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In Carl’s guest post the other day, he described how the head (toilet in this case, although the word ‘head’ could also refer to the bathroom) can be a very fickle beast, and not one that you want to get on the wrong side of.

“The Head – That would be the bathroom, toilet, or crapper to you land lovers. This is a vital and often finicky piece of machinery on a boat. We all have to go eventually. If you can hold it until you are ashore, you should. Let’s face it, you will need to use it. Key advice here. Your hosts are used to dealing with their own crap. If you screw up the head they will end having to deal with yours. It’s likely that your welcome will rapidly run out thereafter. When you get aboard, learn EXACTLY how to operate the head. Be fastidious in your cleanliness and use only when you must.”

Although we have had many comical (in retrospect) issues with ZTC’s head, it is, for the moment, functioning just as it should (knock on wood). One thing we do to keep “the beast” happy is to give it a liberal dose of salad dressing on a regular basis.

No, not this kind of salad dressing.

Salad dressing? Yes, specifically, oil and vinegar. The Jabsco manual head that we have works by pumping sea water into the bowl and then, with the flick of a switch, flushing the contents into the holding tank. To keep the rubber gaskets and seals in the pump working well, we squirt a few tablespoons of vegetable oil into the bowl about once per week, pumping it through the system. The effect on the pump is immediate. When it needs lubrication the pump will get difficult to cycle and will squeak. After adding the oil it moves effortlessly and is silent.

What about the vinegar? This we add a bit less frequently than the oil but it’s still important. Again, because we are using sea water, the hoses in the head system gradually get blocked off with hard mineral deposits. Although some people use much more caustic substances, we use simple white vinegar to battle this. At a time when you don’t plan on using the head for a while (just before bed at night?) poor a generous amount of vinegar into the bowl. Cycle the pump just enough so that the vinegar gets into the hoses but not enough that it is pumped all the way through the system. Allow it to sit in the hoses for as long as possible before flushing it out completely.

The key point in this system is that we keep containers of both oil and vinegar in the head so that they are handy when needed. I know that if we had to go searching for the stuff elsewhere in the boat, we would be much more likely to procrastinate, lessening the effectiveness of this regular maintenance program. All of the above was shared with us by our friends and it appears to work. If you’re not doing something similar, give it a try.

Simple white vinegar and vegetable oil in a squirt bottle, conveniently kept in the head.


  1. Mike you need to work on the quality of your writing. This one is very crappy. 🙂

  2. He Mike.. congrats on all your tests and stuff…i have found out, from a restaurant person that veg. oil producers do not use the purest and best quarlity of oils and some of those chemicals can ruin gaskets and gum up works..he says mimeral oil is the has been working for us..cheers lad..just another head conversation from a cruiser eh?

  3. Mike, I’ve (tentatively) specified that same Jabsco head for our next boat, whenever it gets built. Since you seem to have become the guru of head repairs, I’ll put the question to you: If you could start from scratch again, would you stick with the Jabsco or would you splurge on something fancier?

    • Simple works for me. Our buddy just tore out two expensive electric heads in his cat and replaced them with manual jabscos. The thing is, they are relatively cheap when compared to some of the fancier models. So yes, I would stick with what we’ve got. It works.

  4. Here’s a cool tip especially when you’re anchoring out a lot…

    Turn off the water intake into the head, dry the inside of the bowl, and wax it with normal boat wax. Seriously. Wax it.

    If you think about it, you’re putting a very thin layer of a slippery surface that’s made to hold for months. You’ll find that you’ll have to clean the head less often. Try it once and see if you like it.


  5. Flick of a switch?????

    Don’t I see a pump handle on that head?

  6. I just spent a Saturday getting very aquainted with the head on ‘DreamCatcher’. Since I had a complete new Jabsco set up in the spare parts locker along with a seal kit I decided to dismantle the beast. The job was staight forward and new unit went in and worked like a charm. I was shocked to see that the old unit along with the hose that feeds into the holding tank were lined with a thick layer of calcium like build up. I can’t believe anything got through with that much smaller diameter opening. It looks like Jabsco uses a silicone grease to lube the rubber O rings like is used for swimming pool seals. We too were using a little cooking oil and vinegar.

  7. If you ever get to the point of replacing your head I can’t recommend enough the “Lavac”. Once you’ve used one of these you’ll never go back to a conventionally designed head that has lots of small passages, valves, etc.

    The Lavac is the ultimate in simplicity with a 3/4″ supply line in and an inch & a half hose going to a large hand operated diaphragm type pump to remove the waste. Any brand of pump will do and it’ll handle most anything you put into the bowl without a clog.

    I’ve never understood why these aren’t seen more often.

