watermakers from Jetwashers

Brent Swain said:
Many cruise these sites looking for info, and the recently posted info was not in the previous posts. The rest is just as relevant today for those seeking info as it was 5 years ago.
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I don't think you read my objection carefully enough - what I proposed would work very effectively, without any of the disadvantages of resurrecting a dead thread. The Time Inc IT people might also find a way of highlighting the age of dead threads.
 
Adding to an existing thread works fine. If it aint broke don't fix it.
Then there is the govt version
If it aint broke , fix it until it is broke.
I think you are just trying to stir the pot, and provoke.

pvb said:
I don't think you read my objection carefully enough - what I proposed would work very effectively, without any of the disadvantages of resurrecting a dead thread. The Time Inc IT people might also find a way of highlighting the age of dead threads.
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Wolf has used the one I use, since the 90s including a trip from BC to New Zealand and back with no problems.
How much does your cat pump cost?
Yes, what you propose is simple . The only think simpler is a belt drive off the main engine.
220 volt , 1.5 kv electric motors are anything but inexpensive, compared to a belt and pulley .
Nor is the ability to put out that kind of electrical power.


geem said:
Brent Swain said:
If it vibrates, you are getting air in. Hard on pumps.
A friend, who made them for a living, said pressure washer pumps are far more solidly built than those made for water makers .He said Italian made ones were the best, US made ones were the worst.
He said 80% of water maker problems were with electric drive.

This does not fit with my experience. Cat make watermaker pumps and pressure washer pumps. They are the same thing. The only item that changes is the cylinder head. They are made in three basic materials. Brass, s/s and nickel bronze. S/s and bronze are chosen for watermakers for their resistance to seawater corrosion. All other parts on the piston pump are the same.
In my experience 12v watermakers are the least reliable. Due to their small 12v motors they employ complex energy recovery sustems and automatic controls. The simplest reliable high output watermaker would be a cat pump and a direct coupled 220v 1.5kw motor. Little to go wrong. No automatic controls just a needle valve to set the pressure and a derverter valve to select water tank or test pipe. Apart from the drive motor (available off the shelf worldwide) there are no other electrical parts.
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It's surprising how low below the waterline you have to put your intake, to avoid sucking air in, when underway ,especially in rough water. Put it as low as possible. Standard pre-filtres are often made for houses, and the air vent on top is for pressure, not vacuum. Thus you have to seal it with lots of sikaflex, to stop it from sucking air in.
 
Brent Swain said:
Wolf has used the one I use, since the 90s including a trip from BC to New Zealand and back with no problems.
How much does your cat pump cost?
Yes, what you propose is simple . The only think simpler is a belt drive off the main engine.
220 volt , 1.5 kv electric motors are anything but inexpensive, compared to a belt and pulley .
Nor is the ability to put out that kind of electrical power.



A belt drive off the engine is not always easy. Space in some engine installations prohibits this.
A 220v 1.5kw motor costs between £115-200. Since we have a diesel generator operating this motor is easy for us.
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geem said:
Brent Swain said:
Wolf has used the one I use, since the 90s including a trip from BC to New Zealand and back with no problems.
How much does your cat pump cost?
Yes, what you propose is simple . The only think simpler is a belt drive off the main engine.
220 volt , 1.5 kv electric motors are anything but inexpensive, compared to a belt and pulley .
Nor is the ability to put out that kind of electrical power.




A belt drive off the engine is not always easy. Space in some engine installations prohibits this.
A 220v 1.5kw motor costs between £115-200. Since we have a diesel generator operating this motor is easy for us.
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Yes, I didn't have room in my engine compartment, so I made a removable panel in the side, thru which the belt runs. It is also a good spot for my alternator welder( which my book shows you how to build).
A belt eliminates the need for a big, heavy , expensive ,noisy diesel generator on board.
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Brent Swain said:
geem said:
Yes, I didn't have room in my engine compartment, so I made a removable panel in the side, thru which the belt runs. It is also a good spot for my alternator welder( which my book shows you how to build).
A belt eliminates the need for a big, heavy , expensive ,noisy diesel generator on board.
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If you have already made the decision to have a diesel generator for other reasons such as enough hot water for a couple of showers from 12mins of generator use via an immersion heater, fast battery charging from large battery charge via generator, running a spinner for washing clothes or a washing machine, 220v to operate large power tools when doing a bit of maintenance then running a 220 v motor is a no brainier. Why you think a diesel generator is more noisy than a yacht engine with a hole in the compartment for a belt, I have no idea. Our generator lives in an acoustic box inside an acoustic lined engine room. Effectively double insulated from noise. A pleasure to operate for making water compared to running the main engine at elevated revs to give the correct watermaker pump speed
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geem said:
Brent Swain said:
If you have already made the decision to have a diesel generator for other reasons such as enough hot water for a couple of showers from 12mins of generator use via an immersion heater, fast battery charging from large battery charge via generator, running a spinner for washing clothes or a washing machine, 220v to operate large power tools when doing a bit of maintenance then running a 220 v motor is a no brainier. Why you think a diesel generator is more noisy than a yacht engine with a hole in the compartment for a belt, I have no idea. Our generator lives in an acoustic box inside an acoustic lined engine room. Effectively double insulated from noise. A pleasure to operate for making water compared to running the main engine at elevated revs to give the correct watermaker pump speed
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Yes, if you have already installed a diesel generator, you may as well get the max use out of it. If you haven't ,then you have to consider the advantages of keeping things much simpler.
Given your main engine gives you far more horsepower than you need to power a 3 gpm pump, you can put the appropriate pulleys on, to let you run your watemaker with the engine barely idling.
I met a guy named Dave Malseed in the Marquesas in the 70s ,who was writing a book on marine refrigeration. He said electric meant burning fuel which was 60% efficient, to charge a battery which was 25% efficient, to run a motor which was 60% efficient, to run your compressor. A direct belt off your engine was far more efficient ( and much easier to deal with, in the event of a failure in remote areas.)
20 minutes a couple of times week would give me all the water I need.
Some cruisers have no interest in all the complicated gear you mention.
Keep it simple!
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pvb said:
I don't think you read my objection carefully enough - what I proposed would work very effectively, without any of the disadvantages of resurrecting a dead thread. The Time Inc IT people might also find a way of highlighting the age of dead threads.
Click to expand...

