P42 Watermaker Install

[Jim_H42]

I'm thinking about/researching installing a DIY water maker. The 120v system components could be split apart over the various compartments of the boat.

Any insights from P42 owners with WMs is greatly appreciated.

 

[Terry Cox]

Any insights from P42 owners with WMs is greatly appreciated.

Good morning, Jim. Little to no insights here. With 150 gallons of water tankage, never had a need due to ample PNW water sources. Some merit if planning a serious off shore cruise to Asia, etc., but no plans there either.

 

[capta]

I gathered the parts and assembled my 43 gph watermaker on Skipping Stone.
The first thing I did was find a good deal on the high pressure pump, as that is by far the most expensive item. I was able, after many months of searching, to find a nearly new one at less than half price, from a watermaker manufacturer who had experimented with it, but found it unsuitable for their project. Then it was pretty simple to assemble the other bits and place the pieces where space was available. I used Pex fittings for all low pressure lines (blue for fresh, white (I'd have preferred green) for salt water.
It worked trouble free for about 7 years, only needing a few inferior quality SS fittings replaced. I did incorporate a battery powered TDS meter into the system (under $25.00), so I could keep tabs on that without messing about testing the water. I ran a 12vdc feed pump and a 110vac high pressure pump.
There a lot of folks who get all fussy about the water quality from non-pristine seawater, spending money on UV systems, but from all my research, the membrane will not pass anything biological (or otherwise) that could be harmful to humans, and I used my normal tanks. That is not to say that it can be run in oily or fuel polluted water, and never in freshwater.
I figured it saved me around $3k over a premade unit. I still cannot enjoy a glass of water here, even after filtering, after living with RO water for so long.

 

[mbaker]

My question is where would you install it for access for service? There are two large voids under the setee, but that does not lend to easy access.

 

[Jim_H42]

Thanks capta - your install and research parallels my thinking as well. I'm thinking for around $2.5K I could build a system...

mbaker. - your question is why I created this post. From my research it sounds like the pre-filters need easy access - I was thinking of installing 10" units in the bilge with the HP membrane housing & HP pump under the port seatee. Other ideas are to leverage the area under the saloon table (I wrote up in the P42 improvements section how I got access to this area). I've also thought about reconfiguring the large area under the vee-berth as the existing draws are very wasteful.

As Terry Cox noted we have 150g of water tankange. I'm trying to decide if a WM would greatly improve our life on an extended Bahamas cruise and what are the installation options.

Thanks

 

[Neffilicious]

We installed a CruiseRO 30gph unit in our ‘90 P42. We installed the high pressure pump in front of the water heater and the membranes infront of the high pressure pump. This took up a fair bit of space under the port settee but it allowed for relatively easy service of the system while still allowing storage of smaller items around the membrane housings. The pre-filters are installed behind the port settee seat back aft of the rigging strut. I cut access panels in the seat backs for easy access to the filters and boost pump. The control panels were installed in a box I built from teak veneered plywood in the space occupied by the wine bottle storage provided by the Hunter factory. The boost pump is located beneath the control panels.

 

[mbaker]

Nicely done. Good option. We have been to the Bahamas and never had an issue because of the tankage we carry. We did ferry jugs once or twice but only to stay on the side of caution.

 

[Neffilicious]

We spent 5 months in Bahamas before heading south. We found water reasonably available but since we also have a washing machine onboard, we really needed the WM. Not being tied to marina water allowed us to spend as much time as we wanted, where we wanted. Not having to schlep water jugs back and forth is a freedom we greatly enjoy.

 

[Jim_H42]

Neffilicious - beautiful install! I didn't realize there was so much space behind the seatee backs. Sounds like you have a self priming boost pump. Did you install a new thru-hull or leverage an existing? If I go ahead with a WM, I'm thinking of converting the heads over to fresh water flush and would leverage the aft head thru hull. Thanks for the pictures and idea of leveraging the liquor storage area.

I agree with others that water is available in the Bahamas. My motivation is to try and improve the quality of onboard life for my wife by eliminating my constant reminders to conserve water and to provide more freedom to explore.

 

[Neffilicious]

Jim_H42 - thank you. I put a bit of time measuring available space in different places while trying to keep hose runs as short as possible. Also a priority was easy access to the control panels whole making their install look like it might have been a factory option, or as close as I was able with limited wood working skills and tools.

The boost pump is self priming. It’s a Jabsco diaphragm pump without a pressure switch so there’s no risk of it cycling in use. I used the aircon inlet through hull for my seawater source. I originally fitted a Y-valve but after we started cruising I fully decommissioned both AC units (removed the forward entirely) and now the WM has that through hull as it’s own.