Big tanks aging fuel

Where I've seen condensation is not in the boat, but in the marina. In some areas, low volume marinas decide to not spend the money before the winter. No when you're talking about an underground tank which holds 10,000 to 50,000 or more gallons of gas it's a very different situation. Even then properly watched it won't be a problem. I use to watch the marina I frequented measure the water in their tanks. Often it would be four to six inches. But their pickup was a foot from the bottom.

In boats themselves, it's always been other problems with their fuel that I've seen over the winter, not condensation.

" I use to watch the marina I frequented measure the water in their tanks. Often it would be four to six inches. But their pickup was a foot from the bottom. "

I hope to not fuel in a place like that just after they have had a delivery from the truck and stirred all the water in the bottom of their tank into all of the fuel in the tank.

Probably more common than we all wish.

Ski in NC said:

I too really doubt the condensation issue really exists. I keep my tanks at low level most of the time to save weight, and have never had a drop of water in either the tank or the racor. 8yr and 2000hr. Not a drop. NC also has some serious temp/humidity swings, especially in spring and fall.

But the tank fills are under the deck hatch. And the vents go through a custom made liquid separator.

I suspect most of the water in tanks comes from leaky deck fills exposed to sea spray and weather, and poorly done vents.

Aircraft are different as the tanks get some serious temp swings with altitude changes, and tank skin usually is directly in contact with the air stream. Big temp swings. Not so much on a boat.

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After 12,000 gallons or so of fuel the amount of water I have drained from my Racors is none, as in zero. The tanks are never more than half full, as I buy fuel a thousand gallons at a time, and by the time winter comes, they are frequently only 1/4 full. The initial load of fuel on the boat when I bought her was 4 years old when our refit was done, and while I polished out a bit of black stuff and noticed that the engine smoked a tiny bit more burning that fuel than fresh, there was no discernible difference between fresh fuel and stuff 4 years old in terms of performance. I replace the polishing filters for drill each year and this year there was no more than a teaspoon of black deposits on the filters, even though I polish when the tanks only have 75 gallons or so when sloshing around in a seaway. In other words, there is no moisture, no crud, nothing in these tanks. I opened the drain at the bottom of the wing tanks, also for drill and all that comes out is clean fuel.

Many myths are just that. Myths. However, if your fuel source has water, so will you. I don't because our fuel comes from the refinery 5 miles away, with natural tank condensation contributing nothing in that regard.

BryanF said:

" I use to watch the marina I frequented measure the water in their tanks. Often it would be four to six inches. But their pickup was a foot from the bottom. "

I hope to not fuel in a place like that just after they have had a delivery from the truck and stirred all the water in the bottom of their tank into all of the fuel in the tank.

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That's one of the safe marinas. It's very common for underwater gas tanks to have some water. That's why checking them is important. Gas stations also monitor theirs, or the good ones do.

I think the fuel quality in the SE USA is poor. I think the fuel quality in the NW USA (and Canada) is good. And that is the crux of the problem. It probably has something to do with the either the choice of cat cracking or hydro cracking and the feedstock to the refinery in the areas.

Condensation in some storage tanks is real; condensation in my boats fuel tanks is not. I suppose that hot fuel with water held in suspension will precipitate out when temperature drops, and that might be a factor in the SE fuels due to climate. I saw the compass marine trial. I thought he was daring to suggest a counterargument, but I think he is right, at least for his weather conditions.

I did have asphaltene precipitation in my old fuel when I first purchased the boat. Filter took care of it.

I was told to read the MDS sheets for diesel and you will see that all diesel has some water in it from the refinery. I haven't for a long time so I do not have numbers. Add in the transfer from the tanks, pipelines, trucks etc. and you have water content. If you keep it moving or stirred it will stay in suspension and be burnt or under the correct circumstances it will support the growth of organisms.

Spinning filters take care of any present.

Measure the size of your fuel tanks, then find out how much moisture can be supported by that volume of air at winter temperatures in the tank, assuming very little air circulation and figure out for yourselves how much water will condense out of that air. Minuscule amount.

cafesport said:

it's not always a good idea to have your engine return fuel to the main storage tank. Food for though.

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Where else can it go?

In Canada the law requires that diesel be returned to the tank from which it was drawn.

MSDS, material safety data sheet. I've never looked at one for diesel, interesting.

boatpoker said:

Where else can it go?

In Canada the law requires that diesel be returned to the tank from which it was drawn.

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We return fuel to the tank the engines are drawing from to ensure that we don't overflow a tank, but I'm curious what the reason is for making it a law to return fuel the main tank? How does the law define main tank?

Where else can it go?

In Canada the law requires that diesel be returned to the tank from which it was drawn.
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Boatpoker,

I was not aware of that rule. I went looking for it and after my eyes glazed over I still cannot find it.
Can you point me in the right direction please?

I do not now follow that rule. Single engine and I run the return lines throttled to try to keep the boat somewhat balanced as fuel use DOES materially affect listing.

Thanks

C lectric said:

Where else can it go?

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In our fuel system the return can be valved to go to any of the five tanks regardless of which tank or tanks the engines are drawing from. I assume this was done so the return fuel could be diverted from a tank that developed a problem. Or if we elected to feed the engines from a tank other than the day tank, the return could be sent to the supply tank.

