Running a Watermaker Inshore?

[stormalong]

Put your sea water pickup as low as possible. Oil will destroy your membrane instantly and no filters will stop it. Oil stays near the surface. Don't run the watermaker when the water is churned up. You also don't want air in your pump and a deeper intake helps there too.

[Emouchet]

Been running my Rainman accross the bay in the Stadium achorage and at No Name Harbor last december and january before heading to the Bahamas.

Filters are getting dirtier there faster than in the Bahamas, but beside that nothing wrong. Fresh water out of the membrane was 207-220 ppm.

Just make sure you do not flush afterward with water that includes chlorine (tap water). That would kill the membrane in no time. I always backwash using the output from the watermaker. Backwashing required about 10 liters, so why not doing it every time?

[Captn_Black]

Originally Posted by SKMT

I live on the hook in Miami. Been debating a watermaker. I've read conflicting reports about running a water maker inshore. Some claim you gotta be out in the deep blue. Others say no problem in an anchorage. Here in Biscayne Bay, the water is basically never dirty from run off, but when the wind blows, the water clouds up to a few feet clarity. On the other hand, there are regularly days where the clarity is 6-10ft where i anchor.

I'm assuming the worst that can happen is i clog up pre-filters. I'm just wondering how often they would be clogging, assuming I tried to pick my days and just make water when the clarity is higher?

Miami? Not a good idea imo, I would say that ideally you would want around 3m visibility to avoid problems. Last time I was inshore in Miami it was about 20cm visibility and smelled of swamp.

[R2boat]

Watermakers need to be run just like your boat’s engine, yes you may have to change out prefilters more often but a lot cheaper than a new membrane or a pump rebuild....20 years of experience with a Spectra....do not be so timid

[Pizzazz]

Repeating the above, watermakers like to run as often as possible. You can definitely run it insure or in the marina as much as you want. If the filters become clogged, replace or add more stages, ie 20+5 microns.

Oil stays at the surface, not near the surface, so it is rarely a problem if your intake is a couple of inches down. Most are about a foot down.

Organic matter is not an issue because it gets caught in the predictors mostly. The membrane does not let through any viruses or bacteria (think about it, it is supposed to stop NaCl molecules vs. viruses that are probably 100x bigger.

The only things that go through the membrane are heavier elements (smaller atoms), ie copper, etc. It will not kill you but don’t over do it. In case, if in the marina you can buy drinking water use the watermaker water for everything else.

SV Pizzazz

[SKMT]

To reiterate...I understand a watermaker needs to be run regularly and that it can be run anywhere -- just a matter of how fast prefilters clog.

My internal debate is that my trawler has 200sqft of roof space. So all I need to do is install a collection system and then every cumulative inch of rain, would yield 100 gallons into my tanks. Based on avg rainfall in Miami, there would be a few lean winter months, but the rest of the year we're talking 300-1000gallons/month automatically without me even thinking about it. All that water without paying thousands for a watermaker, manually running/backflushing it every several days, constantly changing prefilters, etc.

But it would be stupid for me to install the collection system, if I'm gonna end up wanting a watermaker, so I'm just trying to mentally game it out now, and figure which makes sense for my specific eituation as described. If it wasn't for the couple dry winter months, I think collection would be the no brainer, but because of that I'm on the fence. Also, if I get a watermaker, I will go full waterhog and install a big old used residential washing machine.

[Dsanduril]

We have both!

Rain is free and really pretty easy. But if it's going into your tanks you kind of want to check it ahead of time, that sometimes means getting up on the roof and scrubbing it when the rain starts. And it's not always on your schedule. You hear it start raining at 2am, you know you need water....

You can run a watermaker more on your schedule, but there are costs involved. We collect our rainwater, and when it is plentiful is when we do the big loads of laundry or take a long shower. We use the watermaker for the drinking water and general day-to-day stuff.

[slug]

Originally Posted by SKMT

To reiterate...I understand a watermaker needs to be run regularly and that it can be run anywhere -- just a matter of how fast prefilters clog.

My internal debate is that my trawler has 200sqft of roof space. So all I need to do is install a collection system and then every cumulative inch of rain, would yield 100 gallons into my tanks. Based on avg rainfall in Miami, there would be a few lean winter months, but the rest of the year we're talking 300-1000gallons/month automatically without me even thinking about it. All that water without paying thousands for a watermaker, manually running/backflushing it every several days, constantly changing prefilters, etc.

But it would be stupid for me to install the collection system, if I'm gonna end up wanting a watermaker, so I'm just trying to mentally game it out now, and figure which makes sense for my specific eituation as described. If it wasn't for the couple dry winter months, I think collection would be the no brainer, but because of that I'm on the fence. Also, if I get a watermaker, I will go full waterhog and install a big old used residential washing machine.

