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      I recall several posts from the old forum complaining about blocked holding tanks on the newer boats. I understand that part of the problem is that the cunning designers have included right angle bends in the outfeed pipe and the outflow is only gravity fed.

      I had a holding tank factory fitted as an extra on my June 2000 boat and they included a macerator pump in the outfeed. To date I have had no blockages and no longer take any special precautions.

      Maybe this is the right long term solution. If anyone is interested I will find out what pump is used.


        We bought a Bavaria 41 earlier this year and thought that on a newer boat (2003) we would not have the same problems that we encountered with our previous boat. The holding tank has been continually blocked and we have been unable to clear it. We have considered a macerator pump to be fitted when she is laid up, so noting your success it seems to be the way forward. I would be interested to know what the pump is.

        Mike Buxton


          Very interesting to hear about the macerator.

          Having had this problem several times over the last 9 months, on both heads; and with the aft head blocked for an entire 3 week cruise, we are keen to get this fixed.

          I understand that there is 2 problems:

          1. The ball valve hull fitting requires the waste to turn almost 90 degrees. This frequently blocks with non-liquid waste including paper. (Actually I got a letter from Opal just a couple of weeks ago recommending no paper at all be put down the toilet). Opal have agreed that the valve needs to be changed which I expect they will do under warranty.

          2. The shape of the bottom of the holding tank encourages blockages especially if paper is used without much water.

          So I wonder if the macerator fixes 1, but to fix 2 the solution seems to be pump lots of water through. We are now using 15-20 pumps of the handle !

          We spoke to a guy from Jabsco at the boat show. He said that a macerator pump would be less useful than a diaphragm waste pump between the holding tank and ball valve. He also recommended an electric flush which uses much more water!

          Can you say how you use your macerator. Do you usually fill the holding tank and switch on the pump from time to time ?


            The pump fits between the holding tank and the ball valve. I empty the tank when we are a suitable distance from the shore, usually before the tank is full (we generally only sail two up). We use plenty of water with each flush and paper as required.

            I will take the pump details when I visit the boat this weekend and post them here next week.


              The pump is from Sealand in the USA. It’s their T series – see the following web-site –


              Scroll down to the Discharge and Macerator Pumps section.

              I note it’s not cheap (but the Holding Tank option cost me around £750 in 2000). It does seem to do the business, though.


                I was told about this problem before I bought my B36 earlier this year so I had a pump out fitted. ( It did not work 😥 ) still blocked up but you can flush from the top.

                “Playtime” could you take some photo of the macerator fitted.



                  Our holding tank eventually filled to bursting and failed to empty at sea due to being blocked. Being a Bavaria of recent vintage it turns out there is no means of pumping out without retro-fitting a deck attachment.

                  The solution was very simple and very inexpensive but rather unpleasant in the “doing” as all we did was purchase a 6 foot long flexible drain rod from the local hardware store for £5.

                  We then cleared the blockage from outside the hull by means of a stripped off skipper (me) alongside in the dinghy with said flexible rod in my surgical-gloved hands. Thank the lord for barrier cream to start and a transom shower to finish!


                    Following all the traumas of blocked tanks, manually pumping out from the deck fitting and trying to poke flexible cable up the skin fitting we finally decided enough was enough and fitted a macerator pump. This fits between the tank and the ball valve and is a Jabsco 18590-2092. What a transformation. In the last 2 years we have had only one problem when it would not pump out and this was easilly remedied by reversing teh polarity on the pump. We are still careful what we put down. We sue the dissolving toilet paper, which really works, and is cheaper from camping shops. We also use lots of water to flush. Also when pumping out, and you think the tank is empty, pump more water in which seems to dislodge solids stuck at the base. Be warned………………dont try and flush more water through the toilet whilst you are still pumping out as you will get your own back!!!



                      achilles/ipswich after the second blockage we thought about macerator pump ended up with the jabasco electric replacment noisey but havent had a problem since as the macerator grinds it up before it gets to the tank with plenty of water expensive, noisey but solved the problem .you can get the quiet electric replacement but has water pump and macerator pump on a pump in pump out circuit.my one has macerator pump in the stem with twist switch on top.


                        Dear All,

                        I had the same problem on my 36 since new but of late much worse, so I was also thinking of an electric replacement loo or macerator. My friend suggested that before spending a large sum money why not try some porta poti fluid as this should break down the content of the tank. So far this seems to have worked, at least for the last two weekends and the tank smells a lot better. We are away next weekend for the week so should be a good test of how effective this is. I will keep you posted.

                        Keith & Carole, Wave Dancer


                          There’s a simple way to clear a blocked holding tank.
                          Get a crew member (the wife) to put their fingers over the air vent which exits thro the hull just below the toe rail. Then pressurise the tank by pumping in water via the toilet flush – you’ll very soon hear a satisfying ‘swoosh’ as the tank drains. Its worked several times for us, though now we flush less toilet paper the problem hasn’t reoccured.


                            Dear all,

                            As promissed an update on using elsen blue. we have added this to the tank for over a month now and so far no blockages this includes being away all last week. we add 200ml to the tank via the loo and vent the tank when we are at sea with no problems.

                            Keith & Carole, Wave Dancer.


                              I’ve fitted Jabsco Electric Conversions to two of the heads on my B47. They have a built-in macerator, and are very simple to fit. Only downside is that they are noisy enough to wake the dead!


                                put some porta potty fluid into the tank.
                                It will break down contents

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