fuel tank level

[Riggerman]

I have a 120 gallons diesel tank on a sail boat. But I sail 98% of the time. Only use the engine to set anchor, and to get in and out of a marina. (On the hook most of the time in the tropics). So I rarely use more then 30 gallons of fuel a year.
Should I keep the tank full and risk getting sour fuel, or empty and deal with condensation, or halfway. I use fuel stabilizer, but not sure how effective that is. Fuel in most countries I go is good, but had to clean the tank after fueling in Venezuela, other wise, it is the same fuel in the tank for years, with just a small top off once a year.
Thank you.
J-M
S/V Ete Infini

[FamilyVan]

I have the exact same problem. The 500 litre fuel tank seemed like such a great feature until I realised how long it took to burn 500 litres.
What I do, is I keep the tank full and use a sealed pump with a bit of piping on it that I can reach the bottom of the tank with.
Every so often I pump the water from the bottom of the tank.
I'm still not thrilled with the arrangement. My tank is 35 years old, so I'm actually considering replacing it with a smaller tank.
I also would like the hear others solutions to this problem.

Sent from my SGH-I547C using Cruisers Sailing Forum mobile app

[a64pilot]

I think I'd be tempted to defuel the large tank, preserve it by fogging with 10w oil and sealing it up by closing both the vent an fill port, and using a much smaller tank, then you always have the larger come re-sale time or you decide you need it.

If you only use 30 gl a yr, I assume a 10 gl tank isn't too small?