Website Update Log

Committing to a Watermaker

This discussion covers the following topics:


Why (and when) to install a watermaker:  

Since we've managed very comfortably without a watermaker for 8 years of cruising and in many different  venues, it was with some regret that we decided to install one for the Pacific run.  When it came to water, life had been simple.  Now it was going to get complicated.

 One reason for this reluctance is that watermakers are one of the most problem-prone systems on a cruising boat as e.g. validated by successive SSCA Equipment Surveys and much anecdotal commentary out amongst the 'fleet'.  They also are relatively expensive to purchase, demand meaningful amounts of space previously used for other purposes (and let's not forget the filters, chemicals and spares...), demand power (just like the ice in your freezer, RO water comes straight from the battery bank or engine), and also demand time (perhaps the most precious thing when cruising)  to be monitored, serviced and perhaps repaired.  Up to this point, we'd escaped all this and yet always had enough quality water to remain clean & healthy.  No longer...

Does one need a watermaker?  To back up just a bit, here's my suggested 3-Step method for deciding whether & when to install a watermaker on a cruising boat:

Step 1:  Go cruising, first.  Give yourselves some time to adapt to the lifestyle and  learn what your water needs are.  This may also allow you a chance to frame your realistic cruising goals, geographically speaking.  How else will you be able to size the watermaker you may later purchase...or know whether your future cruising will mandate a watermaker?  Remember that RO watermakers are sold all over world.  Some cruisers even think the best watermakers are not readily available in North America but rather in cruising destinations like Europe and Trinidad.  So ease up, allow your cruising lifestyle to emerge, and rest assured that, meanwhile, the cruising you do will take place where the locals drink water.  Instead, and to begin your cruising with high-quality water, consider installing a 1-micron water filter.  The Seagull IV is one typical choice found on cruising boats ( altho' there are several brands to choose from.  (Such a filter does require a pressure water system).

Step 2:  As your cruising begins, fabricate a good rain collection system for your boat to catch rain water.  I would define a “good” system as:  1) it uses the deck (which is large in area, doesn't add windage at anchor, doesn't need to be set up or struck in high winds, and doesn't flap around in the breeze; 2) can be activated from within the boat, perhaps at 3 a.m. when you'd like to remain dry and warm; and 3) filters or screens the water and deposits it in your water tanks with no manual labor on your part.  Depending on where you are cruising, such a system may help you only a bit or a great deal (in most places around the world).  Such a system is usually simple and inexpensive to arrange, takes no power and minimal maintenance, and might allow you to adjust downward the capacity and therefore cost of any watermaker you may later decide you need.

Step 3:  With some real-world experience on your boat with your crew, you can now consider whether a watermaker is A) needed, B) desired or C) unnecessary.  Usually, the answer is B or C. 

How we went from C to A:  We'd followed these steps and kept finding that, for us, the answer was C.  But now our answer had become A and with a bit of B thrown in; how did that happen?  Here are our Pacific cruising-related reasons that led us to install a watermaker:

1.      Crew.  All our cruising had been as a crew of two.  We were now adding a third crew member to help with the passagemaking.  Our 150 gallon water supply had suddenly shrunk by 50% (from 75 gals/person to 50).

2.      Availability.  We were off to visit many small island communities which depend on catching rain water to supply their needs.  In dry periods, these communities may not have water available to share with visitors...or almost as bad, their catchments may be at low levels and so of dubious water quality.  (Next chance you have,  look inside one of those catchments).

3.      Health.  Some Pacific island communities are not disease free.  Taking on water throughout Europe, the Atlantic Islands, or in fact much of the Caribbean gave us no qualms...and no tummy aches (although we do think our 1 micron filter helped in that regard).  From what we could learn of the Pacific, some diseases like hepatitis are widespread and water quality not always at a high level.

4.      Logistics.  No hose bibs and marina docks are in WHOOSH's Pacific future.  We expect the normal method for all provisioning will be via bags & jugs while using a dinghy.  And altho' this reason definitely falls into the B) category, a watermaker will help us avoid jugging water, which in the Pacific Islands can be a fair savings of labor.

Which watermakers did we consider...and why?

First, the basic criteria:  Things started out so logically and simply, you understand.  My first criterion was a 12V system, which means I didn't (but you might) consider an engine-driven system (no room inside the engine box) or an AC unit supported by an installed generator (which WHOOSH lacks).  I also liked the redundancy a 12V system offers as it can continue to make water via alternative 12V sources and/or a small portable generator we carry, even if the main engine is kaput.  So this decision alone quite narrowly focused the rest of our research.

