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The Official Magazine of the Bluewater Cruising Association

Lessons Learned... The Hard Way: Contaminated Fuel Tank

David Smith

Fast Passage 39.6 Cutter
December 23rd, 2014


Contaminated Fuel Tank




I was single-handing from Golfito to Panama City. The first leg to Cabo Malo (‘bad cape’) was a three-day trip, followed by an overnighter along the coast to the anchorage at Cabo Malo. For the overnighter, I left at 1600h in hopes of arriving at Cabo Malo around noon the next day. All went reasonably well until the final 15 miles up to the Cabo Malo anchorage where I planned to wait for good Gulf of Panama crossing weather (another overnight passage in busy shipping routes) and to rest.

As I rounded the final turn into the 15-mile stretch to the anchorage, the wind picked up to 35 knots on the nose and the waves became extremely steep. There was no safe place to anchor so I powered into the swells. I was making reasonable headway at about 2 knots until eight miles before the anchorage, when the engine suddenly quit. I was in 125’ of water and had no choice but to drop anchor and hope for a grab on the bottom. Luckily, my 66-lb Bruce and 5/16″ chain held in the wind and rocking/rolling sea while I made repairs.

Mistakes Made

I knew I had a contaminated main fuel tank (paper in the fuel). I had added two hand-hole clean-outs in my main tank in addition to the one I already had. Unfortunately, it was only when I cut into the tank that I realized the tank had 4 quadrants. When I installed the hand-hole clean-outs, I wasn’t near a fabricator to make a 4th hand-hole cover, so I was only able to thoroughly clean 3 of the 4 quadrants.

In general, I was diligent with my Baja filter and jerry jugs but not diligent enough. Somehow I allowed contaminated fuel into the main tank in Central America. But fuel problems had plagued the boat for 10 years before this incident. I had controlled this by annually pulling fuel from the bottom of the tank and filtering the sediment through my Baja filter.

Lessons Learned

  1. Make sure your tanks are pristine clean before you leave your home port.
  2. Have clean out holes in every quadrant of your tank(s).
  3. Add biocide with every fuel fill.
  4. Buy and use a Baja or funnel type fuel filter for every fuel fill. Make no exceptions even if you are in Canada or the US!
  5. Know how to bleed your engine so that you can do it in your sleep. Like me, you may be called upon to bleed the engine in very difficult circumstances.
  6. Have a good anchoring system, as your anchor and chain hanging in deep water are very heavy. You will need a strong windlass to lift this weight.


  1. Located the fuel blockage and removed the obstruction.
  2. Removed and replaced all fuel filters
  3. Bled the engine fuel system.
  4. Switched to the auxiliary tank as the main tank could not be trusted to be completely free of contamination.
  5. At first opportunity, I installed a 4th quadrant hand-hole in my main tank and thoroughly cleaned out all tank quadrants.

Have a Story?

We have all made mistakes and learned valuable lessons the hard way. Do you have a story you want to share with BCA members so we can learn from your experience? If so, please submit it for publication in this column using the section headings ‘Submitted by’ through ‘Lesson Learned’ or ‘Repairs’. Thanks!

Send your story to with ‘OOPS!’ in the subject line.


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  1. Avatar Ken Wright says:

    May I add one suggestion to Dave’s Repairs comments .
    keep the necessary tools ( usually a 17 mm spanner for the injector nuts, and a 10 to 13 mm spanner to open
    and close the bleed screws on filter top and high pressure pump) handy….hanging on hooks in the E/R .
    I note from the picture that he has quite a complete fuel filter assy , c/w vacuum gauge (I think), and dual
    model 500 Racor filters fitted in parallel, a container of clean(already filtered) fuel nearby, and ( I think)
    an electric fuel pump.
    well Done !