We’re in Hot Water!

When we first took over Galapagos, Melissa and I felt as if we had just bought the Queen Mary. Stepping up from our sweet Cal 34, Moonrise to big ‘ol Galapagos was intimidating and exciting all at once. To paraphrase Bernadette Peters in The Jerk, It isn’t just about the waterline, its all the stuff.

[embedyt] https://www.youtube.com/watch?v=Jfug0oN1Jt8[/embedyt]

Of all the stuff that came with Galapagos, nothing could seem as luxurious as a hot water heater. Hot water from the tap? Just like home? What a time to be alive!

It wasn’t hard to slide into such decadence and when I began to re-plumb the whole boat with PEX tubing and new faucets, I knew that I wanted to update the old water heater and get it out of the engine room. So in January of 2017 after much perseverating, measuring and no doubt boring Melissa to tears with technical minutia, I bought an IsoTemp SPA 15 Marine water heater.

For the uninitiated, marine water heaters have an electric heating element, just like the units you have at home. But they also have a small heat exchanger that connects to the cooling system on the boat’s engine. That means you can have hot water just by running the engine for half an hour. The SPA 15 is tiny, only 4 gallons, but that is more than enough for Melissa and I to enjoy showers, wash dishes, and do all the usual domestic chores that can make living aboard a sailboat seem almost normal.

The main reason I chose this particular water heater was that it could fit, just, beneath the sole of the aft cabin. Getting the water heater off a shelf in the engine room not only freed up space for storage there, it placed a fairly heavy container down low, where heavy things should be on a boat.  This allowed me to secure it in place; confident that it would stay there in the event of rough weather or, heaven forfend, a rollover. It also simplifies the design and use of the the engine’s cooling system with the heat exchanger since no external header tank for coolant is required.



This area beneath the aft cabin sole made sense as the center of our water system. There was room to locate the water heater, water pump and a simple manifold for the hot and cold water. The PEX tubing and fittings have proven to be quite reliable and really easy to use and modify.

For almost two years we have enjoyed what would have been an unheard of luxury when we first started sailing. In fact we may have grown a little complacent about having hot water and I suspect that Galapagos, like most boats, can sense when her owners are taking her, and her stuff, for granted.

In hindsight I shouldn’t have been too surprised when one night, lying in my bunk, I heard the water pump come on for half a second. Three minutes later, the pump bumped on again. Checking the faucets on the boat yielded nothing. Finally, pulling up the sole in our aft cabin, I could see a small trickle of water. Just an innocent little trickle. It could be anything. A loose PEX fitting, probably. In two years of cruising with lots of bumpy weather, things are bound to jar loose. I would have this fixed in no time I thought.

Sadly, all the easy things were ruled out and I could now see that the water was coming from under the water heater. If I wanted to learn anything more or have any hope of fixing this leak I would have to remove the tank from my super snug location under the cabin sole. I began to question the wisdom of locating the water heater there and was dreading the process of disassembling the bracing and fittings.

But bitching and moaning wasn’t going to stop the leak. And if I didn’t stop the leak we would lose precious water and,  quelle horreur!, Melissa wouldn’t be able to have a hot shower. That was a future too smelly to contemplate for long. Onto my belly I slithered and an hour or so later, I had the tank out. It got a lot easier after I had reinstalled and removed the tank a few times as I tried and failed to understand where the water was actually coming from.

IMG 3575

The water tank removed and in the shop. In trying to locate the leak, I had thought something obvious might reveal itself without too much effort. I filled the tank with water and looked for air bubbles. No such luck.



This is the heating element and the associated controls that I removed while trying to locate the leak. The electric heater element is mounted through a plate that has a rubber gasket that acts as a seal on the tank. In conferring with the manufacturer, the gasket was mentioned as a point of failure and replacement gaskets are sold on the IsoTemp site.

