Can a Watermaker Be Used While Underway ?

[CarlF]

Maybe I just have a lucky installation, but I prefer to make water underway and have never had problems with air bubbles. Even with normal healing (I don't run it in really tough conditions).

Maybe before you go to the trouble of the tank you should see. If you have problems, add the tank. It's a great idea.

My pickup is about 2/3's aft and about a foot up from the keel root. I would guess a pickup forward of midships is more likely to have bubble problems.

As to cross contamination - never had or heard of a problem. The watermaker inlet should be much deeper than any drain.

Carl

[Tellie]

It's true watermakers do not like air. Introducing large amounts of air into the unit has a hammering effect on both the high pressure pump and membrane as the air is compressed and released. The reality is that you will have some degree of air intake into a watermaker that is run while under way. Taking into account that the feed system on board is air tight, how much air that is introduced is determined by boat design, speed through the water and location of the thru hull. Not a good idea to run a watermaker on a power boat cruising at 25knts. A sail boat cruising in most normal conditions it won't be a problem with the small amount of air introduced. Thru hull location, size, and type are usually the biggest culprits of too much air being introduced. For all but the smallest of watermakers it is best to have a dedicated forward facing thru hull set as deep as possible in the hull. Some watermaker manufacturers now require it in order not to void the warranty. It is always advisable to consult your manufacturer and tech if you plan on a self install. You'll hear it many times stated that watermakers are not rocket science. I hear it more than most. This is true, but there are a lot of simple mistakes that I see made over and over again by a rocket scientists that keep me busy.
Locating a watermakers intake close to a sink drain is not a good idea. If there was bleach of any kind (Clorox, scouring cleaners, SS cleaners etc.) coming from a sink drain located within a few feet of the watermaker intake, the dilution effect would not be enough especially for a non moving boat at anchor.

[Tellie]

Originally Posted by rickmorel

Here's what worked for us. We had a Pur 40E on the previous boat and cruised 2 1/2 years, using the watermaker about 2 of them. We currently have a Pur 80E. We wanted and want to make water in silty conditions so added another pre-filter (Lowe's $30, NOT marine $300 +) with a 5 micron filter in the second one.

After a lot of trial and error found that using our raw water pump (auto cut-off like the fresh pressure water system) and a 2 Gal accumulator feeding the pre-filters to watermaker eliminated all air problems that seemed to be more from cavitation than anything else.

The feed water is teed off the engine raw water intake, which is always under water.

We've made water offshore underway, power and sail, and at anchor. Even in our very silty bayous. Never in an industrial type area where there could be oil on the water. Oil and chlorine will quicly destroy the membrane. Of course the prefilters will load up a lot quicker in dirty water.

Speaking of prefilters, they can be simply cleaned and reused as long as they're in good shape. That is not collapsing. We changed the 20 micron once in the 2 years. We changed the 5's a few times because they're a bit harder to clean. We used the "string" type. Be sure NOT to use a paper filter.

Rick

Rick, welcome aboard always good to have new people posting.
That being said, there are some problems here. First watermakers should not be tied or teed off an engines raw water intake. Watermakers are very sensitive to flow restrictions. Most watermakers demand a lot more feed water than a small Pur 80. A raw water pump will rob even your watermaker of the proper flow it needs when the engine is running reducing the amount of your product. Pre-filters are another long subject altogether. Pre-filters do lose their filtering capabilities, most certainly a pre-filter that has been used for two years has long ago lost it's capabilities. Several spares are a necessity for long term cruising. You are right, one should never use paper filters. Nor should you use string filters either. They are very very restrictive to flow. Watermakers need proper flow. String filters are best left to your under the sink filtering devices. Proper pleated filters are the industry standard. A good pleated filter if cleaned in time, read gently rinsed, can last through about 6-9 rinses before it should be discarded. Pre-filters are NOT an area to be penny wise and pound foolish in. I am pretty confident that if you change out your feed to it's own thru hull and go back to pleated 20 micron filters your production will increase for the amps spent making water. It will also be easier on your Pur's motor and pump which will extend their life as well.