 There were several other approaches we considered.  One was to install an independent, small and engine-driven watermaker platform – for one example, see .  Some folks find this approach sensible as you can take care of battery charging and water making concurrently (provided the small engine stays healthy) but this seemed  to go in all the wrong directions for us:  even more cost and more complexity, more space needed & weight added, less diesel fuel for the main engine and so reduced range, and even more maintenance than a watermaker alone would require.  Like I really needed  another engine... 

 And then there's the approach, no matter how the watermaker is powered, of building one's own system – usually to reduce cost.  Like any other owner-built system, one of the main advantages of this choice is the intimate knowledge the ship's engineer has of the system.  I however wanted an off-the-shelf product in part because of our time constraints vs. the inevitable learning curve I heard about from DIY'ers, and the fact my goal was not to become an expert on RO watermaking, needed to some degree to make all the component decisions, but rather to become an expert on MY watermaker.

 One last (basic) criterion was to opt for a modular system, meaning the main components would be independently mounted and linked together by me (which in truth is a bit of a DIY approach, as well).  Like most smaller cruising boats needing to swallow a watermaker, WHOOSH had no single big space for a fully assembled, frame-mounted  unit.  I also had some reservations about being able to view and/or reach all the frame-mounted  components once servicing and repairs became necessary.

With the basic criteria firmly (I thought) in hand, I quickly worked my way down to 3 choices:

1.      The PUR 160, now manufactured by Katadyn, a Swiss company (  Claimed performance is 6.8 gals/hr at 18 amps (12V DC) or 2.65 amp/hrs per gallon of product water.  Anecdotally, I have heard of many failures of the smaller PUR 40, even right out of the box or in the first year of use.  But among long distance sailors using the PUR 160, I heard of  far fewer failures and it is a very simple system, which means installation is relatively easy.  Checking the SSCA Equipment Survey (on-line with 1500 surveys completed by boat owners in mid-2009), the PUR brand had the largest installed base in that survey and one of the lowest failure rates.  Could this be our choice?  One fly in the ointment is that I couldn't find any PUR owner raving about customer service & support, either over in Europe or back in the USA.  It seemed customers endured warranty and service support from Katadyn rather than praised it.

2.      Village Marine's Little Wonder 200 (, another 12V modular unit.  Claimed performance is 8 gals/hr at 17 amps (12V DC) or 2.1 amp/hrs/ per gallon.  Anecdotally, these units consistently got high praise among cruising sailors both for reliability and dealer support.  I found this e.g. to be the case among Yahoo user groups (e.g. Pacific Puddle Jumpers group of Pacific cruisers) and among SSCA Discussion Board members.  And the SSCA Equipment Survey showed VM units to be the second-largest installed base and with relatively low failure rates.  This choice looked even better...

3.      Spectra Ventura 200T, a modular and slightly bored out but otherwise identical twin to the Spectra Ventura 150 (  Claimed performance is 8.3 gals/hr at 10 amps (12V DC) or 1.2 amp/hrs per gallon – almost twice the efficiency of the other units  This is the only brand available and well supported in the USA (where I was shopping) that offered the Clark Pump, an efficient and non-electrical pump supported by only a 12V Shurflo feed pump.  As long as I'd been hearing about Spectra watermakers – quite a few years now -  the good news seemed to come hand-in-hand with the bad.  A batch of bad pickle chemicals had led to widspread systems failures (but parts were replaced at no cost, quickly, by Spectra), the earlier stainless and then aluminum chambers were failure prone (but are now replaced by a non-corroding composite material), and the sophisticated self-maintenance brain (the MPC 5000) caused failures (which in the field was overcome by Spectra's engineers providing machine language code to owners).  The SSCA Equipment Survey showed Spectra to have the third largest installed base and the highest failure rates of my three candidates – on average one failure per unit every two years.  Clever technology indeed but with a spotty history in the field, Spectra seemed to score well on product support - by dealer, factory personnel and via a unique 'Spectra Reps in the Field' program where experienced cruisers are factory trained and then offer support to and carry spares for other cruisers.  But Spectra seemed to do less well in terms of reliability.