In a city environment rain water is polluted .... hydrocarbons, particulates

Be alert

The same can be said of the urban seawater for a water maker

[SKMT]

Originally Posted by Dsanduril

We have both!

Rain is free and really pretty easy. But if it's going into your tanks you kind of want to check it ahead of time, that sometimes means getting up on the roof and scrubbing it when the rain starts. And it's not always on your schedule. You hear it start raining at 2am, you know you need water....

You can run a watermaker more on your schedule, but there are costs involved. We collect our rainwater, and when it is plentiful is when we do the big loads of laundry or take a long shower. We use the watermaker for the drinking water and general day-to-day stuff.

The way I would set it up, is it would automatically drain into the tanks, so need need to rise out of bed to collect rain.

My thinking on it being a binary choice is if I have the watermaker, it needs to be run weekly or pickled, so not much point putting rain in tanks then. Plus for back flushing, the rain water prob not pure enough cuz whatever comes off roof with it.

Drinking water is really the least of my concern, the water is for showering and shitting in, so not too concerned about any impurities on my roof. And if im cooking with water, its getting boiled anyway. Also, with the amount it rains in summer, im sure I could do the few loads of laundry I have with rainwater. Winter would be the lean months. But i could ration and/or jug water in a pinch if it was just 1 or 2 months per yr on avg. Seems thatd be less work than running a watermaker 75 times a year, whilst clean water is literally falling out the sky on my roof.

[a64pilot]

Surprised no one has posted this link. It discusses the question that this thread asks, and comes from possibly a better source than most of the YouTube “experts”
https://youtu.be/aVAE5ZOKWAk

[SKMT]

Originally Posted by slug

In a city environment rain water is polluted .... hydrocarbons, particulates

Be alert

Miami Beach has some of the cleanest air in America. The max elevation is about 10ft, and there's a prevailing East wind off the ocean -- any pollution is blown west instantly.

Not that I'd be concerned about it regardless, but definitely not here.

[Cheechako]

I always ran mine wherever I was. Even in dirty harbors in Puerto Rico or the DR. But I tried to make water underway as my first option. If at anchor in one place for 5-6 weeks, you don't have a lot of choice. Just keep the pre filter clean.

[slug]

Originally Posted by Cheechako

I always ran mine wherever I was. Even in dirty harbors in Puerto Rico or the DR. But I tried to make water underway as my first option. If at anchor in one place for 5-6 weeks, you don't have a lot of choice. Just keep the pre filter clean.

What is the location of your UV sterilizer ?

Are you using sand pre filters ?

[Cheechako]

Originally Posted by slug

What is the location of your UV sterilizer ?

Are you using sand pre filters ?

Neither. Water maker takes out bacteria and virus', most everything really.. Inlet ~ 1.5 feet below water surface.

[waterman46]

Originally Posted by SKMT

To reiterate...I understand a watermaker needs to be run regularly and that it can be run anywhere -- just a matter of how fast prefilters clog.

My internal debate is that my trawler has 200sqft of roof space. So all I need to do is install a collection system and then every cumulative inch of rain, would yield 100 gallons into my tanks. Based on avg rainfall in Miami, there would be a few lean winter months, but the rest of the year we're talking 300-1000gallons/month automatically without me even thinking about it. All that water without paying thousands for a watermaker, manually running/backflushing it every several days, constantly changing prefilters, etc.

But it would be stupid for me to install the collection system, if I'm gonna end up wanting a watermaker, so I'm just trying to mentally game it out now, and figure which makes sense for my specific eituation as described. If it wasn't for the couple dry winter months, I think collection would be the no brainer, but because of that I'm on the fence. Also, if I get a watermaker, I will go full waterhog and install a big old used residential washing machine.

Since you have such a good rain collection potential, why not install that, it is cheap and easy compared to installing a watermaker. During the winter months if you run low on water, pick some up when you re-fuel. Assuming you are not just sitting on the hook going nowhere.

Try that approach one season, see how it works, and then you will know if you need a watermaker. They are great, but consume power and require tender loving care all the time, unless you pickle it with chemicals.

We had a watermaker on the west coast, where it never rains, at all, during the cruising season. It was necessary there, but when we got to Panama and the Carib, we met many who rely on rainwater for their needs.


Our 1999 Spectra watermaker developed a cracked block in the pump, for the second time, last winter. We got along fine without it just filling up at marinas. We average one marina stop every two weeks or so. We have 185 gallons water capacity, and it was enough easily for two or three weeks with showers every day. We don't flush heads with fresh water of course. We have a washing machine on board, but it only is used when we can hook it up to dock water.

We don't have rain collection, but after we got to the east coast of Central America we learned about rain during the cruising season. It seemed weird, but then we wished we had a collection system.