A Review of Using the Katadyn 40E Watermaker for One Season Cruising the Caribbean

I wrote a post about desalination systems for small cruising sailboats in 2015 while I was planning my return to the Caribbean.  I looked at how the systems worked and which kinds would best suit a small sailboat like mine.  I eventually settled on the Katadyn 40E and installed it upon my return to the Caribbean.

katadyn 40e

Katadyn 40E

Overall, I was very happy that I invested in a watermaker.   Fresh showers every day?!  Yes please!

I have no regrets with the Katadyn 40E as it seems to be the perfect desalinator for a small cruising sailboat.  Minimal power requirements and low output was perfect for a solo sailor (and I imagine a couple too).

I’ve been getting some questions about its performance so I’ll attempt to answer them here.

Your Katadyn 40E Q’s A’d

Why did you get a watermaker?

I wanted to be more self-sufficient.  I tend to favor remote locations where fresh water isn’t readily available.  If it is, it isn’t cheap, and schlepping around those heavy water cans is a pain in the ass.

My integral water tank holds 40 gallons.  That’s enough to last almost a month with minimal water consumption.  Once the tank starts to empty, the boat starts to list to starboard a noticeable amount.

It sure felt nice to be able to rinse myself down with fresh water every day, something I couldn’t do before I had a watermaker!

How much power does it draw?

It’s pretty damn close to Katadyn’s advertised 4 amps.

On the push stroke it draws between 4.0 – 4.4 amps and on the pull stroke 3.0 – 3.3 amps.  So that roughly averages out to slightly less than 4 amps.

I ran it for three hours every two days, so I had to budget six amps per day for it.

water can

Before I finished the plumbing I had the desalinator lines coming from under the settee and into a 5-gallon can. I could fill it up halfway in a couple hours and after using a significant amount of my daily electrical budget.

Did you use it at anchor too?

Ehh yes.  I know you’re not really supposed to and I see why.  I only had the one inline filter and that turned a nice slimy green after about a month.

I did my best to run the watermaker during the rising tide so that in theory I’d be getting fresher seawater and not the gross stuff further inland.

I’ll be getting another prefilter to install on the intake next time I’m there.  It’s not very practical to run the watermaker on passages, as you’re supposed to, when island-hopping the Caribbean.

Is the advertised output accurate?

Yep!  I was right at 1.5 gallons per hour with a clean filter.  As the filter aged I noticed the output slightly less but nothing really to write home about.

As mentioned earlier, I operated it for three hours every two days.  The first half hour was to flush stagnant water out of the system (I’d save this for laundry & cleaning water) and the final 2.5 hours went into my tank.  This gave me about 3.75 usable gallons every two days.  At that rate my water tank stayed at just about the same level for months.

I’ve heard it’s a maintenance nightmare.  Is that true?

katadyn cruise kit

The Katadyn 40E Extended Cruise Kit

I never had any problems with it but then again I only used it for five months.  There’s the standard maintenance for all watermakers – oil, grease, inspecting o-rings & bearings – but I never had any malfunctions requiring any extra work.  The preventative maintenance that I did do was minimal and straightforward.

The “pickling” process – getting the watermaker ready for storage – was easy and the directions were very clear.

Now, you also don’t want to get caught with your pants down when you need fresh water and are nowhere near any other sources.  So you do need to carry an ample supply of spare parts and chemicals.  These take up some room and will cost you some more hard-earned money.

I bought the Extended Cruising Kit ($320) just to be safe.  There’s also a Seal Repair Kit available for $140 but the Extended Cruise Kit includes most of this.

It’s noisy isn’t it.

I think “noisy” is relative.  I installed the unit under my settee.  Yes, I could definitely hear it, but it wasn’t annoyingly loud.  I really had to concentrate to hear it while I was up on deck.


Do you have any other questions to add to the list?  Or comments about using the system yourself?

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