Common Denominators:  All three of these units are modular.  I spoke to dealers for all three brands and was equally impressed.  All three systems will produce less water than claimed in a variety of circumstances, and are unlikely to exceed their ratings at any time.  All three are basically 'manual' in operation and omit automatic features, meaning they must be manually back flushed with fresh water or pickled, their filters visually examined and changed, and the unit generally monitored by a thinking, caring owner.

 Each of these units force certain installation and operational edicts on the owner, so in each case the physical installation was going to take some careful planning.  Since these constraints differ from one unit to the next, reading the on-line installation manuals – carefully – is a big step in picking a unit you'll be happy installing and using.  And the performance of all three of these units will depend on a mix of variables:  the quality of the installation, the location of components relative to the water line, the gauge and length of wiring used, the kind of water in which the unit is operated, how the boat's DC system and battery health is managed, and more.  Perhaps I should repeat:  I learned that reading the owners' manuals before choosing a brand & model was very enlightening.

The missing criterion:  At this point and while still mulling choices, it dawned on me I had been so focused on weighing each brand's details that I'd neglected the key criterion.  Specifically, how much water did my crew need me to make?  And based on that, for each brand how much electricity would need be consumed?  And based on that, how far out of whack was each watermaker going to put my DC energy budget.  And finally, how was I going to replace those additional consumed amps?  I had missed a whopper of a tree while busily analyzing the forest.

 This put a renewed focus on the Spectra product, clearly the most efficient of the group, and made me dig a bit deeper into their reported problems.  What about all those corroded chambers?  Well, that was now ancient product history.  What about the higher failure rates?  After gathering more info, my conclusion is that a sizable portion of the more recent failures have been caused by the Spectra's MPC 5000 'brain'.  Since I would buy the 'Deluxe' model (in Marketing Speak, 'Deluxe' refers to the simple/manual version with no 'brain'), those failures would not be a factor.  Another issue is the lesser pre-filtering that is provided for in the Ventura models as they have only a single 5-micron pre-filter and no second, upstream 20-micron pre-filter.  Poor filtration and lack of filter changes leads to downstream mechanical issues and lower product output. Well, I ultimately have control over what feed water I put through a watermaker and I control the pre-filter maintenance.  And it will always be possible to subsequently add a second pre-filter if I think it's needed.  So the lesser filtraton seemed to be an issue that deserved attention but I could manage.

 When digging for info, I also found a rich digital library of Spectra technical support documents on their  website, something reassuring given I'll no doubt have my own issues while out in the Boonies somewhere.  And the gem in the library was a 'Notes to Cruisers' document (see the list of info sources below) written by Don Wilson (TACKLESS II).  Don is one of those 'field reps' who had helped many Spectra owners in the field and distilled all the failure causes into understandable diagnostic steps and maintenance guidelines.  In the end, I came to the conclusion that the Spectra product – in its simpler form – offered acceptable reliability, excellent support, and made it easier for me to keep my energy budget somewhat in balance.

One decision made:  And so a basic plan for managing water aboard WHOOSH on her Pacific run had been formed.  I would  install a Spectra unit, use a tow generator's excess energy while on passage to fill the water tanks and keep the battery bank up, arrive at the next island with full tanks & bank, live off the stored water while replacing the daily DC load with our wind gen and Honda generator, and then depart on the next leg with plans to refill tanks and bank.  If the Spectra performs close to its claims, my (hypothetical) numbers work.  It will be interesting to see what we experience out in the real world.

Installing a Watermaker:

First, let it be said that nothing apparently generates more creativity among boat owners than a modular watermaker that needs installing.  I've seen installations that would make a Swiss watchmaker proud.  For others, I've had to walk bow to stern to witness the various pieces.  Carpets are rolled up and cushions pulled away to reveal a wide array of components.  And some units hang upside down, seemingly defying gravity like bats in a cave.  The more installations one sees, the more options one gets to choose from when installing one's own unit.

Second, boats like WHOOSH which have been cruising for a while have a further challenge.  Buy a new boat and you might have several choices on where to place the watermaker's components.  There might even be room for a frame (non-modular) unit.  Cruise a boat for some years – a place for everything and every place filled – and you've got some spatial challenges on your hands, not to mention a really fun install .  This is further magnified if living aboard at the time.  For WHOOSH, our motto became:  Relocate existing 'things' to make room for watermaker 'things'.  Said differently, there was a Ripple Effect that expanded the work to be done beyond installing the watermaker.

