condensation water in fuel tank

[ArgleBargle]

follow up to a previous post that one or two people might be interested in.

a 120 L ss fuel tank was left 1/3 to 1/2 empty for 2 months in area with relatively high humidity and typ 10-15 deg C difference between daytime high and nighttime low temps.

for a differnt reason (i had a suspicion of some contaminated fuel), i had the fuel "polished" (recirculated at 40 lpm for 30 minutes = 1200 L recirculated volume through separators and filters) while moving (vacuuming) the intake hose to the "polisher" via the inspection hatch to all parts of the tank, especially the dependent (low) parts.

interestingly, there was no, zero, 0 water in the separators.

[Omatako]

The first practical example of how overstated the problem of condensation is. Some believe that fuel tanks are like big dehumidifiers that soak all the moisture out of the atmosphere and deposit it in the tank.

Thanks for the info.

[tager]

So how was the sailing?

[badsanta]

I think most water gets into the tank because of bad o-rings in the cap or it's not tight. The rings get flat because of the fuel and compression. I change mine every few years.

[klem]

I would add one common source as well as the o-rings which is the fuel going into the tank. An awful lot of fuel at the pump has water in it. It is especially bad where there are underground tanks and leaks do not get detected as quickly.