La Paz, Baja California Sur, Mexico
I must admit to a certain sense of accomplishment for Mags and I, in being able to write that address. We arrived on 10-Dec-14 to get Mags on her flight to Vancouver for some long awaited grandma time. I feel a bit like the kid who got a detention and had to stay after school to finish his homework.
|Neighbour's mast and La Paz from our mast|
As most of you know, we went to sea in an unfinished project. But in my defence, if you wait until it is perfect you will never go, get the safety stuff done and go. In the nineteen days since arriving, I have been busy getting to know La Paz and, more importantly, sourcing the marine suppliers and food stores in a fairly large city. The bike has been working hard going from the big box stores in the South and East and the numerous marine stores in the marina area, to the small, old hardware and specialty stores of the old town, north along the Malecon. You know I am loving it…..
So after washing a month’s worth of salt from the boat and helping to tote laundry, I managed to plumb a dual filter canister system for our dock water hose. This was especially sweet because I got the two canisters at the Club Cruiseros swap meet for a bargain price. After throwing the old filters, fittings and hoses away and some elbow grease on the canister housings, new filters, new fittings and potable water hoses, it looked great. The test was less than stellar. I used a charcoal filter and a 5 micron filter and did a Total Dissolved Solids (TDS) test and got a 625 reading. 500 is the FDA target number but I had never bothered to test any of the previous marinas so I have no basis for comparison. The people on the dock are mixed between buying delivered bottled water for their tanks and those who use basically what I have made and adding a quantity of bleach for chlorination. Consensus seems to be 1 tablespoon bleach per every 5 gallons.Well, the fish in our marina seem to think the sea water is pretty good. They thrive, the water is quite clear, several feet of good vis and the tide does a good flush twice a day. Furthermore, the TDS meter mentioned is just one piece of a pile of stuff we bought as a group of Bluewater Cruising Association members who wanted to build their own watermakers with readily available, off the shelf parts. Credit goes to Colby Vaughn, Dennis Giraud and John Gleadle for spearheading this thru design and acquisition.
With filtration not working on the marina water, the watermaker became my priority Xmas project. Well, today the system produced water! The TDS readings after the requisite start-up flushing of the reverse osmosis (RO) membrane were 85 ppm on the in line meter and 97 ppm on the hand held meter in a sample collected in a glass. What, is this more criticism of my dish washing abilities – the glass was still dirty? Or just the variation of the meters. Whichever, the water tastes great! I made a measured gallon in 3 minutes 13 seconds and then added about 6 gallons to the main tank on the boat. Sweet.
Now, that is probably all that most of you want to know about watermakers so you can stop reading. For the few of you wanting to know more: design considerations, installation location issues, and so on, I will continue. I love the convoluted details ‘cause the devil lives there….
|Watermakers are like real estate, it's all about location|
|The challenge - where to put a 40" long Pressure Vessel|
Welcome to the Devil’s Lair
First a disclaimer, my knowledge is theoretical, the only system I have built is Kanilela’s and I would possibly make some fundamental changes to what I did. I have never owned a watermaker and never sailed on a boat that had one. I was of the conserve and minimize the systems which are prone to failure school of sailing. On Tangerine we intentionally sailed into squalls. It was simple, they had water and we needed water, or soon would, on a 45 day crossing. Her storage capacity was not sufficient to carry enough and we did collect a lot of water. Last summer in the BC Gulf Islands we had a new revelation. We could not fill our tanks at all of the marinas both due to shortages they were experiencing and at some their wells held only sulphur water that you would not want in you tanks. If it was this bad in the rain forest area of the Pacific Northwest, the Pacific Southwest to we Canadians, then how would we fare in the Caribbean?
Purchase a Brand Name System or DIY?
We have all heard stories of certain brands whose filters are a unique size and are not readily available other than through the manufacture, and priced accordingly. Another theme, encountered a little later in the life of the system, is pump or motor replacement parts are propriety parts and again, priced accordingly if the company still produces them. There are some other, more recent entries into the market, who have recognized the off the shelf philosophy and unless you are wanting to build a very specific system then I would recommend looking at one of them. Start with Cruise RO. Secondly, unless you have a fairly large boat and can fit a fully constructed unit that is essentially plug and play, you will need to do a lot of individual installations of the various parts whether Name Brand or DIY. It was the uniqueness of our various systems and the desire to build with readily available, from the shelf parts coupled with the savings from some level of bulk buying because there were eight of us committed to the project that led us to go forward with the project. In the end, possibly that should read “Eight of us that should have been committed”.
