right there. It takes all of 90 seconds to change a filter, and if i had to swap out the 20 micron one every day and wash it out for tomorrow that might take 5 minutes. Well worth it IMO for a days worth of pure clean water.

 

[Bigsfish]

Having not been to the Chesapeake in decades are you say there is no clear water?

 

[sunchaser]

I have thought about this before. When I would use a watermaker is primarily when I am up in BC. Water can be hard to come by.

Not arguing against a water maker, but south of Cape Caution water is plentiful. Between Cape Caution and Prince Rupert, with a bit of planning good water can be found especially if you have 350 + gallon tankage.

 

[ksanders]

One other great thing about a watermaker is having fresh pure water to drink every day and not having to drink “tank water” or buy bottled water.

I routed the “test” output of my watermaker to a spigot on my galley sink.

When I run the watermaker I fill up two BPA free gallon containers from the spigot and put one in the fridge.

Ice cold, fresh water to drink.

 

[Bigsfish]

Even if water is plentiful and free it tastes so much better from a water maker I will never be without one. Showering in soft water is a real treat.

 

[dhays]

Not arguing against a water maker, but south of Cape Caution water is plentiful. Between Cape Caution and Prince Rupert, with a bit of planning good water can be found especially if you have 350 + gallon tankage.

Yeah, the times when water has been tight is when we have our family with us for week in the summer. Showers are the big consumer. We can do it, but we do have to conserve water. I end up being the water Nazi.

We also find we never can wash the boat down. So if a crossing is a bit rough, we are stuck with the salt on the boat. Until we return to Puget Sound. Certainly not a tragedy and with 350 gallon capacity we are doing better than many.

 

[Fletcher500]

Good input, Thanks.

I had a through hull installed last year, and plan on the WM install this Winter.

Being in EQ country, our boat is our family meeting place to gather If the big one hits. Having the ability to make water if the utilities are down for awhile is another positive.

 

[Cheechako]

Any comments from the watermaking guru's about drawing the raw water intake from the same through-hull as another service such as your generators cooling water intake?

 

[Russell Clifton]

I'm not a guru but you will be using the generator to run the water maker. Both will be drawing from the same source at the same time.