What was in the dead thread is just as relevant today, for someone seeking such info. I don't see the point in breaking up any relevant info into a bunch of separate threads, forcing anyone seeking info on the subject, to wade thru many of them, with the thus increased chance of missing something critical to their situation .
Keep it simple , altho there is a recent trend in " Yottieness" to believe that if you can come up with a more complicated and expensive way of accomplishing the same thing , then you absolutely "MUST" be doing a better job of it.
The marine industry has a huge financial stake in promoting that way of thinking.
It has sunk a lot of cruising dreams.
 
Brent Swain said:
geem said:
Yes, if you have already installed a diesel generator, you may as well get the max use out of it. If you haven't ,then you have to consider the advantages of keeping things much simpler.
Given your main engine gives you far more horsepower than you need to power a 3 gpm pump, you can put the appropriate pulleys on, to let you run your watemaker with the engine barely idling.
I met a guy named Dave Malseed in the Marquesas in the 70s ,who was writing a book on marine refrigeration. He said electric meant burning fuel which was 60% efficient, to charge a battery which was 25% efficient, to run a motor which was 60% efficient, to run your compressor. A direct belt off your engine was far more efficient ( and much easier to deal with, in the event of a failure in remote areas.)
20 minutes a couple of times week would give me all the water I need.
Some cruisers have no interest in all the complicated gear you mention.
Keep it simple!
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I don't disagree at all about keeping it simple. The dilemma with belt driven optimised for engine idle is you can't use the watermaker on the move. We often make water with the main engine running by powering the watermaker motor via the inverter. We have a 3kw low frequency inverter that easily powers the 1.5kw motor. The alternator won't keep up with the draw through the inverter but we only need to run it for 1/2 an hour to make 65 litres. This is our back up system.
As far as efficiency is concerned, if we use the generator to make water and don't take advantage of the generator being on to make hot water or charge batteries then our half loaded generator uses a litre per hour. Diesel costs us £0.55/litre so every litre of water we make costs us 0.42p. We make 1200 litres per month so in fuel costs is £5.
I recently changed the Perkins twin cyclinder generator Diesel engine for another I bought off EBay. My first engine died after 17 years after it dropped a valve. You can buy these engine very cheaply new. The generator alternator is brushless with a single bearing at one end. Very little to go wrong. Not as simple as not having one though!
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geem said:
Brent Swain said:
I don't disagree at all about keeping it simple. The dilemma with belt driven optimised for engine idle is you can't use the watermaker on the move. We often make water with the main engine running by powering the watermaker motor via the inverter. We have a 3kw low frequency inverter that easily powers the 1.5kw motor. The alternator won't keep up with the draw through the inverter but we only need to run it for 1/2 an hour to make 65 litres. This is our back up system.
As far as efficiency is concerned, if we use the generator to make water and don't take advantage of the generator being on to make hot water or charge batteries then our half loaded generator uses a litre per hour. Diesel costs us £0.55/litre so every litre of water we make costs us 0.42p. We make 1200 litres per month so in fuel costs is £5.
I recently changed the Perkins twin cyclinder generator Diesel engine for another I bought off EBay. My first engine died after 17 years after it dropped a valve. You can buy these engine very cheaply new. The generator alternator is brushless with a single bearing at one end. Very little to go wrong. Not as simple as not having one though!
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I have used mine motor sailing with the engine idling.One could have two pulleys on the engine , one the right size for idling, and one for full speed motoring. Put the belt on the one which matches what you plan to do for the day.
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Brent Swain said:
geem said:
I have used mine motor sailing with the engine idling.One could have two pulleys on the engine , one the right size for idling, and one for full speed motoring. Put the belt on the one which matches what you plan to do for the day.
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Keep it simple eh? Hmm, dual pulleys, clutch? cut holes in bulkheads?
S
PS the pump is still here if anyone fancies experimenting.
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skipper_stu said:
Brent Swain said:
Keep it simple eh? Hmm, dual pulleys, clutch? cut holes in bulkheads?
S
PS the pump is still here if anyone fancies experimenting.
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So what is your solution ,which is simpler than a couple of pulleys and a belt? Surely, you are not claiming that an electric drive, with a generator, batteries and an electric motor is simpler, in the event of a break down in a remote area!
Don't keep us in suspenders ,let us know.
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Brent Swain said:
skipper_stu said:
So what is your solution ,which is simpler than a couple of pulleys and a belt? Surely, you are not claiming that an electric drive, with a generator, batteries and an electric motor is simpler, in the event of a break down in a remote area!
Don't keep us in suspenders ,let us know.
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You either rely on a single solution that is simple like yours but you have no redundancy. If your engine fails you lose the abilty to make water and a lot of other things such as charging or hot water.
If you go engine and generator route like we do and many others, you have inherant redundancy. We can make water with either. We dont carry a spare motor but we do carry a spare pump. There are merits of both approaches but I suspect boat design and size have a lot to do with it. If you dont have room for a generator you are likley to go engine driven or 12v motor. My preference would be engine driven given this scenario
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