[rickmorel]

Originally Posted by Tellie

Rick, welcome aboard always good to have new people posting.
That being said, there are some problems here. First watermakers should not be tied or teed off an engines raw water intake. Watermakers are very sensitive to flow restrictions. Most watermakers demand a lot more feed water than a small Pur 80. A raw water pump will rob even your watermaker of the proper flow it needs when the engine is running reducing the amount of your product. Pre-filters are another long subject altogether. Pre-filters do lose their filtering capabilities, most certainly a pre-filter that has been used for two years has long ago lost it's capabilities. Several spares are a necessity for long term cruising. You are right, one should never use paper filters. Nor should you use string filters either. They are very very restrictive to flow. Watermakers need proper flow. String filters are best left to your under the sink filtering devices. Proper pleated filters are the industry standard. A good pleated filter if cleaned in time, read gently rinsed, can last through about 6-9 rinses before it should be discarded. Pre-filters are NOT an area to be penny wise and pound foolish in. I am pretty confident that if you change out your feed to it's own thru hull and go back to pleated 20 micron filters your production will increase for the amps spent making water. It will also be easier on your Pur's motor and pump which will extend their life as well.

Tellie, I'm new to this particular list, but have a bit over 40 years of cruising.

However, I must respectfully disagree with your disagreement of my previous and current setups. Now, I'm talking sailboat and a "small" watermaker, as you put it. As an aside, anyone not aboard a 50-foot plus power boat has no business with a larger watermaker. Heck, when we had the PUR 40 we ran into several folks who wanted to trade their 8 or 12 or 20 GPH units for ours, with them ofering money in the deal. Too much water and too many Amp Hours were the reasons. They couldn't run them enough to operate properly and smoothly.

Please note that I feed the watermaker though our raw water system pump. The pump cyles on for a while, then off for a while due to the accumulator. Even when the engine is running. This says it's getting more than enough water. Otherwise the raw water pump would run continuously.

Pre filters. The string filter is the 5 micron one. The 20 is pleated. Flow is through the 20, the 5, then the watermaker. A 5 micron is necessary for silty water. Again, water flow is more than sufficient as proved by the pump cycling on and off for a while. The pump is "pushing" the water through the pre filters. Plus my flow meter and timed tests show output is always on the money. I will stick with my 5 micron, very THICK, string filters, thank you.

The 20 micron was replaced after 1 year. Perhaps I was not clear on that. It really was fine but I figured a year was enough. I tend to clean (yes gently wash) the pre filters sooner than needed. I went with the manufacturer's recommendation that as long as the filter is holding its shape and not collapsing, it's fine.

Timed test on water production showed no difference from new shortly before I sold that boat. Two years and the half year this go round, with absolutely no problems nor any drop in water production ever is all the proof I need that it's a good, workable system.

Rick

[Martinini]

I think if I spend that much on a watermaker it will be on something other then a Power Survivor, they seem to produce less water per dollar spent when compared to other good watermakers out there.

[speciald@ocens.]

My intake is on the port side just ahead of the keel. The water maker works well except when we are on a stb tack and making speed. In that situation we probably have some cavitation with air bubbles getting to the high pressure pump.

[Pete7]

Originally Posted by Martinini

I think if I spend that much on a watermaker it will be on something other then a Power Survivor, they seem to produce less water per dollar spent when compared to other good watermakers out there.

Yes but there purchase price is half of the Spectra, thats a big difference when fitting out a yacht for an extended cruise. $3500 this side of the pond for the 40 and $4200 for the 80E, struggling to find a UK dealer with a price for the Spectra 150 but from memory $6500. The hydrovane comes in at $5200. This includes VAT @17.5% (Euro tax) which with a bit of work ought to be refundable to anyone going off outside Europe.

The other way of looking at it is gallons for amps. However Rick makes a interesting point, about getting the size right.

Rick, how noisy was you 40E ? how does it compare to say running the engine if you were sat in the saloon with it running?

Thankfully it one thing we don't need to worry about at the moment in NW Europe, our back garden is starting to resemble the everglades after the lat couple of weeks

[Albro359]

My water intake is just aft of the keel about 1 foot from the center line, I don't have bubble problems underway....

My Schenker cost Eu5000...quite a bit more than the prices quoted here...but 35 litres per hour for 8 amps and not much more noise than a sewing machine...I think its great

[rickmorel]

Originally Posted by Pete7

The other way of looking at it is gallons for amps. However Rick makes a interesting point, about getting the size right.