After disassembling the tank’s electrics and eliminating the rubber gasket, a failure point suggested by the manufacturer, I had nothing left but the stainless steel tank itself. As you can see in the photos, the SPA tanks are encased in a hard plastic case with a foam insulation. Since I really had nothing to lose, I carefully cut the outer plastic casing and started cutting away the foam insulation so that I could see the steel tank.

IMG 3587

Here you can see that I am well and truly committed to finding this leak. By removing a hard plastic band from the middle of the tank, I could remove the bottom half of the cover. I then had to cut away the foam insulation that covered the steel tank. At the bottom, you can see the pin hole leak.

But even with the steel exposed and the tank full of water, I couldn’t find the leak. No, the tank had to be under pressure. Fortunately I was able to pressurize the tank without having to put it back under the sole by using some spare PEX tubing, fittings and a hose bib in the engine room. Voila! the leak finally revealed itself. I had suspected that the weld had somehow failed but as the photos show, the pinhole leak is actually a little above the weld. It is troubling that the tank failed after almost exactly two years and we are wondering if another leak will develop at some point in the future.



In researching how best to repair the tank, a few of options were presented. Some people have had good luck with JB Weld and if we were far away from services, we would have taken the epoxy repair approach. Melissa has never seen a problem that couldn’t be solved with epoxy and was ready to go that route.

But since we were only a short dinghy ride and walk from several welders, I thought it might be a more durable repair to just have the pinhole spot welded. Walking down the streets of La Paz, carrying my leaky, disassembled water heater, I knew that I had arrived as a cruiser. I also felt a bit like a local; no self respecting Mexican would throw away a perfectly good water heater just because it had a leak. Everything can be repaired and made useful again.

A short walk from Marina de la Paz I approached the men at Taller de Soladura el Chicote (Chicote’s Welding shop) and pointed to my little leak. One of the men took my tank and soon a few other guys were gathered round including a very old man that did not do or say much but seemed to have some position of authority in the business. Was he the elder Chicote? One of the guys did a bit of grinding, selected a welding rod and took my tank over to the welding station. The welding machine ran for all of five seconds and my pinhole leak was no more. Total cost: 150 pesos. About 7.50 USD. The shop seemed pretty busy but I think my job was so small they just took care of it while I waited. It took all of ten minutes and I was schlepping my tank back down to the dinghy.


The guys at Taller de Soladura el Chicote look over the tank. It was a quick, easy repair for them.

Once back on the boat, I filled the tank and put it under pressure again to see that the weld was holding. Huzzah! No leak.  I reassembled the plastic case as best I could and sprayed expanding foam inside to provide a bit of insulation and to give the bracing and mounting hardware something to work against. It was a glorious site seeing the tank installed and holding water pressure. Let’s hope we get many more hot showers out of this tank.

A phrase that seems to pop up in our conversations chez Galapagos is “In for a penny, in for a pound”. There were moments in this project that made me question how much further down the rabbit hole I really wanted to go. Many of our adventures keeping our boat in good repair seem to involve a decision to push on, despite the evidence that we are in over our heads. But one of the luxuries of this lifestyle is an abundance of time. Time to read, enjoy the beauty of the world around us and time to expend ridiculous efforts where normal people would have just pulled out a credit card and bought a new water heater.

Once again, Melissa and I have proven to be abnormal.  What’s the most ridiculous repair you’ve done on your boat?


14 thoughts on “We’re in Hot Water!

    • This water heater does not have an anode. Perhaps that could be a factor. But while galvanic corrosion can occur anywhere, typically being hooked up to shore power is seen as a culprit. We haven’t had shore power since February of last year but we did bring a portable generator onto the boat and I wonder if running that could cause stray current to develop a pathway for corrosion.

  1. Hmmmm, most ridiculous repair….so many to choose from. Like buying a $6 toilet seat from Home Depot to pillage the hinges because of course ours crumbled to dust and the seat was a weird size and we couldn’t find a replacement. Or having to repair a waterline because that leak in the bilge was caused by mounting a floor plate to a stringer and drilling the hole in the stringer punctured the water line that was running inside the stringer. Or working hours to clear the mud and seashells from our air conditioner line because a “hired” captain ran us through the mud at low tide. I could go on; just know that you are not alone. And hanging with other boaters I am sure you are well aware of that.