Third, don't overlook the fact that a self-contained or 'frame' model will take far fewer man hours to install than a modular unit yet cost very little more.  Just be sure to consider how accessible the individual components of a frame model will be, which in turn will depend on the location of your  installation.  Modular may also be more expensive in the sense that one will need runs of hose, hose clamps, and perhaps fashioning small mounting platforms for some of the modules.  In my specific case, with a modular install behind me, I would look extra hard next time at whether a frame modl could be made to work.

Fourth, and as noted above, the unit you choose will dictate much of how & where the unit will be installed.  Depending on the brand chosen, some components must be installed below the waterline, other components not more than X feet above the waterline, while still others must become part of the same temporary loop for flushing with beware installing them at opposite ends of the boat.  The pumps and pressure vessels have enough mass that they need to be robustly something already there or something you add.  You can 'T' the discharge feed water into an existing thru-hull but it's universally recommended that you be able to observe the discharge flow, as it is one way to monitor system performance.  It's also uniformly recommended not to 'T' the inlet feed water, which of course means a dedicated thru-hull & valve - somewhere.  Another uniform requirement is that the inlet thru-hull needs to be of the scoop type.  You might need to leave room above the pump motor for an oil change, or insure things under the pre-filters won't be damaged by salt water when you change filters, and please don't forget the eventual challenge of removing and replacing the membrane or its seals when this is required.  Be sure to keep the wire runs short, avoid elbows and kinks in the hoses, and keep your shorts from getting in a twist.  There is no shortage of guidelines and constraints.

Less is more:  Since ours is an installation done by a Rookie, I'll offer just a few specific comments on it.  You will probably find them related mostly to the Spectra product and perhaps our boat's layout.

Pleasing Discoveries:  There were some pleasing discoveries about installing the Spectra unit.  The only wiring required is a single pair of wires from the Feed Pump that only need to carry 10 amps, about 4 wire gauge sizes smaller (for a 3% loss) than what the other two modular systems would have required.  West Marine puts that in perspective by noting that going down in wire gauge by 2  (e.g. from 12 to 10 gauge) means the amount of copper in the wire goes up by 59%.   A smaller wire gauge (for no more line loss) means an easier wire run.

 Another nice change is that Spectra now has installed an on/off switch on the Feed Pump module.  This makes doing fresh water back-flushing and also pickling easier as one can control the pump right at the module (vs. needing to throw a breaker on a remote DC panel).  A third was that the Clark Pump, the heavy and big component in the system, was compact and appears well protected from transmitting vibration, making it easier to mount than expected.  And a fourth is that our unit came with an array of hose connectors, feed & product water hose, a distribution valve and hose clamps – almost everything we needed for the install other than electrical wire.

 I'll include some annotated pictures that will help to explain the comments below. 

Where to put the Clark Pump?  Put the Clark Pump Where?I ended up choosing a mostly unused corner of our port sail locker, using the thru-bolted isolation transformer plus some wood cleats glassed & screwed into place for the pump's support.  A 'shower curtain' will shield the transformer should any leaks develop in the pump's seals.  Water escaping the Pre-Filter canister when we change filters drains directly to the bilge and room has been left for a second 20 micron pre-filter if I find one is needed.

The 'Before' pic of the port sail locker where I'd hoped to install the Clark Pump

The 'After' pic with Clark Pump thru-bolted to platform but with canister not yet mounted nor hoses run. A Sunbrella 'shower curtain' snaps onto the platform base to shield the Isolation Transformer from any drips


Where to put the Feed Pump module?  Like many Pearson 424 owners, we had previously cut a hole in the outboard shower stall wall and installed a watertight locker door behind which we stow various bulky items.  This area drains directly to the bilge and the DC panel and WHOOSH's main -12V bus are quite near-by, so our wire run could be short.  This was the third place I mounted this module, which no doubt is a comment about me but also about the value of having the real hardware in hand.  Absent leaks in the hose connections, the charcoal filter on this module only needs changing once every 6 months and the area will only see fresh water drained from the filter canister.


Shower stall with outboard locker shown, soon destined to be the home for...

...the Feed Pump & fresh water flush module (where the only wire connections are made). This is also one point where pickling hose is attached, the other being at the Clark Pump.

