Fuel Polish

We topped off our tanks with diesel fuel before leaving Colombia in 2013. The diesel there is “bio-diesel”, a blend using 10% non-petroleum product. I'd heard rumors of the high growth rate of this stuff, so when another boat in the MAR marina in the Rio Dulce mentioned that they were going to have their fuel polished, I piggy-backed on their service call. In 2003 we converted our starboard water tank to diesel since I wanted more than the standard 38 gallon tank under the cockpit sole. This tank is 32.2 gallons, and was an easy conversion, and included adding another inspection port so we could get at the whole tank. We have a watermaker and are careful with our usage so I felt OK doing this, and this was the tank we needed cleaned.

The guys arrived with a couple of 50 gallon plastic drums, a large Racor filter unit with 10 and 20 micron filters, pumps, and assorted hoses. The cost was about $130 US including two new filters, still in their wrappers, which they were careful to show me. The whole process took about 2 hours and included pumping everything out of our tank then pumping the fuel back and forth four times between their drums through the filters, cleaning out residue in the tank, then pumping the fuel back into it. I opened and closed the inspection plates since I didn't trust them to not strip the bolts.

Apparatus

Pump-Out

I was surprised that there wasn't more growth in the tank, but I think having tanks that don't touch the hull and being in a warm climate with no condensation really helps. I felt sorry for the other boat, a Hans Christian 48T, since they couldn't get at the aft 100-gallon tank inspection plate without a major disassembly job and it didn't give access to the whole tank anyway. They had to make an adapter from their fuel supply line.   

Before

After