Anyone Tried Making your own Watermaker?

[s/v Beth]

Originally Posted by SV THIRD DAY

You can drive fresh water through an RO Membrane at a low pressure (45-65PSI) because fresh water (300 parts per million of salt) has a much lower osmotic pressure than does sea water (32,000 parts per million of salt). How much lower? Well you start driving sea water through the RO Membrane at about 600PSI, so roughly 10 times. There is a range of RO Membrane pressure operation, but 800PSI is the pressure that DOW Chemical uses as a standard to rate the flux rate of their membranes.

I've heard a lot of complaints from cruisers in anchorages over the years, but something I've never heard is a complaint about having too much water, too much rum, or too much Solar Power!

What about it Rich? If we could design and make something that would generate that much psi, would you help us out with the parts to complete the beta version? If it works well you could market it through your company.

I just see this as a hole in the market- there are hand held portable ones, then the motor driven ones. Remember our guy that sailed around the Americas? He suffered with his watermaker. There is one marketed that has a lever that you can attach to the motor drive if you are without electricity, but there is none that use a person in a running position (where we can put out the most energy) and produce water. Think of all the tiny yachts I see cruising that basically have a aversion to electricity....

[SaltyMonkey]

So, I need some clarification here. The document posted above describing the DIY water maker high pressure pump:

You will need a high-pressure pump of the triple-plunger positive-displacement type that can flow about 3 or 4 gallons per minute (GPM) and at least 1000 psi.

Yet…

but 800PSI is the pressure that DOW Chemical uses as a standard to rate the flux rate of their membranes.

What is the best rated PSI?

Also, the double membrane in the document = 40 GPH? T or F?

And finally a question:

Am I saving a significant amount of money making my own, or should I consider something like RO?

[a64pilot]

Sometimes the pride and intimate knowledge of the system gained on designing and building something yourself is worth more than money.
I say that as I doubt a home brew will save much if any money and is unlikely to be as trouble free or efficient as one that has gone through a series of development. Think if you built ten one after another, you learn from mistakes and each one get better than the last, but your only wanting to build one right?
Gotta think at least some of the watermaker companies started out like that, but once they got a good one designed and built, they go into selling. I have to think most are "built" from off the shelf commercially available parts, so they are assembled really.
I'm just guessing really, as I don't have a watermaker myself

[colemj]

Originally Posted by s/v Beth

What about it Rich? If we could design and make something that would generate that much psi, would you help us out with the parts to complete the beta version? If it works well you could market it through your company.

I just see this as a hole in the market- there are hand held portable ones, then the motor driven ones. Remember our guy that sailed around the Americas? He suffered with his watermaker. There is one marketed that has a lever that you can attach to the motor drive if you are without electricity, but there is none that use a person in a running position (where we can put out the most energy) and produce water. Think of all the tiny yachts I see cruising that basically have a aversion to electricity....

I don't think that hole in the market exists to an extent large enough to market to it. Personally, I don't think it exists at all - if anyone bought one, they would be looking for a real watermaker within a month.

Those handheld pump units produce almost no water. After a significant amount of pumping for hours, you will get a cup of water. I have talked to two people who have used them and they claim the amount of pumping is torture physically.

Let's say you could produce 8 cups of water in two hours on a stairmaster type system. I promise you, once out cruising, this will be your least favorite thing to do and you will dread it every waking moment. If you plan on having your wife and kids contribute, you will be without wife and kids within a week.

I really don't think you understand the power necessary to push a couple of gallons of water per minute through an RO membrane at 800psi, or the time necessary to push smaller amounts through.

Even if you hired a navy seal full time to operate it, you will be taking sponge baths and using a mister for teeth brushing. Anything left over will be going to rehydrate and unstink the navy seal.

Mark

[SaltyMonkey]

Originally Posted by colemj

Even if you hired a navy seal full time to operate it, you will be taking sponge baths and using a mister for teeth brushing. Anything left over will be going to rehydrate and unstink the navy seal.

Mark

I wouldn't get a Navy seal. I'd get a Green Beret -- you know, the SILENT warrior type.

[SaltyMonkey]

Anyone ever itemize the cost of the parts in those instructions? I question what it would cost in base to get a 20 GPH if you DIY.

[Tellie]

Originally Posted by s/v Beth

What about it Rich? If we could design and make something that would generate that much psi, would you help us out with the parts to complete the beta version? If it works well you could market it through your company.

