Watermaker for 2000 340 DA

[Bounty]

Well, the only amenity that my 340 Sundancer is really missing is a watermaker. For a 3-7 day jaunt over to Catalina Island, the one weak link in the boat's endurance is the constant need to ration water. I am looking at putting in a watermaker, and have received some interesting specifications. Anyone have comments about such a project?

 

[Four Suns]

This has been a big issue on my boat as well since there are 2 adults and 4 kids (and kids sometimes bring friends) and we can easily chew through 100+ gallons of fresh water in a day.

This is what I found in the research I did... Not saying it is right and these are the opinions I formed after doing a lot of reading on the subject. I'll preface to say I don't have one installed yet as my Bahamas trip and general boating excursions have been postponed a little due to a dog-meets-car issue (another post).

I will say that what you get will depend on the size of your generator and how long you plan on running your generator per day. My conclusions are based on the fact that I have a good size low-rpm diesel genny (very quiet) on the boat and it is running constantly if the boat is not plugged into the dock since my fridge, freezer, etc. is all 110v (and yes... all night at anchor also). Power requirements are generally not an issue with my set up.

I generally put these watermakers in 3 buckets:

1. Low energy/energy recovery models with automatic/electronic control
2. Conventional models with automatic/electronic control
3. Conventional modes with manual control

The concept of these things is pretty simple in that you have a membrane with high pressure salt water on one side and and fresh water produced from water sans salt on the other side of the membrane. Add a high pressure pump and pressure/flow regulators to the system and that is a basic watermaker.

The "conventional" watermaker models are typically the 110/220v items that flow a lot of water through the membrane but at a constant high pressure. Very simple systems with manual control are sold by companies like Echotec ( http://www.watermakers.net ) along with a whole host of smaller companies that put the basic parts together and have no electronics to fail. They have manual valves and switches you turn on and off and their sales pitch is that they are easy to fix with off-the-shelf parts and very reliable. The key here is that there is a high flow of water past the membrane and the pressure is constant. The high flow of water essentially keeps the saltwater side of the membrane flushed of high-concentrations of salt when in use. However, you do have to monitor the pressure, adjust systems manually, and do fresh water membrane flushes, etc. all on your own on a schedule and if you don't, the system will get hosed.

Companies like HRO Systems, and a few others, have added electronics to manual conventional systems so that it monitors salinity, automatically adjusts pressure, periodically back flushes with fresh water, etc. so it's basically a switch to turn on and it works. You still have to keep up with pre-filter, and membrane maintenance but the idea is to take a lot of the manual operation away from the user. Again, these systems have high flow of water and constant pressure to keep the membrane flushed when in use.

The problem with the conventional systems is that they need a lot of juice to run. To address that, some manufacturers have introduced "low energy" models (HRO, Sea Recovery, etc.) where there is a pulsating pressure used on the membrane instead of a constant high pressure/flow on the membrane. These systems can work on 12v as well as 110v. This reduces energy and water flow but there are issues with them that seem to be popping up. First off, the reduced raw water flow on the membrane can clog the filter faster. Second, the pulsating nature of the pressure puts a lot of strain on the filter and seals compared to a constant high pressure. Third, all the electronics to make this thing work can (should I say "will") fail someday. Fourth, even though they are "low energy", they will still drain a battery and you probably will still have to run the genny. Here are some comments on the HRO low energy model: http://www.westmarine.com/SouthPacific06/RandysReviews/RandysReviews.htm#Misc

So, you need to ask yourself a few questions:

1. How much water do you need a day? I'm going with a 700 gallon per day conventional system with some of the automation electronics so the thing will only run 5 to 6 hours per day and meet my water needs. You don't want it running 24 hours per day. If I was an offshore sailboat, I would nuke the electronics part so I could fix it if I had to.

2. How much energy can your genny/battery bank handle. For a smaller boat, one may have to go with a low energy model or else the engine alternators/genny can't keep up with the power demands. This will depend on how much water per day you need.

3. How much room do you have? They make self contained units and modular units. Modular units let you put the pieces where you have room versus having it all in a generator style box.

4. How much will you use it? Watermakers appear to be strongly in the "if you don't use it, it will break" category. When it is not in use, it has to be pickled properly.

5. Installation. I've talked to a shop about an install and I've talked to people that have put them in themselves. It's fairly involved to "get it right" on the power and plumbing but not an impossible DIY for an advanced DIY person but it's a borderline thing. You will need a new thru-hull intake and another thru-hull exit and the right size for the thing to work correctly plus all the power issues addressed correctly. I personally have to have an experienced shop do the thru hulls since I have a cored bottom.

Again, these are my opinions and I have a big ole' notebook on this stuff... Probably be easier just to tell the kids to stop taking 20 minutes showers... maybe not.

 

[Bounty]

Great post, Gary, and thank you.

I am looking at the Village Marine 400 GPD AC powered unit. It draws around 15 amps and produces about 16.6 GPH. Our typical routine is to run the genny two hours in the morning and two in the evening, so this should pretty much fix us up fine. The amp drain should be well within the comfort zone of our 4.5KW Westerbeke, and gennys like to be run with a load anyway. Wish me luck, grin. :smt001

 

[Overextended]

How much does something like this cost on average?

 

[Bounty]

How much does something like this cost on average?

It varies wildly with what you get and who you get it from. Looks like around 8 large for the one I want.

 

[Four Suns]

I have a qoute for a little over 10K installed... it's a big expense and commitment for maintenance...

Looks like the Village Marine unit you are looking at is about where I decided to go. Conventional watermaker with some "helper electronics". I'll have to get more info on these guys for the 600 GPD model. Thanks for the link.

Gary

 

[Michael La Prairie]

It varies wildly with what you get and who you get it from. Looks like around 8 large for the one I want.

Howdy from Vancouver, just wondering if you ever installed your watermaker and where did you install it. We have a 360 sundancer (limited space), thanks Mike

 

[dtfeld]

Just a though if your an occasional user. a portable unit might make sense

https://www.rainmanusa.com/

 

[Michael La Prairie]

yes been looking at, hoping to have it installed but as you know, not alot of available places to other than the back storage (wich we have a BBQ which takes up a tone of space

 

[tc410]

Howdy from Vancouver, just wondering if you ever installed your watermaker and where did you install it. We have a 360 sundancer (limited space), thanks Mike

This is a 14 year old post.... you may likely not hear back from the OP on this, but possibly others since that have tackled this project may chime in. The OP was last seen a decade ago....