Steel tanks over winter

OK, here's a question for the collected wisdom of TF:

When leaving two 500 gallon mild steel water tanks unused for 11 months, is it best to leave them empty or full? I've done both and not noticed any particular difference.

In any event they will be flushed before the next use.

Scott Welch
Island Eagle

Flushing will perhaps clean the fuel in the tank , but not clean the tank one bit.

I would go with full, with a good dose of a different brand of bug killer than you usually use.

AND an attempt (hopefully a bottom drain) to get all the water out before storing.

IslandEagle said:

OK, here's a question for the collected wisdom of TF:

When leaving two 500 gallon mild steel water tanks unused for 11 months, is it best to leave them empty or full? I've done both and not noticed any particular difference.

In any event they will be flushed before the next use.

Scott Welch
Island Eagle

Click to expand...

RickB suggested a few days back that empty and fog them would be best. I would agree..but ...hard t argues after so many have done for so long is full/stabilized if the fuels is consumed within a relatively sort time after coming out of storage. 11 months is as long as I would like fuel to sit without use and not being polished.

I would never do it with ethanol fuel for those reading and have gassers.

... mild steel water tanks unused for 11 months ...

Click to expand...

If you can dry them completely and keep them bone dry then do that. Otherwise, filling them completely with cold, clean, fresh water will provide a low oxygen environment.

If they haven't decomposed in the past 11 months of normal use with a constantly refreshed supply of oxygenated water sloshing around, they won't fall apart by being protected by a shield of clean water.

RickB said:

If you can dry them completely and keep them bone dry then do that. Otherwise, filling them completely with cold, clean, fresh water will provide a low oxygen environment.

Click to expand...

That was my thought as well.

If they haven't decomposed in the past 11 months of normal use with a constantly refreshed supply of oxygenated water sloshing around, they won't fall apart by being protected by a shield of clean water.

Click to expand...

Well, I've had the boat for 10 years and only use it in the summer, and the tanks are 50 years old, so I'm not so worried about them falling apart

It's more a question of which option will lead to less-metalic-tasting water next summer.

Scott Welch
Island Eagle

FF said:

Flushing will perhaps clean the fuel in the tank , but not clean the tank one bit.

I would go with full, with a good dose of a different brand of bug killer than you usually use.

AND an attempt (hopefully a bottom drain) to get all the water out before storing.

Click to expand...

The tanks in question are water tanks, not fuel. My fuel tanks (dual 1000 gallon) are also mild steel, with a nice big bottom drain and a 250 GPH pump with dual Racors for cleaning the fuel in the spring. Never a problem, full or empty.

Scott Welch
Island Eagle

psneeld said:

11 months is as long as I would like fuel to sit without use and not being polished.

Click to expand...

I have used very old (>10 years) diesel with no ill effects, although not in my boat. However, this was in old-school mechanical engines, so YMMV.

In the case of Island Eagle, I last filled the tanks in 2008 and the old Detroit 6-110 has never missed a beat. I did have a bit of gunk in the Racors this year, though. I'd guess that the climate where I store the boat (Pacific Northwest) helps.

Scott Welch
Island Eagle

IslandEagle said:

apart
It's more a question of which option will lead to less-metalic-tasting water next summer.

Click to expand...

There is always the old fashioned "cement wash" technique. It has been modernized a bit but is still a good way to achieve corrosion protection and removing metallic tastes.

Applications For MarineCoat : Astek Composites Inc.

I haven't had any problems with taste from steel tanks but maybe it depends on the water source. If your water supply is acidic you might want to add a bit of caustic soda but don't let the pH go above 11.