Need Advice on watermaker

[rwappleton]

Good Morning All,

We are in the hunt for another Hatteras again. Looking in the 48-52 foot range. Admiral says stairs to the F/B so newer CPMY's

One of the requirements for us is a watermaker and fuel polishing. Most of the boats we are looking at do not have them. Fuel polishing is a no brainer just a matter of proper installation. The watermaker is something we know very little about so we need as much education as we can get from this wonderful site! We do not want to make a 5-8K mistake.

Separate subject one of the boats we are looking at has an inop (Onan) genset. What are new ones going for these days and would it be worth considering a rebuild/reman unit? I know size matters and if replacing we would go with one that would easily power everything.

Blue skies and calm seas

Russ Appleton

 

[Scarlett]

Most 110 or 220 volt water makers are just assembled from readily available parts, a Cat pump, a membrane a low pressure pump and hoses and valves, which can be done for about $1500. Which adds to the cost are automatic flushing systems, pretty cases and the assemblers mark up. So I am not real sure the actual brand you buy makes a lot of difference because the basic parts are all the same. I have had experience with systems from basic $1500 units up to $10,000 units. Of course cost also rises with output. A single membrane gets you about 20 gallons per hour and the basic Cat pumps will easily handle 2 membranes or about 35 gallons per hour. John

 

[Boatsb]

Whats the need for the watermaker. Are you traveling outside of the US where water is expensive and questionable or hanging on a hook a few days at a time?

The newer units that are automated make life easier. You can manually operate the basic components but who wants to? Make it a transparent part of your boating.

Remember they use power. You need to plan on making water with the generator running so plan for one large enough to fill the tanks on your daily generator time.

 

[Pascal]

Spot on about Watermakers. You don’t want something too complex or using proprietary parts like Sea Recovery. I ve had bad experiences with Sea Recovery especially their control screens. Multiple failures and then when they changed the design you had to replace the main control board and add a bypass on the HP pump. A $5k “upgrade”

Automatic fresh water flush can easily be added, it s just a timer and valve.

As to gen I m really not a big fan of Onans. We have two 27.5 on the boat I run (2009 models) and I have had many issues with sensors and raw water pumps. Even new pumps and clean system don’t put out enough water to effectively muffle the exhaust. Runs cool but loud. I d look at Northern Lights... the gold standard. Or Westerbeke Price depends on size obviously.

 

[Dan Mapes]

I would also recommend avoiding any mfg that uses a proprietary membrane that does not fit other pressure tubes. Next go with a unit that is larger than you think you need. My best guess is that if they say it is a 300 gpd (gallon per day) water maker, that is if it runs 24 hours continuous.

You do not want a water maker running 24 hours. They are noisy!

If you are doing laundry etc. consider your fresh water tank size, and how fast your wm can fill the tank again. Don't bother with 120v, use 250v and completely avoid dc units.

For that size boat I would spec at least 25 gph (gallons per hour). If you will have company add to that number. We lived aboard in the bahamas with 10-12 gph and did laundry etc.. We wished we had at least twice that on our 43 my.

Edit:

We also installed a test spout by the kitchen sink with a switch valve under the sink. I'd set the valve prior to starting the wm, get downstairs and set the high pressure pressure, go upstairs and wait a few minutes. Once the samples came out good I would change the valve so it dumped into the tank. When the tank was full I would set it to the sink so the S.O. could fill water bottles for the fridge etc..

 

[Finalee]

Check these guys out. https://www.cruiserowaterandpower.com/

Since you have a generator these will produce 40 plus gph. Easy to find parts, and the owner has a good reputation for trouble shooting.

Note that they are designed for use in blue water. Dirty water causes membrane problems.

This is on my to do list too.

 

[jim rosenthal]

Pascal, can you comment on this? I read, years ago, possibly in Passagemaker, that RO watermakers need to be run frequently in order to stay functional and that many people buy them too big- that it's better to get a smaller one and run it more often and more hours? Is that true? I've read accounts of people having to dump FW overboard because the tanks were full but the RO plant needed to be exercised, basically.

 

[Pascal]

I don’t think it s true. Yes like everything it s good to use them but I’d they sit for a while they either need to pickled with a special solution or you need to fresh water flush it weekly.

When we don’t go to the Bahamas for a couple of months, we don’t use the WM but the auto flush kicks in weekly. Never had an issue in 15 years. I usually get about 5 to 6 years out of the membranes

Note that you need a charcoal filter on the Fresh water flush line to eliminate Chlorine found in city water

 

[tomrealest]

When I bought my Hatt 18 years ago, the PO who was a Naval Academy graduate who investigated everything before he did anything had installed a Watermakers. Inc. out of Ft Lauderdale. He was going to the Bahamas every year. It has worked flawlessly for me. He had also installed a 20 kw Northern Lights generation. Just replaced the raw water pump. No other issues in my 18 years.

 

[scottinsydney]

We replaced a previous owner's old watermaker with a simple and inexpensive "build yourself" system from www.seawaterpro.com The owner's name is Mike.

Its worked very well and solves the problem of us running out of water on a two week at anchor holiday.

A watermaker is very expensive to just make water using the genset, so use marina water if you have it available.

I dislike cleaning/changing the filters every few days when its in use. Also the membrane needs to be swapped out every four years regardless of litres of water produced. We run an automatic fresh water flush every 3 days for a minute. Then once a year the membrane should be flushed with a special cleaning solution. But product water flow drops as the membrane ages.

But, for holiday use away on the anchor with the missus and kids and water activities, a watermaker is fantastic. Next time, I would definitely purchase a two membrane 35 gallon system as your genset time is effectively halved and maintenance is the same.

 

[carolinacoast]

x2 on cruisers RO wm. If we truly go to the Exumas, post covid ,the 40 gph, 240V is the spec. You want to make water while you need the gen for meal time. Noisy, so you want to make a lot.
PO had one on here for the bahamas, and added a 2nd gen. 2 will fit on a 53. 2nd is a 12.5, if you need that kind of redundancy.
On true bluewater sailboats that I have been on, I only saw 2 brands. Both posted already. NL and WB.
A charter operation in West End tortola uses only Northern Lights now. Owner told me that charters run 200 hours per week, and downtime is what matters, not cost. When the gen is down, the boat is down, and that is the REAL cost. They had tried many brands over the years.
Swan sailboats for many years came standard with Westerbeke gen and yanmar power. Those truly cruise the world.