I don’t know if sailing drives one to be independent and self sufficient, or if people with a leaning towards independence are driven to sailing… What I do know is that there is true joy for me with each step we take to remove ourselves from the grid but maintain the comforts of home.
The latest step in my Doomsday Prepper saga involves the ability to make fresh water from sea water. We have solar panels and a generator for power, enough diesel to run the generator an hour a day for months, propane for cooking, on board waste treatment, and lots of freezer space and storage space for food. The one on board consumable that drives us to shore every couple weeks is the need for water. With a water maker we can make as much fresh water as we want anywhere we have sea water.
There are two major paths that one may take in deciding what type of equipment to install. One type of unit comes completely assembled and you just need to bring sea water and electricity to it for it to make water. Spectra is a well known manufacturer of assembled units. Although these are great units, for me there are downsides too. First, the units are pretty big and require a fairly large space for installation. Second, they are quite complicated and require proprietary components to repair. And third, they are comparatively quite expensive.
The second type of unit is a modular water maker. In this type all the components come separate. The particular water maker we chose is called an AquaMaax. The design of the AuquaMaax allowed me to install bits and pieces in different areas of the boat as space allowed. In addition, all the components are non proprietary and available from many sources. Also, the unit is very simple and easy to maintain. At 40 gallons per hour we can make enough water for a couple of days in one hour, and the cost was considerably lower than an assembled unit.
One other big decision concerns whether to use A/C or D/C for the pressure pump. A/C makes water faster, but it requires a source of regular 120 volt house current. D/C is maybe more efficient, but uses lots of battery power and is more expensive. Since we have several alternatives for making 120 volt power (inverter, generator, main engine 200 amp alternator, and solar) we opted for the A/C option.
On course, it is quite a bit more work to install all the bits and pieces. The control panel, high pressure pump, boost pump, pre filters, and reverse osmosis membranes all need to find a home. We had some space in the garage that worked out great for the controls. The area behind the controls is inside the starboard steering pedestal to allow access to the plumbing and electrical connections.
The membranes are the “filters” that separate the salt from the water. I found a home for them under the shelf in the garage. AquaMaax made some special brackets that allowed me to mount the housings very close to the shelf and preserve the storage space underneath.
One thing a water maker needs is clear sea water. I mounted the pre filters, carbon filter, boost pump, sea cock, and strainer all in the aft starboard lazarette.
There are also various drains that needed to be plumbed over board. These I ganged up also in the lazarette and plugged into a cockpit drain. No pictures, but the fresh water produced by the system is plumbed to our forward water tank.
Oh, and there was the little matter of the need haul the boat to install a through hull fitting to bring the sea water in for the water maker to use. We could have shared another fitting and avoided the haul, but we had some other bottom work to do anyway.
I did deviate from the plans in a couple of areas. First, the boost pump is drawn in the manufacturer’s schematic on the suction side of the controls. This looked like it would not work to me since my control panel is above water line. I moved to pump to directly after the sea cock. This location will provide the flooded suction that the pump needs for my installation. Second, I put a tee and valve in the sample line. It important that the sample discharge always be unrestricted so the tee splits water between a line to overboard drain and a line to my new sample valve. When the new valve is closed the sample water runs overboard while the system is starting up. When I want to prove the product water is good, I open my new valve, fill a cup, and test it for purity. Just the difference in head between the new sample valve line and the overboard sample line provides plenty of pressure to fill the cup when the new sample valve is opened. When it measures pure, only then do I switch over the main valve to fill the storage tank.
At the advice of another 473 owner, I plumbed the water product right into the fresh water manifold. I had an empty spot because I had switched the aft starboard tank to fuel, but you could plumb into the end of the manifold to supply all 4 tanks too. I had a very difficult time trying to route the water maker outlet tube from the manifold back to the water maker. I finally hit on the idea of using the unused aft water tank tube as a conduit for the watermaker tube. I just pushed the small tube into the bigger tube and the tube went aft towards the water maker just where I needed it. One important point: THE VALVES TO THE WATERMAKER AND ONE TANK MUST BE OPEN WHILE MAKING WATER OR THE PRODUCT TUBE WILL SPLIT UNDER THE OUTLET PRESSURE.
All and all the install was straight forward, but quite time consuming. In addition to mounting the hardware, the system requires connections to many other boat system. A/C power for the high pressure pump, drain plumbing, fresh water purge plumbing, fresh water product plumbing to our storage tanks, sea water supply and filtration, and D/C for the boost pump. Although the kit was pretty complete, the install still involved uncountable trips to Home Depot, West Marine, and Ace Hardware for the bits specific to my plans. My buddy Chris and I bought the AquaMaax units together in Annapolis. Chris wanted to get his install done before heading to BVI, but Sandy cut into his timeline. Now he is scrounging for bits in the land of no Home Depot. Hope you’re finding the parts Chris!
Operationally I am quite impressed. We have made a couple of tanks of water so far and although the system is fully manual, it is very easy to operate. The instructions are good and the vendor has been quite helpful with advice when I had questions.