I just see this as a hole in the market- there are hand held portable ones, then the motor driven ones. Remember our guy that sailed around the Americas? He suffered with his watermaker. There is one marketed that has a lever that you can attach to the motor drive if you are without electricity, but there is none that use a person in a running position (where we can put out the most energy) and produce water. Think of all the tiny yachts I see cruising that basically have a aversion to electricity....

There is the question. Is there a market for this? Outside of a very few people who like the idea of a human powered RO device, not much if any market at all. Certainly not enough to warrant the investment considering the "R" in ROI. If there was a market the major players would have already done it. The Katdyn 35 is a good example of a hand pumped watermaker that will produce what it claims but far more times than not it ends up buried under the bunk or a ditch bag never to be used only to find their way to E-Bay a few years later because effort to reward are highly unbalanced in favor of the effort. But can a stair master type device be used to produce the pressures needed to start the RO process? Sure but again, return on energy spent AND the time it would take to see any worthwhile results. How much time does the average crusier want to spend on a stair master watermaker? Even if you put two Katadyn 35s one under each step your production would be at best 0.05gpm. So you might make 3/4 of a gallon of water every fifteen minutes, don't forget the gallon of water you'll need to flush the system if you want it to last. Next time your at a gym see how long on average a person stays on the stair master. You would probably see this device as something to unload at the next port. Producing the pressures needed to start the RO process is actually the easy part. Producing the proper pressures and flow is another thing all together. If you're not going to turn a standard plunger pump that can produce pressure and flow at the rpms required, you will have to come up with a new idea and design to create the pressure and flow needed. If you can do that then you might have something. But even if you did come up with that the ROI comes back into play and you'd be a lousy business and quickly out of business if you only built these for those "Tiny Yachts" who still most likely wouldn't spend the money on one and those that can easily afford a watermaker would not be interested in it. I don't mean to sound like I'm poking holes or dismissing effort and ingenuity, far from it. If you can conquer the known limitations then by all means do so and please let me know first, I could make us all very wealthy.

[colemj]

Originally Posted by SaltyMonkey

So, I need some clarification here. The document posted above describing the DIY water maker high pressure pump:



Yet…



What is the best rated PSI?

Also, the double membrane in the document = 40 GPH? T or F?

And finally a question:

Am I saving a significant amount of money making my own, or should I consider something like RO?

The pump must be rated above that of the membrane or it will be operating on the edge and at constant risk of failure. The actual pressure a RO membrane operates at is not a set pressure, although most people operate it in such a way. The pressure should be adjusted so that the flow remains constant. This will change between 750-900psi depending on environmental conditions (temperature, salinity). In practice, it is easiest to just take it to a single pressure all the time.

Adding additional membranes increases production, assuming you have the pump water flow capacity to support it.

Yes, you can save money by making your own. Even more if you hunt ebay, etc for bargains - but this could take a long time. It is a personal opinion whether that savings is significant. I certainly have all the knowledge and experience with watermakers necessary to easily build my own, but I bought one instead. You will be doing enough work modifying the mounting area, installing plumbing and putting the system together. Receiving all of the parts (and extras) in one package for ~1/4 more money made up for the time and effort to me of having to specify and hunt down individual components and plumbing and shipping them separately.

Mark

[SaltyMonkey]

@colemj Yes it may be one of those tasks / items on the list that should be outsourced -- considering your own labour rate in the overall picture of getting the yacht ready.

[Cheechako]

Yes, I've made my own a couple times. A basic manually controlled watermaker is easy to make. It's just a pump, membrane/vessel and a needle valve/pressure relief valve. You close the needle until the proper pressure is reached forcing seawater thru the membrane and it makes water. Somtimes pump is needed to prime the hi pressure pump. A filter before the pump is good too.
I made one out of an older AC unit. Took the Cat pump off, bought a 12v electric clutch for the pump.

[SV THIRD DAY]

Originally Posted by s/v Beth

What about it Rich? If we could design and make something that would generate that much psi, would you help us out with the parts to complete the beta version? If it works well you could market it through your company.

I just see this as a hole in the market- there are hand held portable ones, then the motor driven ones. Remember our guy that sailed around the Americas? He suffered with his watermaker. There is one marketed that has a lever that you can attach to the motor drive if you are without electricity, but there is none that use a person in a running position (where we can put out the most energy) and produce water. Think of all the tiny yachts I see cruising that basically have a aversion to electricity....

