For those thinking of fitting a watermaker

[dgadee]

That's quite a small pump. Mine is rated at twice the flowrate.
What size motor do you use? Do you know what power the motor runs at?

1hp motor. It is a motor to drive an agricultural fan and was the only low power start motor I could find with the correct face. It has no cooling fan so I use a computer fan to cool it. Not measured actual power consumption.

The idea of the design with that pump was that it was the maximum a Honda EU20i would run (ie start).

We are only 2 and run it an hour every two days. More if we are motoring anyway. It is noisy but gives us flexibility and freedom from seeking taps. The engine is always on, too, to put power back into the batteries during water production. We have around 300L of storage.

Hadn't used the Honda for 2 years since I put in the 2kww pure sine inverter. But the house batteries are failing so it has been called into action again. We go home in a few days so new batteries for next spring.

Around 1.5L per minute. 90L per hour or so? More when I go 3 phase but not really needing much more.

 

[geem]

1hp motor. It is a motor to drive an agricultural fan and was the only low power start motor I could find with the correct face. It has no cooling fan so I use a computer fan to cool it. Not measured actual power consumption.

The idea of the design with that pump was that it was the maximum a Honda EU20i would run (ie start).

We are only 2 and run it an hour every two days. More if we are motoring anyway. It is noisy but gives us flexibility and freedom from seeking taps. The engine is always on, too, to put power back into the batteries during water production. We have around 300L of storage.

Hadn't used the Honda for 2 years since I put in the 2kww pure sine inverter. But the house batteries are failing so it has been called into action again. We go home in a few days so new batteries for next spring.

Around 1.5L per minute. 90L per hour or so? More when I go 3 phase but not really needing much more.

Are you running a pair of 40" membranes? If so, assuming warm water, you might be able to push the production rate up some more with a faster motor speed. The limit of production seems to be about 75litres per hour per 40" membrane. It hold true for one or two in series. By the time you get 3 in series, you only get 50l/hr out of the third membrane in the run.

 

[geem]

not quite sure I follow geem.
My inverter is setup so that it starts at 1Hz and reaches 50Hz after 60sec (or 120 don't remember what I've programmed there!). Needle is not touched in the process obvs.
So monitoring what's happening, I can see on the boost gauge on the watermaker that pressure builts up nice and slow within this time from 0 to the full 800psi which I believe is what matters.
Don't really get the inrush current thing, care to explain please?

V.

In rush current occurs in star Delta and DOL motors. The extra power needed to accelerate the motor from stationary to full running speed uses a lot more power than just turning the motor at its design speed. This is seen as a current spike as the motor starts. With your soft start, you won't see this spike. Frequency inverters are great for this.
Do you have an automatic pressure control valve?
Most basic AC watermakers use a manual needle valve. Super simple. Start at zero pressure with the motor running and just turn the valve slowly until you reach 800psi. Very littl3 to go wrong

 

[vas]

Yes, freq inverter, v.clever piece of kit.
no, old school strangling manual valve, works fine. Main reason for doing all this conversion was to avoid having to go down to the lazarette everytime I was turning on the watermaker to turn up the pressure and back to release it before turning off.

 

[geem]

Yes, freq inverter, v.clever piece of kit.
no, old school strangling manual valve, works fine. Main reason for doing all this conversion was to avoid having to go down to the lazarette everytime I was turning on the watermaker to turn up the pressure and back to release it before turning off.

Ah, mine is conveniently located on the bulkhead in the engine room. I just walk-in off the saloon

 

[Grith]