Quantity of Water You Require
Most of us were wanting production in the 20 gallons per hour range and a few wanted more, the 30 gallons per hour range. This had all of us using a very common membrane size of 2.5” diameter by 40” nominal length, either singly or two in series. We all chose to go with the Chinese made pressure vessel as opposed to the more expensive US made vessels. The Winder name is well regarded and used throughout the world in countless large commercial systems but what we assumed was a 3/8” NPT thread was probably a British or metric standard. Although we tried all available fittings, none were perfect so we had them re-machined to the US NPT standard. I am not at all disappointed with the product because we met Ed, Tony and Herman in Chula Vista California, as noted in a previous post, getting the machining done. The membrane was the Dow SW30-2540, a readily available membrane in the $180 range.
|Only the back half of the lower shelf was used|
|The membrane housing rotates down using only the top back corner space of the drawers|
Quite simply: belt drive from you engine, an AC motor or a DC motor. There were a couple of boats that had the space to do the pump driven directly from their engine which is probably the most efficient energy transfer but does necessitate running your engine to make water. An AC motor driven from a generator or the main engine thru an inverter was the most common choice. Several boats had generators already built in with capacity to run the pump. Another choice, which is the mainstay of the Cruise RO watermakers, is to use a Honda EU2000 to power the motor. It has the capacity and is economical on fuel. Most of us carry 4 cycle outboard motors so gas is not an additional fuel, only a little more quantity is needed. For most smaller boats the Cruise RO system with the Honda is probably the best way to go. My reservation was only that I did not want to be that guy in the anchorage who destroys everyone’s peaceful afternoon/evening with a running genny.
The 12V DC motor option is usually limited to much smaller production rates than our 18-20 gallons per hour, typically in the 6 to 11 gallons per hour range to keep the motors smaller and the amperage draw down. These tend to be less common membrane sizes and the pumps, generally are proprietary which defeats the original objective. Kanilela has 2 – 250 Watt solar panels with an 850+ Ahr battery storage capacity. The 1HP DC motor draws 80 amps to run the 1500 PSI pump. The numbers seemed to work so I ran with it. I should add, I was the only one who did. This June and July, cruising Vancouver Island with sunshine from 4:30 am to 10:30 pm the solar panels hardly noticed the 4.8 Amps for the Nova Kool frig/freezer (yes, I confess, I’ve become a power pig!) that I was certain I had the right combination for the watermaker – let the sun do all the heavy lifting…..
|John Gleadle did a great job on the panel|
Well in Mexico in December, the sun is surprisingly low on the horizon even though we are at the tropic of Cancer, and sunrise is about 7:00 am and sunset is about 5:00. Throw in a few clouds and an anchorage that casts the masts shadow onto the panels and those Ahrs become pretty elusive. We have a 100 Amp Balmar alternator so I can produce the Amps and on this trip with light airs the motor has been used a lot so the power was available.
Today, to prove the system, I used shore power through the Zantrex Prosine 2000 to charge the batteries. It was at 135V AC putting out 50 Amps (these Mexican Marinas are the opposite to our Canadian Marinas with their constant low voltage brown-outs) and with some additional input from the solar panels the system was at a slight negative production running frig/freezer, the lp feed pump and the hp pump. The system works. I have more real estate to be able to add to the solar array and wind turbines are getting near silent, so those are viable future options. I do not have a cruising kitty to support more AGM batteries nor do I want to bench press their 130lbs into some yet to be found location on the boat. For now, I guess we keep chasing South to get that sun more overhead and motor onto and off the hook. It sure is nice water.
My Parts List:
1 – 1” bronze ball valve
1 – Vetus FTR140/19 Sea Strainer
1 – Johnson CM30P7-1 12v feed pump
1 – Check valve
3 – Watts 10” Filter housings
2 – ¾” 3Way valves
2 – hose spigots
1 – 1HP Leeson DC motor Model C4D17FK28
1 – WM Series General WM2315C 1500 PSI HP pump
2 – HP hoses 1 – 6’ 1- 8’
1 – Winder 2540 HP Membrane Housing
3 – Dow Sw30-2540 Membranes (2 would have been good enough)
1 – Pressure Valve
1 – Stauf Pressure Gauge
1 – Accutec Vacuum Gauge
1 – Dwyer GPH Flow Meter
2 – Cole Hersee 58312-R4 SPST w/LED switches
1 – Hobbs/Honeywell 98303 hour meter
1 – panel fabricated to fit all the controls and gauges
1 – HM Digital inline TDS Monitor Model SM-1
1 – HM Digital hand held TDS Meter Model TDS-4
1 – ½” vent fitting as a thru-hull drain
1 – sink spigot for testing, start-up drain and filling water bottles
6 – Charcoal filters
12 – 20 Micron Filters
12 – 5 Micron Filters
Endless ¼” OD tube and slip fittings, ½” ID CMS tube and fittings, 3/4” ID hose and SS Hose clamps and bushings and adapters to fit it all together