Having the technical advantage of know the details of RO...it just won't work guys. You can't generate enough FLOW rate at the needed pressure to get any reasonable amount of fresh water. The power Survivor 35 tried it...what does 1.5GPH get you? Sure life raft water (but your arm would fall off long before you died of thirst)...but not enough for showers or comfortable cruising.

Originally Posted by a64pilot

I'm just guessing really, as I don't have a watermaker myself

Thanks to A64pilot who as least admitted he didn’t have a water maker and is guessing? Most internet advice givers don’t tell you they have never actually done what they are giving you advice to do! A large amount of advice I’ve seen on the internet about how to make a water maker for $1000 is just totally wrong and will leave you with an expensive lesson in the powers of high pressure sea water corrosion and RO Membrane flow properties.


Real quick before I have to travel to …uggg….Bakersfield to spend Easter Weekend with my non-boater family.


1. There is a pressure range for RO Membrane operation (650 to 950 PSI). Most people like to use 800PSI as the standard set-point as a way to try and balance membrane production with membrane life/health. See as pressure goes up, you drive more fresh water through the RO Membrane…BUT you also are working the membrane harder and can promote scale build up if you don’t have enough brine discharge. It’s all a balancing act in production vs cost of membrane replacement. The 800psi number sticks because it is what DOW recommends for the operating pressure of a continuous duty 24/7 desalination plant which is what they are targeting with their membrane specs with a 7 year life.





2. Three things control RO Water production: Flow Rate, Membrane surface area, and Pressure
(or temp and salinity also does…but lets assume those are a constant)
You can increase the membrane surface area BUT only to a limit or your brine discharge falls off enough that you will have scaling and fouling of the membrane. So you can’t just stack up membrane after membrane…all that concentrated salt needs flow rate to keep it soluble and from precipitating out on your membrane. At the end of the day it is a balance between membrane surface area and flow rate…more flow rate is always good for the membrane…but that flow rate costs energy…power to create. This is where SO MANY DIY guys go wrong and end up with dead membranes from not balancing the flow and surface area. Of course they will never make a post detailing how they screwed up…because they may not ever know….but I get their calls all the time asking why their membranes are only lasing 6 months to a year when their friends are lasing years and ours are fully warrantied for 3yrs.


3. It depends on what your definition of “significant” is. As Tellie said, counting your labor you won’t save any real money. Heck, you are probably better working a few days of overtime and making money to just buy one, but you can’t discount the “cool factor” of making your own. I get and understand that. I know what my raw parts cost me, I know my margin, and I know what the raw parts will cost you. You will be buying one off orders not a pallet of 50 Hp pumps like we do then you have all those individual shipping costs to add in, the parts that didn’t work or fit, etc. no warranty, no phone call with someone to help, these are costs also that get overlooked. The 50GPH water maker I built ended up like most home brew units, saving me a little but not the dream of 50% off everyone loves to talk about on the internet, but I did have fun doing it. And here is the big one. It was easier to tell my wife I was going to spend that much money one chunk at a time (while bragging to her about all the money I was saving…true or not) than to get her permission to buy an off the shelf water maker all in one chunk! That is the issue I think. All the smaller costs of parts make things seem cheaper than one big chunk at once especially if you never add them all up and only remember the big costs like the Hp Pump, PV, etc.

[SV Windrush II]

Originally Posted by SV THIRD DAY

Having the technical advantage of know the details of RO...it just won't work guys. You can't generate enough FLOW rate at the needed pressure to get any reasonable amount of fresh water. The power Survivor 35 tried it...what does 1.5GPH get you? Sure life raft water (but your arm would fall off long before you died of thirst)...but not enough for showers or comfortable cruising.


Thanks to A64pilot who as least admitted he didn’t have a water maker and is guessing? Most internet advice givers don’t tell you they have never actually done what they are giving you advice to do! A large amount of advice I’ve seen on the internet about how to make a water maker for $1000 is just totally wrong and will leave you with an expensive lesson in the powers of high pressure sea water corrosion and RO Membrane flow properties.


Real quick before I have to travel to …uggg….Bakersfield to spend Easter Weekend with my non-boater family.


