Re: full or empty fuel tank
Empty.
This has been done to death but seriously Fireman I'd like to know the ins and outs of your post.
Really curious about what you're seeing, if you couldn't be bothered I'll fully understand because most times I couldn't be bothered either.
It's not so much what I'm seeing (after all, it is a closed aluminum tank) but what I've read and my understanding about the formation of condensation.
I know that metal will react like your windshield on a humid or cold morning. The temperature and humidity difference outside the auto vs inside the auto will always create a film of condensation on the windshield. From my point of view, the metal gas tank will do the same.
If the tank is say, half full, the bottom of the tank sits on the stringers/hull of the boat and therefore will assume a degree of temperature associated with the water underneath. This is the Law of Latent Heat Flow, whereas, heat will flow from a warmer object to a cooler object. In this case, the intrinsic temp of the tank and contents will cool in proportion to the water/hull temp.
Now, the top of the tank sits just inches from the floor of the boat. As the heat/AC is set at 68 degrees during the winter months, it would stand to reason that the top of the tank would, to some degree, assume the temp of the cabin sole. Warmer aluminum on the top and cooler aluminum on the bottom. I know this happens as I can literally feel the 20 degree temp difference when running my hand from the top of the tank to the bottom (large tank - 300 gallons).
I can only assume if it were partially empty that there would be some condensation forming in there due to the temp difference and the fact that it's vented to the outside, but I could be totally off-base. Doing this for 3+ years now, I have never had a fuel/water related problem yet. That could also be due to the fact that I never let fuel sit long enough to truly go bad. I burn the crap out of it. That's why I have a boat. To use it. No dock queen here. None-the-less, I still replace my fuel/water separators every 100 hours and there might not even be a drop of water in them.
If you have a different (read: correct) school of thought, please let me know. I'm always open to learning something that might benefit me.
Thanks for reading.
