Fuel tanks and their Compartments 2

Now we have the Starboard tank space repaired, and before I transferred the fuel from the port tank, I thought that it was time to look at the modern problem of the "Diesel Bug", this wasn't even heard of in the 1960's when the boat was built, but is now an ever increasing problem.

"What Is the Diesel Bug ?The introduction of up to 7% Bio Diesel has caused diesel to become more susceptible to the effects of water and fungal contamination known as the DIESEL BUG.
The diesel bug infected fuel will be drawn into your fuel lines clogging fuel pumps, injectors and inline fuel filters. Microbes that live at the interface between water and diesel fuel are what are commonly referred to as diesel bugs. It is the water in the fuel tank that the diesel bug survives on and allows it to reproduce at an extremely fast rate. The term "Diesel Bug" is a commonly accepted term for a number of contaminants that include microbial bacteria, fungi and algae.
The microbes have a very short life, but multiply and produce waste deposits before they die and descend to the bottom of the fuel tank. Due to the rate of reproduction the build up of dead microbes can be quite fast. They need water to survive and any fuel tank with an air pocket will produce condensation when the temperature falls far enough. This is why aeroplanes fill their tanks when left to stand (to reduce the size of the air pocket) and have water drainage taps to release the condensed water from the bottom of their fuel tanks. Engine failure when in flight is a tad more risky than when afloat or on wheels.

When dead diesel bugs, sludge or water is sucked into the fuel lines the resulting filter and injector blockages can cause engine failure and an extended and dirty tank cleaning exercise, with the added annoyance and expense of lost contaminated fuel inside the tank.
Diesel bug additives have been developed to kill the bugs but the additives do not remove the dead bugs, relying on the engine combustion to burn them off.  This does not appear to work with all engines, as some engineers will opine, and neither will the additives remove the water, sludge and rust deposits that still sit in the bottom of the tank alongside the diesel bugs. New sulphur-free diesel with a bio diesel element is also more prone to contamination by bacteria, and this again can cause blockages and corrosion."

I wanted to leave the fuel system as original, not replacing the original filters with modern alternatives, after all I am doing a restoration, not a re-build! I therefore decided to add a fuel "Polishing" system. This is not used when the engines are running. It is used to "circulate" and filter the diesel by pumping it from the tank, through a fine filter & water separator, and then returning to the tank. This is done when the boat is not being used. I also decided to add extra facility for fuel transfer between tanks and "Back Flushing" of the main feeds. This along with the new dip pipes for fuel sampling/water extraction should help me get trouble free boating.

After my little diversion from restoration we carry on with the re-fitting of the tanks.

  • building the fuel polishing, tank transfer system building the fuel polishing, tank transfer system
  • the fuel polishing layout the fuel polishing layout
  • fUEL POLISHING SYSTEM IN SITUE, JUST PIPEWORK TO TIDY UP, AND ELECTRICAL SUPPLY TO ADD. fUEL POLISHING SYSTEM IN SITUE, JUST PIPEWORK TO TIDY UP, AND ELECTRICAL SUPPLY TO ADD.
  • piped up and tried out, just need electrical circuit piped up and tried out, just need electrical circuit
  • Stbd Tank cradle re-fitted, LOOKING AFT, Bilge dip pipe to be fitted. Stbd Tank cradle re-fitted, LOOKING AFT, Bilge dip pipe to be fitted.
  • looking forward, tank strap brackets& bit of painting to do, nearly ready for tank looking forward, tank strap brackets& bit of painting to do, nearly ready for tank
  • PAINTING DONE! PAINTING DONE!
  • READY FOR TANK READY FOR TANK
  • TANK BACK IN ITS PROPER PLACE! TANK BACK IN ITS PROPER PLACE!
  • TANK PLACED IN, FILLER PIPE FITED, NEW BILGE PIPE FITTED TANK PLACED IN, FILLER PIPE FITED, NEW BILGE PIPE FITTED
  • Before Before
  • after after
  • tank space & pipework looking forward tank space & pipework looking forward
  • general view looking aft general view looking aft
  • Port tank, as opened up! this is why we have to treat the diesel bug! steam cleaning needed. Port tank, as opened up! this is why we have to treat the diesel bug! steam cleaning needed.
  • Port tank now in and awaiting fuel pipes Port tank now in and awaiting fuel pipes
  • Port tank with extra "dip"pipe outlet, for cleaning Port tank with extra "dip"pipe outlet, for cleaning
  • tank showing new position after self righting conversion tank showing new position after self righting conversion
  • Fwd end, in and piped Fwd end, in and piped
  • Aft Aft
  • Fwd looking Fwd showing new flexible pipes, water extraction pipe, er bulkhead fittings. Fwd looking Fwd showing new flexible pipes, water extraction pipe, er bulkhead fittings.
     
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