Locker Outboard of the Sink in the HeadThis busy picture shows several things; let's take them one at a time.  The large Y valve (blue handle) is part of a deck collection system that was previously installed and connects the top of the Y valve to a deck drain. The large black (vertical) hose leads from the Y valve, overboard, to the thru-hull.  The white (curved) hose leads from the Y valve to the (white) collection box (a Rule off-the-shelf 'shower sump') when collecting rain water off the side deck.  A horizontal vinyl tube can be seen in the background, running forward (to the left) from the collection box and toward the tank fills.  Because this system was already installed, I just piggy-backed the distribution of the watermakerf's product water to it.  The watermaker's grey distribution Y valve can just be seen in the upper right corner of the open locker; it receives product water from the Clark Pump via an output measuring gauge.  When 'good' water is being made, the short, curved (and thin) black tube dumps product water from the grey distribution valve into the Rule collection box (and subsequently, the water tanks).  A second black tube, longer and normally just coiled inside the locker, runs from the distribution valve into the sink drain or into a glass, where testing and tasting can be done.  This would be put in place before the watermaker is turned on.  (It can also reach into the shower for bucket filling, if needed)


Where to put that (Damn!) new thru-hull?  No doubt like everyone else who didn't have a dedicated thru-hull available, I fussed and mulled and generally was in denial for some time about adding (yet another!) thru-hull.  In the end, I'm sure it was the right choice for WHOOSH and the new scoop thru-hull insures good flow when underway or anchored in a current.  (Manufacturers are quick to point out a mushroom-style thru-hull tends to create a small competing vacuum in the line as water flows across its mouth, and in fact not using a scoop-type thru-hull voids some warranties).

 Is that dedicated  thru-hull all the manufacturers recommend really necessary?  For a moment, let's take the case of my buddy (and website host) John Stevenson, who wants to avoid another thru-hull. In John's case, he has a seawater manifold serving several systems that in turn is supplied  by a 1.5” ID thru-hull and valve.  He's done the numbers (quantity of water needed for the systems concurrently drawing on that manifold) and figures there's sufficient additional supply for a watermaker.  But let's broaden this to fit most boats and assume there is a thru-hull with sufficient 'unused capacity':  This was in fact true for WHOOSH, too.  Why add a new thru-hull?

Perhaps the acceptable answer is not to.  Here are some things I considered when making that decision:

  • Does the manufacturer mandate a dedicated thru-hull for warranty claims?  And if so, is that important to you if your unit's performance is not up to spec? If that's not an issue for you (e.g. if like me you are over the horizon during the warranty period) and can, with hand on heart, say the feed water supply could not be even remotely a part of the problem, then you may conclude the 'warranty compliance' side of things doesn't matter.
  • By definition, if you are considering using an already in-use thru-hull, then it's external location on the hull is predetermined and you need to consider whether it's in a 'good' location as defined by the watermaker's needs.  Might a sink discharge thru-hull (galley, guest cabin or head)  contaminate the pre-filter – and if so, how often, how much and with what?  What else is on that side of the keel and near this thru-hull?  Some of us, at one time or another while underwater, have seen  food scraps or dishwater exit a thru-hull and we've seen how the 'bloom' associated with that discharge surrounds that area of the hull.  You would want to avoid that kind of contamination.
  • Relying on an existing thru-hull also predetermines the kind of access you have to it inside the boat.  Keeping an eye on the sea water strainer, the first component in the watermaker's feed water circuit, is important, so you want to consider whether a new strainer will a) permit relatively easy visual inspection, b) be easily reached with two hands so the bowl can be unscrewed and screen removed for cleaning without losing the gasket, and c) having the salt water spill from the bowl isn't a problem for that location.  Helpfully, the strainer can be located some distance from the 'borrowed' thru-hull.
  • Consider the geometry of the plumbing required by building your 'T', as the 'T' itself, any necessary reducers, an 'easy' bend of the feed water hose from the 'T' and on both sides of the strainer can collectively take up a fair bit of space if co-located together.
  • Finally, another common manufacturers' theme is to get the thru-hull deep enough that a heeled hull and a fair bit of seaway won't interrupt the solid supply of feed water to the system.  To some extent, this can be mitigated by adding a small 'booster pump' downstream of the strainer, and in fact one system recommends this if the heeled thru-hull isn't at least a minimum distance below the waterline.