Size, weight, fitment location, power and cost all contributed to my ultimate purchase. We do long periods coastal cruising in a trailerable yacht and generally don’t need a watermaker with 200litres of water storage and not going far offshore.
A proposed 3/4 month cruise next year to a very remote location without resupply availability relying on uncertain and at times difficult or dangerous to reach wild water sources had me scratching around for the best solution.
The Aus $6,000 to $10,000 anvailable options were difficult to justify on both price and longer term likely use as well as weight and fitment constraints on our already tightly packed small yacht.
I purchased a secondhand Katadyn survivor 40e which I have now made it into a cased portable unit and I am just finalising prior to testing as my possible solution.
It just now needs two right angle pipe fittings into and out of the prefilter which has slotted mounts to allow its easy removal for filter change outs and an external Anderson pug with switch to complete the unit.
With low power draw at around 12v 4 amps my solar system will easily cope with the proposed 2 hours a day usage to produce around 10 litres which is slightly higher than our long term tested 8-9 litres average use for the two of us.
The pelican case knock off was cheap at A$100 new and the Katadyne unit with a new unfitted membrane, seal kit and lots of other spares and replacement filters and pickling solution was $2,000 for a 370 hour unit deinstalled from an older cruising yacht about to be sold where the owners felt it wouldn’t add extra value to that sale but had been in regular use.
It will store in my stern generator box as that manufacturer fitted location is now no longer needed due to my new large solar array. The operational location is immediately behind this on the swim platform secured by the case handle to a Bimini support and the inlet and waste water tubes directly over the stern.
I had to cut a hole on the base for the motor to slightly protrude to fit it all in the smallest possible case but this also provides the space for the inlet and outlet water tubes whilst the motor end still doesn’t touch the ground with the case upright due to stands on the case to protect the hinge.
It’s been and interesting thought process and a solution I hope to possibly a once off problem.
If it works as planned the unit should then be either very saleable and the end of next years trip or alternatively we may keep it but move it between our various water and land adventure platforms when spending extended periods away from fresh water sources.
Last photo shows the swim platform accessed generator locker which it snugly fits inside on one side still leaving room for our small Honda eu10 and a fuel container or more likely just general storage as our last 2 months trip never required this backup power source despite cooking by induction, compressor fridge and separate freezer and our 240v hot water service used occasionally for showers.

 

[dgadee]

Are you running a pair of 40" membranes? If so, assuming warm water, you might be able to push the production rate up some more with a faster motor speed. The limit of production seems to be about 75litres per hour per 40" membrane. It hold true for one or two in series. By the time you get 3 in series, you only get 50l/hr out of the third membrane in the run.

Yes, 2 at 40". Fsster motor would require more power input? We are not in a large boat (11m) and don't want a diesel generator.

 

[geem]

Yes, 2 at 40". Fsster motor would require more power input? We are not in a large boat (11m) and don't want a diesel generator.

Yes, it's hard on a monohull to fit a lot of solar. We do know boats with 1000w on a solar arch but in my opinion they look terrible. Its a hell of a lots of weight high up and when sailing, they are often pointing the wrong way. In addition, their performance is not always great since they sit totally flat at anchor. We manage with 360w of solar each side of the guardwires (that tilt) plus an additional 200w of roving solar whilst at anchor. For the rainy days, we do have a diesel genset. We can put in up to 115Ah @24v if we needed to. We don't. Instead of the weather is cloudy we may use the genset to make water occasionally and turn on about 45Ah of charger (@24v). We don't do it often. Sometimes may be once a month. Sometimes once a week.

 

[Grith]

Our trailer sailer is only 8.5 metres long and 2.5m at its very widest point. Photo here shows her carrying 720w of solar panels comprising 3x180w mounted fairly unobtrusively directly on top of our Bimini and a further identical tiltable panel on the rear targa bar supporting the rear of the Bimini and a variety of other functions
With a further 160w hard port starboard tiltable panel over the cabin roof and now just purchased a further 440w of roving fold up flexible panels which mount on the upturned dingy, secondary at anchor cockpit covering fold up Bimini and on the dodger and mainsail bag we have managed the well over 1000w of solar panels on a both quite small and trailerable yacht.
The hard panels have just survived over 5000 kilometres erected whilst the yacht was towed on its trailer for southern Australia to the Barrier Reef and return.
Yes it doesn’t have beautiful classic lines but it doesn’t look like an ill conceived mess either.
The panels also fold to allow the yacht to be derigged for trailering whilst still on water which took quite some puzzle like figuring out of angles and support bar adjustability.
We have added the extra flexible panels as our just completed over 2 months cruise saw is just squeak by at the beginning having started our cruise in two weeks of heavy overcast and rain and I had deliberately left our suitcase generator behind. We also were driven back into civilisation to refill our water ( and also alcohol ) the second being a miscalculation of consumption and the other a pre water maker trial of how far we can could stretch our 200 litres of stored water.
Not far enough for next years planned 3/4 months without the ability to resupply hence my almost completed Katadyn survivor in a box portable water maker in progress now.




This was taken a few days ago and it has had further modifications since then and is about to be tested for performance , noise and and general usability.
The case is now padded top and bottom and sits on special noise and vibration reducing feet pinched from a dead Honda suitcase generator.