Running a Watermaker Inshore?

[djousset]

We have used a water maker (Rainman) in Biscayne Bay with no problem. Flush with fresh water when finished

[chuckr]

I run mi e sometimes in harbor situations .. normally it is because the pla e we are is water short .. some islands in Greece are water short in the summer and I can see no reason to take their precious resources when I can make my own. Szme in Carib.

For those who eschew a wm and say in Carib that you can catch rainwater and fill your tanks. I have run across a few of those folks when they asked for water and I gave them some.

[Tellie]

As I always tell my customers. In theory you can drop the intake of your watermaker in a septic tank and make good water until you clog the pre-filters. But watermakers should be considered offshore pieces of equipment where the water is gin clear, as in the Carribean and elsewhere. Biscayne Bay has a lot of pollutants running off into it from the surrounding residential neighborhoods and in heavier weather, like we are experiencing this week, decades of pollutants from the bottom of the bay get stirred up as well.

[Chotu]

Originally Posted by Tellie

As I always tell my customers. In theory you can drop the intake of your watermaker in a septic tank and make good water until you clog the pre-filters. But watermakers should be considered offshore pieces of equipment where the water is gin clear, as in the Carribean and elsewhere. Biscayne Bay has a lot of pollutants running off into it from the surrounding residential neighborhoods and in heavier weather, like we are experiencing this week, decades of pollutants from the bottom of the bay get stirred up as well.

Which means?

Just an issue for the prefilters? Or something worse as pollutants get to the membrane?

[Pizzazz]

Another approach, especially if you have multiple tanks is to collect rainwater in one tank then run it through the watermaker to put in a cleaner tank. Alternatively if you get water from a dubious source, you can run it through the watermaker to clean it up (first remove chlorine which is a problem). Then we come to recycling septic tank water or at least number 1, I think they do it on the space station. But really, who wants to go there

[Tellie]

Originally Posted by Chotu

Which means?

Just an issue for the prefilters? Or something worse as pollutants get to the membrane?

Well the issue really is that there is no perfect pre-filter. I like the ones we sell the best, but if run long enough in dirty water (regardless of the contaminant) somethings are eventually going to get by them and start collecting in the input of the membrane and start clogging it up prematurely. If cheap filters are used the chances obviously increase that this can happen especially if run in dirty water to start with.

Most all watermaker companies will say that their systems are meant for clean water offshore with the standard pre-filtration that normally come with a boat based watermaker. If a customer insists on running their watermaker in dirty situations they need to understand that all boat base watermaker systems come with adequate filtration for clean open water situations. If they insist on operating their watermakers in dirty water they will need to look at additional filtration designed for that environment such as media filters.

[Cheechako]

Bottom line is you dont know where the pollution actually is, or what it is.. in harbor or out. Case in point, I witnessed a navy grey gov't vessel circling outside the French islands while dumping a very ugly liquid. It coated my boat in passing through the slick maybe 1/2 mile from them. The entire surface of the water for miles was an oily flat slick, but no rainbow coloration like oil. Watermakers rejects things right? and you need to flush them as a matter of course. I dont know if "pollutants" that aren't oily are an issue or not for longevity.

[a64pilot]

We make water twice a week, we HAVE to make water once a week, it’s not often that every week we are offshore.
It’s a gamble, like I said I had to change my membranes last year, prematurely, I’m sure because I made water where shouldn’t have.
But it wasn’t catastrophic, yes it was some money, not a lot really, but I didn’t buy the watermaker to ration water.
I’m just more careful where I make water now, but I don’t wait for gin clear water, I never, ever see that, not until we get to the Bahamas anyway.

[YANDINA]

We've done it frequently - - don't forget to reduce the pressure in brackish or fresh water.

Our biggest problem was the primary filter clogging up every 15 to 20 minutes at $$ each. We solved the problem with a $200 swimming pool sand filter. It had its own raw water pump so that with a couple of valves we could divert the output to overboard and backwash the sand filter as often as needed. Paid for itself in a couple of days.

[Chotu]

Great post, Tellie. Thanks for clarifying the details. Finally a definite answer to this question.

Originally Posted by Tellie

Well the issue really is that there is no perfect pre-filter. I like the ones we sell the best, but if run long enough in dirty water (regardless of the contaminant) somethings are eventually going to get by them and start collecting in the input of the membrane and start clogging it up prematurely. If cheap filters are used the chances obviously increase that this can happen especially if run in dirty water to start with.

Most all watermaker companies will say that their systems are meant for clean water offshore with the standard pre-filtration that normally come with a boat based watermaker. If a customer insists on running their watermaker in dirty situations they need to understand that all boat base watermaker systems come with adequate filtration for clean open water situations. If they insist on operating their watermakers in dirty water they will need to look at additional filtration designed for that environment such as media filters.

[witzgall]

Pre filters can be washed and re-used. If you are anchored in a tidal area with a decent current, just hang them off of the transom for 4-5 hours.

Chris

[PedroPuraVida]

If you’re anywhere near Dinner Key I wouldn’t. The water is so polluted with human waste. Everyone pumping overboard and nothing regulated there. It’s the Wild West. City could care less!

[a64pilot]

Originally Posted by witzgall

Pre filters can be washed and re-used. If you are anchored in a tidal area with a decent current, just hang them off of the transom for 4-5 hours.

Chris

I used to flush mine out too, then came to the realization that it’s very possible that I may be damaging them and not know it and be letting damaging particles through, so I decided that I would clean the 20 as it usually clogs first, but not the 5, that way if I damaged the 20, the 5 should still catch what came through.
Then finally decided that not using new filters was foolish, I don’t wash out an oil filter or fuel filter, do you?

However I did find out that not all filters are created equal of course, some of the less expensive ones are paper, the Culligan ones I got on line were and paper works, but clogs easily and if your the type to clean them, parser is easily damaged. So now I make sure I get polypropylene filters, and of course be sure you get operated ones as they have more surface area, the string would ones will clog fast.

[Cheechako]

Filters are always a dilemma. I use polypropylene wound string ones a lot at home with well water, they are cheap. I guess I fall in the "would rather change often than overspend and leave them in" category.

[sail4evr]

Originally Posted by SKMT

In my case I couldn't functionally "avoid" running the watermaker inshore (because I don't take my big boat offshore enough). So basically what I am trying to ascertain is if I would be replacing pre filters so often that the hassle/cost eliminates the advantage of installing a watermaker (for my specific situation).

Be helpful if anybody with local knowledge could chime in.

Sk around in your neighborhod for someone with a watermaker and how often they change their filters. Local advice is best advice.