1. There is a pressure range for RO Membrane operation (650 to 950 PSI). Most people like to use 800PSI as the standard set-point as a way to try and balance membrane production with membrane life/health. See as pressure goes up, you drive more fresh water through the RO Membrane…BUT you also are working the membrane harder and can promote scale build up if you don’t have enough brine discharge. It’s all a balancing act in production vs cost of membrane replacement. The 800psi number sticks because it is what DOW recommends for the operating pressure of a continuous duty 24/7 desalination plant which is what they are targeting with their membrane specs with a 7 year life.





2. Three things control RO Water production: Flow Rate, Membrane surface area, and Pressure
(or temp and salinity also does…but lets assume those are a constant)
You can increase the membrane surface area BUT only to a limit or your brine discharge falls off enough that you will have scaling and fouling of the membrane. So you can’t just stack up membrane after membrane…all that concentrated salt needs flow rate to keep it soluble and from precipitating out on your membrane. At the end of the day it is a balance between membrane surface area and flow rate…more flow rate is always good for the membrane…but that flow rate costs energy…power to create. This is where SO MANY DIY guys go wrong and end up with dead membranes from not balancing the flow and surface area. Of course they will never make a post detailing how they screwed up…because they may not ever know….but I get their calls all the time asking why their membranes are only lasing 6 months to a year when their friends are lasing years and ours are fully warrantied for 3yrs.


3. It depends on what your definition of “significant” is. As Tellie said, counting your labor you won’t save any real money. Heck, you are probably better working a few days of overtime and making money to just buy one, but you can’t discount the “cool factor” of making your own. I get and understand that. I know what my raw parts cost me, I know my margin, and I know what the raw parts will cost you. You will be buying one off orders not a pallet of 50 Hp pumps like we do then you have all those individual shipping costs to add in, the parts that didn’t work or fit, etc. no warranty, no phone call with someone to help, these are costs also that get overlooked. The 50GPH water maker I built ended up like most home brew units, saving me a little but not the dream of 50% off everyone loves to talk about on the internet, but I did have fun doing it. And here is the big one. It was easier to tell my wife I was going to spend that much money one chunk at a time (while bragging to her about all the money I was saving…true or not) than to get her permission to buy an off the shelf water maker all in one chunk! That is the issue I think. All the smaller costs of parts make things seem cheaper than one big chunk at once especially if you never add them all up and only remember the big costs like the Hp Pump, PV, etc.

Thanks for all the good input Rich,

After checking out your website, models and prices. I am now struggling to legitimize building my own, considering I can purchase a RO unit for about $4k, I just cannot afford other models that I have seen for $6-10k.
I appreciate you keeping your prices down so that it makes it more reasonable to purchase.
The only thing I was wanting is a DC powered unit so I can run it off my batteries instead of a Inverter or my Diesel engine.

I plan on having a lot of solar, wind and water power generation on board that I believe can keep up with the batteries on a good day while my watermaker is running to fill up my 200 gal fresh water tanks.

Can you change out the AC motor to a CD motor? I see that Lesson makes a 12v 1hp DC motor

Buy 12 Volt Electric Motors | Replacement 12v Electric DC Motors

Thanks!

[hellosailor]

Newt, if you build a mechanical system that's a one-trick pony and it requires a certain amount of work from the "engine" person, which may not be reliable or consistent.

I'd be inclined towards an electrically operated system, since solar panels and other sources can replace your leg power when you get the flu, or twist an ankle, or the temperature is just too hot and humid to be pumping.

Just a thought.

[a64pilot]

Or drive the HP pump form the Diesel, using an AC clutch to engage/disengage if you building your own, especially if you ever use the alt to charge batteries, help add load to the Diesel

[Cheechako]

Originally Posted by leightonyachts

Thanks for all the good input Rich,

After checking out your website, models and prices. I am now struggling to legitimize building my own, considering I can purchase a RO unit for about $4k, I just cannot afford other models that I have seen for $6-10k.
I appreciate you keeping your prices down so that it makes it more reasonable to purchase.
............
Can you change out the AC motor to a CD motor? I see that Lesson makes a 12v 1hp DC motor

Buy 12 Volt Electric Motors | Replacement 12v Electric DC Motors

Thanks!

remember, that 12v motor will be drawing about 65 amps!!! My watermakers were engine drive, I could filla 100 gal tank in 4 hours of motoring, or if charging batteries for an hour make 25 gals....
For kits also check out these folks, they sell good stuff: http://aquamarineinc.net/beltdrive.html