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      I have “caught” the diesel bug and may have to remove the diesel tank to replace or clean it. Does anyone know how big a job this is? It looks like it was installed before the locker floor and coachroof were added. Alternatively, does anyone have experience in dealing with the diesel bug without removing the tank (which is an irregular shape and 2.1m long)?
      Many thanks,


      It’s a massive job. The tank is bonded into the hull before any of the furniture is dropped-in so you have to start cutting it up to get it out.

      I would recommend that you get some Marine 16 treatment and see if that sorts it, and if not get the tank emptied and flushed through.

      Try this stuff. It works well:- http://www.seamarknunn.com/acatalog/marine-16-diesel-bug-treatment-100ml-4240.html?gclid=CPGX0PKhhMoCFSoUwwodoJEDew


        Michael, as Bob says its a pig of a job.
        We had this problem on a friends boat (B32 2004) it was caused by the deck filler O ring not sealing. For some reason Bavaria changed the deck filler from the transom to the deck in 2003-4. The O ring seals the filler cap and stops sea water and rain getting in the tank, this was the source of water in the fuel and the dreaded bug.

        A few tips;

        First take all the fuel out of the tank through the inspection hole or the fuel sender hole using a small pump. Machine mart do a 12 volt fuel and oil transfer pump;

        Put it in cans and use for starting fires, lighting the barque. Or treating the fence panels. 🙂
        If you have an inspection hole get an arm in side and clean away the bottom of the tank and wipe the sides. If there is no inspection hole use a rag on a stick to get in as far as you can. Tie the rag on tightly do not use tape. Derv is only explosive when compressed so you could use a aqua vac with a small nozzle. You can get a cheap one here;

        A handy tool to keep on the boat plus it can be used to inflate the dingy (assuming you have an inverter on board)

        Put 20ltrs of white Diesel in the tank. Tesco’s best 🙂 dose it with fuel bug treatment and let it sit for a week.
        Fill up your tank with red derv from somewhere you know sells a lot of diesel.
        Let the fuel settle over night and dose again.

        Every time you fill up use a funnel with a fine gauze filter, it takes longer but its worth doing. available at most chandlers
        Any muck in the funnel get a refund or discount. Like this one;

        Make sure the O ring on the fuel filler is not perished an has a liberal coating of silicone grease. 3 Times a year!

        Hope this helps.

        Best regards.



          Many thanks for the advice Ant and Bob.
          In the end I got a company called LCM to “polish” the fuel and put it back in the tank. That was not easy since the tank tends to overflow if you remove the fuel gauge diesel level detector to gain access. I am planning to fit a MFP2 diesel purifier from MLS between the tank and primary filter to prevent further episodes if the bug comes back. We only had a tiny bit of water in the fuel and we still had a lots of the bug. The purifier has a drain tap to remove water and diesel bug on a regular basis, before it gets far enough to block the primary filter. I might write all this up for the magazine once it is all done and working.

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