My brother has a sailboat with a 250 gal water tank and a 150 gal diesel tank. He also has a water maker, so he wants to swap the two tanks (carry 250 gals of diesel and only 150 of water). Is it possible to purge and clean the diesel tank so it can hold potable water? And if so, what's the process?

I'd think it's pretty easy to clean and dry the water tank to make it hold diesel, but the concern is the other way around.

He said swapping the lines around is pretty easy if it's possible to make the diesel tank safe for potable water. Thanks!

 

THE TRUCKS CAN RUN ON CORN OIL AND GRANOLA OIL, SEEMS LIKE A LITTLE BIO DIESEL IN OUR SYSTEMS WOULD BE OK

 

We use a biodegradable, water soluable degreaser at work, you might try something like that to clean the inside of the tank.

 

I wouldn't do it depending on what kind of tank it is. If it is ABS or some kind of plastic it is possible. Just clean it of REALLY good. You wouldn't want to drink diesel flavored water. It it is a metal tank you may never be able to clean it out well enough to hold water. Metal is slightly porous and the fuel permeates into those pores.

I was on a large Coast Guard cutter before coming to Guam. That ship held a little over 200,000 gallons of #2 diesel (or #1 if we went to Alaska). The tanks were made of steel like the rest of the hull. Every few years we would have contractors come out to clean the tanks. With the tank pumped out and dry, you can still smell fuel. We had to have continous ventilation to be able to work inside the tank, and even then you had to have a fume respirator to be able to work for any period of time.

 

I would recommend replacing the 150 gal tank with a new one so you don't have issues with the water later on when you are way out and need a drink. I doubt if you could wash the diesel tank out clean enough to not get some residue after setting a few days. I don't like to spend my vacation time on the throne because of bad water.

 

you might consider if you enough access to the inside of the tank to install a bladder. I would not use the tank istself for potable water no matter how much cleaning you did with it and what it is made of. If not then replace the tank. DO NOT TRY TO CLEAN THE TANK OUT USE IT FOR POTABLE WATER.

 

I used to work for a co. that had tankers for hauling fuel. When we worked on them we would steam them for 8 hours at the end of steaming the order of gas or diesel was gone. But when they were moved to another bay to be worked on, the flexing made the order come back. I don't think this is a good idea.