  8. Mike,

    Head salad dressing is truly one of the most persistent and hard to kill myths in boating.

    I realize that your salad dressing solution is going to fall into the “It works, so we’re not changing it” category, but…(or should I say butt – groan!).

    The culprit involved with the “hard” pumping is still the calcium/urine crystal build-up that gets solved by the vinegar. The better procedure is to use the vinegar more often and let it sit for as long as possible. Also, in your part of the world, it is better to pump a lot more than you would in enclosed waters where you limit pumping to keep from filling up the holding tank. When I lived on Chesapeake Bay, I pumped enough to get the waste into the holding tank. In the Carib, I always pumped 2 – 4X the strokes to fully wash out the urine from the pump and hose.

    As noted above by Chip (Cara Mia), the oil actually degrades the seals and other rubber bits in the pump.

    From an economic standpoint, you are going to spend more because you have to buy more oil AND you will buy more pump rebuild kits.


    • I am aware that it is the vinegar deals with the build up in the hoses, not the oil. The oil definitely lubricates the seals though. As you said, my experience shows that it works.

      As for the chemicals in the oil breaking down the seals, perhaps. What studies have proven this and what amount of oil over what timespan would be necessary to degrade the seals to the point that they need to be replaced? My bet is significant on both counts. I have not yet had to replace the seals in this head (installed brand new when we were in Washington, DC approx. 1 year ago).

      By the way, you know I love your input so don’t hold back! 🙂

      • Regarding lubrication, Jabsco doesn’t say what the elastomers are, but it recomends Vaseline in the manual; thus, any sort of oil should be fine, though Vaseline as needed is easier. I’m certain this varies with the brand of pump; some use EPDM for seal, which is not oil compatible. One size fits all recomendations may not always fit. My Jabsco has been on a Vaseline diet for 14 years (the tin was stowed with the head parts from the po); the seals seem to be going 3-5 years of light use. I have not seen any evidence that the grease effects them (swelling and softening are the symptoms), and I was staring at them with that in mind yesterday ( the current seals are 3 years old).

        Some hoses are not oil compatible. PVC (white Dometic) is reasonably compatible, while the best available (Trident 102/102) is NOT oil compatible. This is the main reason I prefer grease. Oil can really tear up EPDM.

        As for vinegar, the Chesapeake is brakish and we don’t get scale. It’s a salt water thing. But how much? I would think it might make sense to look in the tank-end of the hose now and then (the head end is too hard to get to).

      • I can’t put my Google aided finger on it, but I know I have heard Peggy Hall (aka – the Headmistress, yes, you can Google her under that moniker), speak about it IRL.

        FWIW, I was pretty religious about giving my heads a cup of vinegar weekly and letting them sit for 12 – 24 hours. Of course, I had two heads so I would do them sequentially.

        Peggy, as I recall, was also pretty high on the Jabsco. Inexpensive and relatively easy to maintain.

        BTW, this is another subject that can get (cough-cough) “out of hand” at any cruiser get together. You are doing well, my young friend.

  9. Hi Mike,
    Not to change the subject but where are u guys heading now? If you are going to Bequia I’d recommend diving there. The dive sites around moonhole are spectacular. Same for the Tobago Cays.
    Good sailing,
    Ted and Rhonda

    • Hi Ted

      We’re not really heading anywhere actually. We just sailed to Carriacou because there is a hash here this weekend. After that we’ll head back to Grenada where we’ll stay until the beginning of November. After that, north and we’ll definitely be stopping at the Tobago Cays and Bequia.

  10. My boat has a S&L head installed in 1970. I have replaced the diaphragm and seals once, approx 15 years ago. It was getting problematic again, then I read of putting olive oil down it, just a small amount once a month or longer. I tried it and it has worked perfectly ever since, that is for the last five years since I started doing this. As you say, it works!

    I have not tried the vinegar trick yet. An alternative is to take the outlet hose off and whack it hard on the shore, or a wall, and break up the deposits. This crude method gives a temporary cure at least.


  11. Hey mike great advise but what is a “quirt bottle”? hehehehe Have you ever though about a composting head?

  12. Thanks for the great tip! While oil may be controversial, we’ll give it a try once we’re cruising!

  13. Mike,

    How often do you have to pump out the holding tank?

    How accessible is a pump out station and what does it cost?

    I vote for the manual pump over and electric. The PO of our formosa put in an electric head and the noise is horrible.

    • Greg: Our holding tank is small and probably only lasts 4-5 days. Be aware though that south of North America, there are NO pump out stations! Many (most?) boats are not even equipped with one, or bypass it entirely. You can figure out the rest.

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