    Congrats on the cheap fix. Sometimes you win one.

    • Thanks for putting things in perspective Marie. Those are all great examples of how dumb some of the projects on a boat can be. I bet drilling a hole at your waterline was an event to remember.

      • Hahaha, my hubby actually pierced a pex water line. inside the stringer that was about 14″ deep. If he “tried” to find it he wouldn’t have. It was such a freak thing. And it took months to figure out where that slow steady leak was coming from.

        Enjoy the day!

        • Glad you clarified that I misread waterline to mean at the waterline. Great stuff that PEX tubing though. Even that little booboo could be fixed without too much trouble.

  2. I was intensely frustrated just reading this, I can’t imagine how frustrating it must’ve been to experience it. I can only hope it was stray current corrosion because the alternative would mean some incredibly poor quality control during production. Of course, now you’ve got to worry about that…

    As for my most ridiculous repair, it had to be when I was investigating the cause of some rich engine smoke, which had been a problem since I’d bought the boat but the engine was due for a turbo rebuild so I chalked it up to that. It got a lot better after the turbo service and injector cleaning but was still there at high RPM. Shortly thereafter, I went on a “let’s quiet the salon” mission and sealed up all the floorboard seams, old component holes, and the like that communicated with the engine compartment. It definitely got quieter but suddenly the smoke was a lot worse. A clue! There were several bulkheads between the engine compartment and the fresh air intakes on the transom and it turned out that the opening in the last one was too small, by far. Several strategically placed 3″ holes later and the problem was solved.

    • Dearest Mr. Pook,
      In my correspondence with isotemp, they expressed surprise at the way this tank failed. Usually the gasket will fail and that is a replaceable part that you can buy (in the states or Canada)

      So the matter of galvanic corrosion seems to be a real option. Also if it was a manufacturing defect, the odds would be in favor of the leak manifesting a bit sooner than years after installation.

      We did use the electric side of the water heater at the dock back in 2017 when we were living aboard for six months prior to our departure but since then I think we have only been plugged into shore power for a few weeks in Ensenada and a week in La Paz. Without the AC circuit on, the tank is really pretty isolated from the usual sources of stray current. It is attached to the engine via the cooling water system. But if that was a source of stray current I would think we would have seen a failure in the heat exchanger inside the tank. I suppose the water lines themselves could also act as conductors of current. More research is needed.

      As I mentioned in another comment we did bring a small generator on board and I wonder if we could have caused a problem by using that to run the hot water heater. I’ve only done that a few times but it was really nice to have hot water without running the engine.

      I have yet to hook the water heater back into the boat’s AC system out of concern for this being the cause of our leak. Another topic of research.

  3. Tis the season for hot water heater repairs!

    We recently returned to the boat to find coolant fluid under the engine. The overflow tank was full, more so than usual. I stood in the engine room scratching my head for a minute. How did I get more fluid in the tank? How did it flow uphill from the engine? We had been away from the boat for a week and nothing had been running. So how did this happen. It dawned on me that the heat exchanger had a small leak. The freshwater system stayed pressurized even with the pump off. This forced water into the heat exchanger’s coolant tubes, up through the engine and into the overflow tank.

    The joys of boat ownership!

    I have often said, if you do not enjoy repairing boats, and I really mean enjoy it, this is not the lifestyle to choose.

    Mark and Cindy – sv Cream Puff

    • Mark, I wondered about that scenario as well as my response to Saffy the Pooks comment will confirm. I am concerned that I don’t fully understand the root cause of this failure.

      In your case, perhaps the cooling water between the engine and the heat exchanger in the hot water heater could act as a conductor and allow for galvanic corrosion to occur. Or perhaps it was just an old water heater.