In my case, I only had two potential thru-hull candidates to 'T' off of - my two cockpit scupper drain lines.  They failed to satisfy me on almost all of the above criteria, so a new thru-hull became one of our compromises when adding this system.  The offsetting benefit is that at least it is located about as ideally as possible.

The installation was not all sweetness and light:  While Spectra's Ventura 'kit' was very complete, it included a few small items that were either improperly built or metric threaded.  Our dealer resolved these minor issues but this underscores the importance of inventorying (and even 'inspecting') all the components when you first receive them.  The “installation manual” (more 'pages of pictures' than detailed installation instructions) offers less  than I think is sufficient for the novice self-installer but, again, the dealer was both experienced and helpful.  (By the way, our Spectra dealer is Peterson Marine in Oldsmar, FL – ).  It's also fair to say the manual has not been kept current with the development of the product and had some inaccuracies...but dealers of the other brands we considered confessed to this same issue.  (For systems like these, a mix of electrical and hydraulic sub-systems, it's surprising that documentation is not more emphasized by the manufacturers).  In short, one shouldn't discount the value of a helpful, accessible dealer if installing one of these units. 

 Bilge gremlin doing one of the hose runs...And then there's the inevitable trial-and-error process, once the hardware is in hand, of (re)deciding where things should go and  pulling the hose and wire.  (If you see the joke in “It only takes two screws, so how hard can it be?”, you'll know what I'm referring to when mentioning hose runs and wire pulls).  Overall this turned out to be a much more time consuming installation that I was expecting for multiple reasons, but despite rather than because of the product chosen.  The Ventura model is fairly simple to install, in my view.

 Other nits that were discovered during installation:  In my case, the Spectra's fresh water flush canister (where the activated carbon filter scrubs any chlorine held in the tank water) had a 1/2” fitting, whereas all the other fittings and all the hose supplied was 5/8”.  I suspect this was yet another error by Spectra in putting the kit together and the fitting was cemented into the canister so I had to live with it or suffer another delay.   My point is to note all the connector dimensions in case you need more/different hose.  I also “discovered” that, if installing a modular unit in different parts of the boat, as I did on WHOOSH, you simplify the install when locating as much as you can on the same side of the boat.  This will minimize having to cross hose runs over one side to the other, which in some boats can be problematic.  In our case, we had a 'win' with the strainer and feed pump being only feet away from one another and on the starboard side, but had to cross three other hoses from one side to the other.  This just means more work and more hose, and was not the end of the world.  BUT don't overlook that you may need additional 1/4” high-pressure hose and that's not available at a typical West Marine or local chandler.  Again, the dealer solved the puzzle.  A final grumble:  Doing this install while living aboard and out on the cruising trail – meaning with a full and fully commissioned boat -  does add to the challenge.  Don't underestimate the benefits of installing a frame model, if your boat can swallow it and allow you to still reach/service the components reasonably.

So where does the product water go?  Ultimately one is rewarded with potable water, so now what?  Usually, a distribution valve of some kind – a 'Y' valve – is recommended so that initial product water, still salty, can be discarded and the 'good' stuff tested before the valve is thrown and distribution to the tank(s) can begin.  (I saw PUR literature that told the user to only collect product water in jugs and then decant the jugs into a tank via the deck fill after testing each jug's water, as this way salty product water – e.g. if the system had failed while being operated – can never contaminate the potable water in the tank.  Tho' good insurance, this doesn't sound too suitable for folks out sailing).  Before finalizing your distribution arrangement, here are some things to consider:

  1. The initial product water needs to be easily discarded.  For this reason the distribution valve is often near a sink, where product water is channeled from the valve to a nearby spigot or where  tubing from the valve itself is used .
  2. Product water may need to go to more than one tank, which means a manifold is needed downstream of the distribution valve.  Your boat's tank locations and height swill need to be considered when designing how to distribute the product water.  And I'm also reminded to mention that a preferred way to deposit the product water into the tank is by 'T'ing into the fill hose (not the vent hose) or by tapping directly into the top of the tank.
  3. While this doesn't relate specifically to the distribution of product water, it's worth noting that a system not in use for a period will need biocide to be suffused within the membrane to prevent growth of biologics - the “pickling” everyone hears about  This will in turn require a closed loop that feeds a biocide solution to the membrane and back to the biocide source (e.g. a bucket) for some number of minutes.  If one has a big sink or the shower stall nearby, a biocide/product water mix can be easily prepared and distributed without worries about spills.

