Anchoring Amps/Day

[Zonker]

Very efficient. Our model was a bastardized "Newport". (I threw away all the automatic solenoid valves/salinity controls/flush valves etc and went strictly manual).

It had 2 feed pumps. Using 1 pump it would draw about 8 amps / 6-7 GPH. (So 8 a.hr for 23-26 l/hr). When the engine was running (excess power) we would sometimes run both pumps and make nearly double.

So yeah 8 amps when the solar panels are putting out 20+ was nothing.

 

[accnick]

Yah

two weeks cruise is about max for a small craft

at two weeks you run out of food , water, fuel , batteries are soft and your crew are all burnt up and begin to stink

What constitutes a "small craft" to you?

 

[slug zitski]

What constitutes a "small craft" to you?

the off the shelf 40 footer that’s nice to sail

 

[Veeger]

Zonker's post (and others) pretty much confirms what I've always used as a rule of thumb for a 12v watermaker. 1 amp hour per gallon of water made. Some may do a bit better, some maybe worse but it's pretty good down and dirty estimate when planning your electrical consumption needs.

 

[Zonker]

This only works if you have a pressure recovery type watermaker like a Spectra or Schenker.

A watermaker that just uses a big DC high pressure pump is about 1/2 that.

 

[accnick]

This only works if you have a pressure recovery type watermaker like a Spectra or Schenker.

A watermaker that just uses a big DC high pressure pump is about 1/2 that.

To clarify, a watermaker with a conventional DC high pressure pump typically consumes about twice the electricity per gallon of water produced compared to a watermaker with an energy recovery pump.

I looked at the Schenker energy recovery models at the Fort Lauderdale show last month. It's an interesting option, but I note that their average claimed TDS is 300, while our Little Wonder was consistently around 200.

We had a Village Marine Little Wonder 12v watermaker on our last boat. That one had a conventional DC high pressure pump. I only ran it when the engine was running to charge batteries, as the higher voltage made the motor run a bit more efficiently. To produce about 6 gph, it consumed right at 12 amps when running. I had good electrical metering to monitor this.

The engine-driven refrigeration compressor was also bringing down holding cold plates in the freezer at the same time, so it was a reasonably efficient use of the 40 hp main engine, when you also add in the battery charging.

That was a great little watermaker. We replaced the membrane once in six years, and the HP pump had developed a tiny weeping leak by the time we got back to the US. We produced probably 80 percent of our own water over six years and 40,000 miles. Only when we were someplace with trusted water quality would I put shore water in the tanks. I would also never make water in a marina full of cruising boats with people aboard in any case.

Because we rarely pickled the membrane, we sometimes made more water than we could use, and we would give the excess to other boats without watermaking capabilities.

We did not carry water jugs on the boat to tote water. In fairness, we had 180 gallons of water tankage for two people. Once I put in a saltwater washdown pump, and stopped using fresh water to wash the anchor chain, our water consumption was no more than 5 gal/day for two people, and my wife is not a serious water conserver. We did not have a saltwater pump in the galley.

Access to potable water was not a cruising constraint.

Right now, fresh water is our primary cruising range/time limiter. A watermaker would solve that, but unfortunately, it's not at the top of to-do the list, so I carry extra jerry jugs of water.

 

[Zonker]

It's an interesting option, but I note that their average claimed TDS is 300, while our Little Wonder was consistently around 200.

Our Spectra ran around 225 with a new membrane, and gradually rose to around 300. Couldn't notice a taste difference. We did have to put in a new membrane when it was pickled for 2.5 years and didn't survive. The TDS was ~550 and that tasted nasty.

Village Marine used to use their own proprietary membranes that were a non standard size (maybe they still do). Anyway they were ~$600 to replace versus our $150 Dow standard 2.5x40" ones

 

[accnick]

Our Spectra ran around 225 with a new membrane, and gradually rose to around 300. Couldn't notice a taste difference. We did have to put in a new membrane when it was pickled for 2.5 years and didn't survive. The TDS was ~550 and that tasted nasty.

Village Marine used to use their own proprietary membranes that were a non standard size (maybe they still do). Anyway they were ~$600 to replace versus our $150 Dow standard 2.5x40" ones

The VM ones were about half the length and capacity of the standard membrane. They were about $200 when we were out cruising.

Schenker uses those same shorter membranes in most of its smaller watermakers. I didn't check what they were selling the membranes for. Not sure who makes those membranes, or how the cost compares with a "standard" one.

 

[Max Rockatansky]

I have a 12V Katadyn 160e. Draws 20 amps making 6.5gal/hr. Membrane is 2.5x21” Dow filmtec.

I have bought (used) and am rebuilding a Sun Pure watermaker. It’s rather agricultural, but everything is off the shelf. They are claiming 8-12 gal/hr, and I’ve calculated it should draw 30amps, they are claiming 24. we’ll see