      And your comment about having to really enjoy working on boats is spot on. Melissa and I find ourselves carefully downplaying many of the positive aspects of our lifestyle simply because we don’t want to encourage people that can’t really understand what is entailed. Even inveterate do it yourselfers such as you or me can get really tired of living and working inside a machine as complex as a sailboat.

  4. Wow, Mike…

    That is certainly not something one expects from such a good quality water heater… [I’m softly knocking on wood as our Isotemp has been trouble-free so far…]

    Great job fixing it.

    Do you have any further insights re: manufacturing defect or galvanic corrosion? These are supposed to be immune to galvanic issues since the AC heating element is purported to be electrically isolated from the rest of the tank. [One reason why theory don’t use anodes…] I wonder if that dielectric isolation was compromised?

    May it provide trouble-free service for another 30 years or so…

    Cheers! Bill

    • Bill,
      I do not really know what caused this pinhole to develop, more or less spontaneously, almost two years after installation. The leak was near the weld bead but not on it but I suppose a moment’s inattention could have allowed the welder to drift over and touch the tank there, weakening it. Galvanic corrosion is so insidious that it is always an option. One troubling theory is that our new portable generator could somehow contributed to accelerating corrosion. The AC system of the boat had not been attached to shower power for some months but I had used the generator on the boat and it would happily run the water heater (it is only a 600 watt element). In any event, I have not connected the hotwater heater to our AC system since reinstalling the unit back in January. I make enough hot water in the morning with our kettle to make coffee and attend to our ablutions. Generally we are more interested in cooling off in the shower than getting warm.

  5. As to the most rediculous repair…

    Last summer at anchor one sunny afternoon our 12V DC power shut down.

    Everything off. No smoke. No smell. No alarms. And no appreciable load [just the usual stuff averaging ~12 amps…]

    It was as though the 350 amp primary feed fuse at the batteries blew [which was my first thought…]

    I decided to do some tracing and grabbed a VOM to test for voltage on the [few] 4/0 positive cable connections from the battery bank.

    Hmmm… the alternator on the engine still has 12 volts…

    We have an emergency 12 volt power disconnect switch, so I continued there [after first confirming it had not been accidentally switched off…]

    Hmmm. No voltage on the output side of the switch, but 12.7 volts on the input [battery] side of the switch… [Yup, the switch was cool to the touch…]


    I toggled the switch off and on a few time with no success. Aparently the switch just died, and with just a small 12V DC load… i.e., No surge of current running a welder off the inverter [I exaggerate…]

    Having no spare switch onboard, I ended up just bypassing the switch to put us back online [and it has since been replaced…]

    This seemed rediculous because one never expects a high amperage switch that has maybe been cycled a handful of times in its life to catastrophically fail out of the blue— especially with no appreciable electrical load on it…

    On the plus side, that is the right way to fail… [vs. being unable to kill power in an emergency…]

    What happened?

    After I removed the switch, I noticed one of the 3/8″ cable connection studs on the back was loose; the other wasn’t. I suspect a connection [solder/weld?] just suddenly yielded, unceremoniously breaking the circuit.

    Perhaps the 4/0 cables hanging on it induced a strain that over time broke the bolt’s connection to the switch?

    But— remember our story started out that it was a warm and sunny afternoon… so it wasn’t all bad… [Aren’t events like this supposed to happen when it it is pitch black and stormy, and you have only been asleep for an hour after a long day…?]

    I haven’t published this one yet, but Donna included more details in a recent blog post if you want more specifics…

    Cheers! Bill

    • Bill, you are the second person to recently tell me of such a switch failing. The fact that you assumed nothing and tested from end to end tells me a lot about you. I replaced all the A B Both switches on the boat with the Blue Sea switches when I bought Galapagos. I think your theory of the strain induced by heavy cables is a good one. And if you are like me, you really lay the torque on those nuts and studs. That is one place where you do not want arcing.

Leave a Reply

Your email address will not be published.