Rick, how noisy was you 40E ? how does it compare to say running the engine if you were sat in the saloon with it running?

Noisy? The 40E was mounted in an open cabinet in the salon. It was annoying. Sounds like Creeee-craaaaaa creeee-craaaaa. Not as noisy decibel wise as the engine, but an agravating sound. I mounted the 80E in a cockpit locker and it's very muted and almost unnoticable sitting in the salon.

You also mentioned about Amp Hours per gallon. I started to, but didn't want to get too long-winded. If you look at all brands you'll find they all pretty much give you about the same Amp Hours per gallon. I had built a 6 GPH one, the smallest membrane I could find. When all was said and done, it would have taken almost 5 times the Amp Hours per gallon with a straight high pressure pump, so I sprung for the 80E.

The 40E met our needs, but I got a good deal on a new, damaged box 80E and it seemed worth it.

We use 4 to 6 gallons per day for 2 people, depending on a shower day or wash day. So the 80E runs 1 1/2 to 2 hours per day. I do make about 1/2 gal in a jug and feed from it prior to shut down.

I've heard people bad mouth the PUR (Katadyn), but never heard any reason why. They work and work well. They have the "pressure multiplier" or whatever you want to call it for reduced current draw and just go on and on and on. They were designed for the military. I have no interest in the company other than as a very satisfied customer.

I've heard so much that air in the system will damage the membrane, but Pur says it won't and just cuts down production. I ran the 40E a bunch with the "SNAP" of air before I came up with the raw water pump solution and it never damaged it, so I'll go with them. I've also heard that running in brackish or fresh water without reducing pressure will damage the membrane from heat. Pur says nothing about this and I made at least 300 gallons of water in brackish and fresh with no problem. There is no way to adjust the pressure. Well, there is, but I'm not going to plumb in a gauge and muck with it. I suspect the air and fresh thing is for the higher output ones, like maybe 20 GPH.

These things like to be run, and run daily. That's what we did and had no problems at all. I always ran product water in prior to shutdown. The only maintenance was cleaning pre filters and when it squeaked, putting a bit of silicon grease on the shaft.

In closing, I'd like to mention that, like all boat things, they are all very overpriced.

Rick

[Tellie]

Originally Posted by rickmorel

Tellie, I'm new to this particular list, but have a bit over 40 years of cruising.

However, I must respectfully disagree with your disagreement of my previous and current setups. Now, I'm talking sailboat and a "small" watermaker, as you put it. As an aside, anyone not aboard a 50-foot plus power boat has no business with a larger watermaker. Heck, when we had the PUR 40 we ran into several folks who wanted to trade their 8 or 12 or 20 GPH units for ours, with them ofering money in the deal. Too much water and too many Amp Hours were the reasons. They couldn't run them enough to operate properly and smoothly.

Please note that I feed the watermaker though our raw water system pump. The pump cyles on for a while, then off for a while due to the accumulator. Even when the engine is running. This says it's getting more than enough water. Otherwise the raw water pump would run continuously.

Pre filters. The string filter is the 5 micron one. The 20 is pleated. Flow is through the 20, the 5, then the watermaker. A 5 micron is necessary for silty water. Again, water flow is more than sufficient as proved by the pump cycling on and off for a while. The pump is "pushing" the water through the pre filters. Plus my flow meter and timed tests show output is always on the money. I will stick with my 5 micron, very THICK, string filters, thank you.

The 20 micron was replaced after 1 year. Perhaps I was not clear on that. It really was fine but I figured a year was enough. I tend to clean (yes gently wash) the pre filters sooner than needed. I went with the manufacturer's recommendation that as long as the filter is holding its shape and not collapsing, it's fine.

Timed test on water production showed no difference from new shortly before I sold that boat. Two years and the half year this go round, with absolutely no problems nor any drop in water production ever is all the proof I need that it's a good, workable system.

