Would this work?

[Norman_E]

The thread on whether or not to fill diesel tanks over winter made me wonder whether internal condensation in part empty tanks could be prevented by filling the tank with carbon dioxide, which is heavier than air and would thus cause the air in the tank to exit via the filler if introduced via a small bore tube put down the filler pipe, and would remain in the tank.

 

[Billjratt]

You're not by any chance keeping old wine in the fuel tank are you?
How's about dangling a bag of dessicant gel crystals in the airspace and sealing all the orifices?

 

[VicS]

Not by simply filling with CO2.
The trouble is that the tank "breathes" as the temperature fluctuates. Moist air will still be drawn in via the vent as the temperature falls, expelled again when it rises, drawn in again as it falls .... and so on.
Each batch of fresh moist air drawn in has the potential to cause condensation if the tank temp falls below the dewpoint of the air in the tank.
Starting off with a blanket of dry CO2 may well delay the condensation but sooner or later its going to occur.


What would work and prevent moisture being drawn is is to fit a silica gel breather on the tank vent.

Goodness knows if they exist in an appropriate size for a boat fuel tank. I've seen them fitted to the vent pipes on big power transmission transformers .

I'd easily make up a laboratory sized one if needed ( in fact I am sure at some time or another I probably have )

I am wondering if simply sealing the tank vent would be acceptable.

 

[LadyInBed]

Not by simply filling with CO2.
What would work and prevent moisture being drawn is is to fit a silica gel breather on the tank vent.

Damn! I thought I was going to come up with a bright idea

 

[rob2]

I have visions of squirting an out of date fire extinguisher down the filler whilst the crew fit condoms over the vents! That should work then...

Actually, it probably would.

Rob.

 

[shaxi]

I think it deserve to have a try if there are no better ideas !