Considering the above, it's not surprising that many watermaker distribution valves end up in the head (where there is both a sink and a shower stall) or the galley area.  We chose the head.  Our product water is either sent via a short run of tubing to the sink (or by adding additional tubing, down to the shower stall pan) or, throwing the distribution valve the other way, is distributed into a sealed pan (a Rule product originally intended to serve as a shower sump).  From there, the feed water is sent forward to a 'manifold' (just another 'Y' valve) in the forward cabin and finally diverted to either the bow or starboard tank. 

 It's probably a good idea to keep distribution of product water to one tank isolated from the other tank (vs. using a a shared 'Y' fitting with no valve).  If the unit begins to fail during operation, the water in only one tank will be contaminated.

Further research:

Because there are so many variables involved in the installation and performance of a watermaker, the cost and effort are both significant, and the results (water) so important, choosing a watermaker deserves a fair bit of research.  (There's also abundant 'urban legend' re: watermakers, further necessitating fact over hearsay).  In that regard, what follows are a few on-line sources that I thought were helpful.  Just keep in mind that most products evolve – in design, construction and documentation – and the following references are all historical, meaning things have most likely changed between the time these were written and when you are reading them.

This is a collection of watermaker-related articles by some individual cruising folks, including Nigel Calder, and is offered by the Hydrovane dealer who carries the Trinidad-built EchoTec watermaker brand.  After the inevitable pitch for the rationale that EchoTec's units operate by, you'll find the write-ups.  I especially appreciated the first and the last write-ups.  The first, written by Nigel, points to the fact that even 'systems experts' can make some bad (as in 'human') choices in how a watermaker is installed, as well as how the boat is operated when a watermaker is aboard.  The moral of the story is not to underestimate the possibility of a 'calamity'.  In Nigel's case, it was ending up mid-ocean with a watermaker, two water tanks, and no water.  The second (last) article I appreciated not because of the author's “final” conclusion (his latest watermaker is only 6 months old and still on its Honeymoon) but because it chronicles the realities and the history of watermakers on cruising boats.  It rarely has been an unblemished and happy story.

This is a summary of observations and advice by a cruising sailor, Don Wilson of TACKLESS II, who was trained at the Spectra factory so he could also serve as an 'in the field' Spectra service rep.   While it is oriented to the Spectra product line, there is a lot of 'real world' information in Don's article that I think any cruising watermaker user would benefit by reading.  And isn't it noteworthy how often the problems boil down to the basics:  clean feed water, good filter maintenance, a healthy DC voltage at the watermaker, the right operational practices, and paying attention to the details (good installation, addressing drips and such).

The first link is the front door to the Seven Seas Cruising Association.  I offer it here because, if you are a member, you can log in and go directly to the SSCA Equipment Survey where there is a wealth of detail about the systems cruising sailors choose for their boats and anecdotal comments on what has worked, tricks that have been learned, and so forth.  This can be very instructive reading and may be worth the cost of membership ($50/year for a crew) all by itself.

 The second link is to the SSCA Discussion Board.  There are a number of such 'bulletin boards' on the Web and everyone seems to have one or two favorites.  I recommend using this one when soliciting opinions and practices for three reasons:  the experience of the membership is, in some cases, very deep; the data base of prior discussion threads, easily searched, can provide immediate information you may be seeking; and the tone of the DB's discussions is almost always civil and constructive.


The Marriage vs. the Honeymoon:

We have only begun to live with our Spectra unit, so allow us to experience it for a while and we'll put our further impressions on both the “honeymoon and also the marriage” here.

Update as of April, 2010:  We've been using and living with this watermaker for a few months now and already I realize there are some additional thoughts worth adding, so let's consider comments on the marriage's first year.

Feed Pump Installation:  The sound isolation pads on the Clark Pump are excellent, yet the unit itself  generates little vibration or noise. The feedpump, on the other hand, is buzzy noisy and if placed near an area on the boat you are going to occupy (and what part isn't?), it needs to be sound isolated.  I used some of the same rubber material that I use to isolate the wind generator pole from the mizzen mast where they are bolted together, and this has helped considerably.  I recommend you do NOT just screw the Feed Pump to the mounting surface as I originally did.