Rick

Hey Rick, disagree away, it's more fun that way.
I don't disparage your 40 years odd cruising because you're new here. Heck there's folks that have over a thousand posts here and arrived less than a year ago and never had a boat of their own. Don't make them experts either. But I got a few years under my belt as well. A few of em selling, repairing, and servicing so many watermakers I lost count. I bet we'd have fun talkin watermakers over a few beers.
I'm sure you've heard complaints from folks about their power hungry units. I hear it all the time Most people buy watermakers based on price first and end up finding out they made a big mistake. Glad you liked your 80E they are good units but anemic and power hungry when it comes to product per amp compared to a few others. I wish I could have a long talk with people before they buy a watermaker. It's a big expense to be sure. There is no such thing as a one size fits all watermaker. So while your 50 foot rule may work for you it really doesn't work for most. Plus guys are the worst people to make the watermaker decision. I can't tell you how many admirals drag their hubbys kicking and screaming in to buy a watermaker. Usually after their first cruise when he loaded up on blue jugs and recruited her help when the tanks got low. Just sayin.

[Tellie]

Originally Posted by Pete7

Yes but there purchase price is half of the Spectra, thats a big difference when fitting out a yacht for an extended cruise. $3500 this side of the pond for the 40 and $4200 for the 80E, struggling to find a UK dealer with a price for the Spectra 150 but from memory $6500. The hydrovane comes in at $5200. This includes VAT @17.5% (Euro tax) which with a bit of work ought to be refundable to anyone going off outside Europe.

The other way of looking at it is gallons for amps. However Rick makes a interesting point, about getting the size right.

Rick, how noisy was you 40E ? how does it compare to say running the engine if you were sat in the saloon with it running?

Thankfully it one thing we don't need to worry about at the moment in NW Europe, our back garden is starting to resemble the everglades after the lat couple of weeks

If you found the 80E at half the price of a Spectra you either found the deal of the month on the 80E or someone qouted you a very very high price on a Spectra. Though a Spectra will run you a bit more than a 80E you'll make a little more than twice the product with the same amps a 80E uses. Plus features that cost extra for a 80E come standard with a Spectra. Most who know me here know what I do, so I'm not trying to bend board rules here Mods. Spank me if I deserve it.

[senormechanico]

Originally Posted by Tellie

Though a Spectra will run you a bit more than a 80E you'll make a little more than twice the product with the same amps a 80E uses.

Agreed, and instead of Yeeeeee Yaaaawwww,

what you hear is

hummmmmmmm click hummmmmmm click.

A convert after a PowerSurvivor 35, then a PUR 80, now a Spectra 180.

[Albro359]

Rick,

I think you've got a few things wrong....

If you look at all brands you'll find they all pretty much give you about the same Amp Hours per gallon.

This statement is simply untrue...

The most power hungry for least output units are the old style straight high pressure pump / membrane systems

Next ...less power for more water...are the ones that feed back some of the waste brine into the intake

Best...are the Spectra / Schenker types with the fluid amplifier...they produce the most water for the least amps.

Just look at the specs of all three types and you will see it.

I think you'll find 35 l/hr (9 gals / hr) at 8 amps hard to beat...and quiet to boot !

[jackdale]

Originally Posted by duncan_ellison

Not exactly the OP's question, but has anyone considered the issue of cross contamination between the WM pick up and the drains on the boat, let's say the sink drain which may contain chemicals damaging to the membrane (chlorox, dishwashing liquid etc).

Did a delivery in which the head outlet was forward of the WM inlet. No using the head when the WM was running.

[Extemporaneous]

I had the same situation.
Started to use the sink discharge thru hull as an intake (port side of mid keel) and put a new thru hull on the starboard side of mid keel.
I now use the 2 in. (old sink discharge) for ALL water needs.
I know that everyone says have a dedicated water supply for the engine, but the math works with plenty of headroom to spare.

Regards,
Extemp.

Originally Posted by duncan_ellison

Not exactly the OP's question, but has anyone considered the issue of cross contamination between the WM pick up and the drains on the boat, let's say the sink drain which may contain chemicals damaging to the membrane (chlorox, dishwashing liquid etc).

The only obvious place for the WM pick up on my vessel is pretty close to the sink drain and I figure I'm going to need a small sign reminding the crew not to use the sink whwn the WM is running.

Anyone else considered this or do we expect the dilution to be so great that it wouldn't cause a problem.

Duncan