One vs. Two Pre-Filters?  This unit as provided by Spectra came with only a single pre-filter body and 5 micron filters.  Since buying it, I've been sternly warned by some (experienced, long-term) Spectra owners that the unit should have two pre-filters, a 20 micron unit ahead of the 5 micron unit like most of the rest of the Spectra line.  I've also met cruising folks (and pleased Spectra users) who have been using their units with only the single 5 micron pre-filter.  If there's no 'right' answer, what might be the 'better' answer, I've wondered?  I notice Don Wilson, in his excellent "Operator's Notes for Cruisers" mentioned earlier, highly recommends two pre-filters for the two feed pump systems because the high volume of water (about 150 gals/hr of feed water) is simply asking an awful lot of one pre-filter.  Extending the logic – and recognizing that I've already made water while anchored in Panamanian water I wasn't thrilled about using – that seemed to suggest to me that two pre-filters would, to some degree, add protection to the Clark Pump that otherwise wouldn't exist.  On arriving in Colon, Panama I added the second pre-filter housing.  It's been interesting to note that the 20 micron filter is collecting noticeably less 'crud' than the 5 micron filter.  This has tempered my view that two pre-filters are 'essential'.  I think the more important issues are whether one has the tankage (and cruising plans) to restrict watermaking to really clean water (e.g. when at sea) and how diligent one is at replacing filters.

'Real World' Water Production:  As noted earlier, I sprung for the 200T Deluxe unit (over the 150), willingly paying a bit more money and one more amp of DC to obtain two more gals/hr.  This seemed like a great trade-off and, to refresh you on the specs, I'm supposed to be seeing 8.3 gals/hr at a water temp of 75º F.  I assume this initial experience we're having is going to be our 'best case' for this system, as we've been running it in 80-85º F water, the system is all new, and we've limited watermaking to times when the batteries have been on charge (and so usually at 13V+).  I'm usually seeing 9 gals/hr as meaured on the little gauge, but I recently measured actual output (with a scummy 5 micron and clean 20 micron filters) of 8.2 gals/hr for the above operating conditions.  So my unit is performing close to spec and the gauge appears to be optimistic by ~ 1 gal/hr.

'Real World' Electrical Use:  Again, the 200T specs promised electrical consumption of 10 amps DC at a (generically labeled) "12V".  I have at times run the unit when the batteries are not in charge but with battery voltage relatively high (12.4 – 12.6) and I have never seen 10A DC, usually seeing 9.5 or so.  I'm confident the Link 2000R I'm measuring this with is accurate, so perhaps this is an example of a new system showing optimum performance.  It is certainly energy efficient.

Where to Put the Pieces, Chapter 2:  I have both my pre-filter cartridges in one of the sail lockers.  In many ways, this works nicely.  But are your sail lockers like mine?  (Think 'long distance cruising boat...).  Changing the pre-filters is easily done once I can slip into the locker, but emptying the forward section of the locker is a bit of a hassle, not easily done at sea and probably retards my intent to change filters.  I'm just saying...

Water Consumption: We wondered just how much, if at all, our rate of water consumption would increase once we had a watermaker. On the one hand, we've done a decade of cruising on two boats without we now consume water thoughtfully and our habits are well ingrained. But we also hear from everyone who's made this transition that their consumption rate has increased, sometimes spectacularly. Obviously, some increased consumption is inevitable as some old habits exist within a new context. E.g. when offshore and in secluded anchorages (without knowledge of when we'd next refill our tanks), we would rinse our dishes off with salt water, then wash them with hot soapy salt water, and then spritz them with fresh from a squirt bottle, to spray off the salt before setting them to drain and be dried. We first learned to do this when cruising in the Bahamas and it noticeably reduces how long a tank of water lasts. However, now the washing part of this seems an unnecessary time-consuming step.  Instead, we prefer to save the propane, rinse off everything using salt water and do the washing with fresh. But the big surprise for us has been how much more water it seems necessary to use when showering, as the watermaker's water is very soft and removing soap from one's body just inevitably requires more rinsing.  Bottom line for us:  We used to see, on average and without the salt water dish washing regimen, a usage level of about 7 gals/day. Now it turns out to be about 10 gals/day.  So far...

As you might know, a marriage's first year is not without its trials...and I've had a few laughs at my own expense, as well, flooding a locker because I set a valve incorrectly and over-filling a tank, which also back-flooded that same locker.  But in general, it's been an easy 'first year' – so far.



© Jack Tyler – April, 2010
WHOOSH, departing Las Perlas Is. for the Galapagos