Yes, understood. My system is simpler, one engine, two tanks with ability to pull from either tank and return to either tank.

It was more a matter of Boatpokers point about a rule/law that , in Canada, you MUST return to the tank it was pulled from. I just wanted to know where to find that rule as I cannot , so far, find even a hint about that point.

I pull from both tanks and return to both but throttling the return on one tank that gets the least draw, by a lot, so most of the return fuel goes to the tank that sees the most draw.

Construction Standards for Small Vessels.

TP 1332E para. 7.4.11.

Note that it is a construction standard.

I've been on a boat where someone screwed up the valving and the Detroit ended up sucking off one tank and returning to another. The tank returned to went "solid" and 100gal pumped out the vent as boat went along. Detroits return lots of fuel.

It's a situation worth avoiding, whether codified or not.

Two things to note:

1) There is a lot of disagreement on the idea that there is enough air space to really cause much, if anything, in the way of measurable condensation on tanks as small as ours (toy boats ) Read up on it and draw your own conclusions, but I, for one, agree that any condensation that could possibly build up would never cause in issue. But that's just me.

2) I would be very cautious about using additives in fuel without know what is in the fuel already. The large storage depots MAY have put something in it already. So you can do more harm than good. A few real industry experts have passed through here and they have left some good advice. (see below)

The best advice you are now unable to really accomplish. While fuel may not go "bad", stuff grows in stagnant fuel. The best advice the experts gave us is to just use your fuel. You really should go through your fuel in 90-120 days (not my number). You can get it tested and get your tanks "dipped" to see if there is water in the bottom, and even get it scrubbed professionally. But full tanks would be a bit pricey to have scrubbed.

Hope this helps.

Got it.

I did understand the why. I just could not find the rule.

Thank You.

Tom.B said:

The best advice the experts gave us is to just use your fuel.

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Now you're talking about something we can definitely do and do well. We've never been 90 days without the need to fuel.

Does anyone have proof (verified by themselves) of biologics growing in a boats diesel tank ????? I mean you actually looked at fuel from your tank under a microscope and personally witnessed live organisms. I'm calling BS on this old wives tail until I get proof.

kulas44 said:

Does anyone have proof (verified by themselves) of biologics growing in a boats diesel tank ????? I mean you actually looked at fuel from your tank under a microscope and personally witnessed live organisms. I'm calling BS on this old wives tail until I get proof.

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DIESEL FUEL "BUGS"

Diesel fuel "bugs" can cause fuel filters to block., with subsequent engine malfunction, or worse still, engine stoppage.

Diesel fuel "bugs" are actually micro-organisms comprised of fungi, yeasts and bacteria which live mostly in the diesel / water interface inside the diesel tank. The common diesel ‘bug’ is the fungus Hormoconis resinae that can produce a large biomass of mycelia (fungal matting) in a short period of time if the conditions are favourable. Hormoconis resinae is called "diesel bug" in the diesel fuel industry and "jet fuel fungus" in the aviation industry.



The mycelia of Hormoconis resinae excrete acids that can break down weaker tank material such as aluminium.

Water, nutrients and warmth are the pre-requisites for "bugs" to rapidly grow, blocking filters and damaging engine fuel components. Water can be either free water (fresh or salt) or emulsified water. Free water may have come from faulty bulk storage tanks, or from rain or sea water entering through fuel tank filler caps with faulty seals. Nutrients can include the alkanes in the fuel, dead "bugs" and even the fuel tank material. Warmth is usually from the local ambient conditions, but diesel tanks in engine rooms and non-cooled high flow return lines into small fuel tanks will increase the diesel tank temperature.

Long storage of diesel fuel also increases the potential of "bugs" to grow.

Oh, and I did not personally witness the 'bugs' other than the messes I have dealt with for decades that resulted from their existence. The scientific community is good enough for me on that score.

kulas44 said:

Does anyone have proof (verified by themselves) of biologics growing in a boats diesel tank ????? I mean you actually looked at fuel from your tank under a microscope and personally witnessed live organisms. I'm calling BS on this old wives tail until I get proof.

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Kulas44 I don't think too many people are going to use the microscope. But I think there is a wee problem with the way you are looking at this. If you demand personal visual proof for this, using your own logic you would have to do it for so many other things it would be almost universal. Often the best we can get is evidence presented by people or organizations expert in their field hopefully using good scientific methods. I am not a expert chemist with specialty in fuel but I was trained as a scientist and have read multiple accounts written by experts and others released by fuel and chemical industry people. Unless you chose to completely deny the validity of the science here ,be advised that things do grow in diesel fuel particularly in moisture(H20) in fuel. Also despite some common misunderstanding by several on this site diesel fuel does deteriorate with time and exposure to oxygen and small particles of aspertine are formed. The fact that engines will run on old suboptimal fuel does not in any way prove that fuel does not deteriorate. This also does not mean that your engine is not being affected in an adverse way it only means you do not have the means to measure it. Diesel engines are commonly abused by poor maintenance and abusive use and still keep running for many years. You just don't want to be buying that engine in a used boat no mater what the previous owners opinions. I would think the same would hold for fuel tank and fuel management.

I agree that diesel gets older with age and either does or does not change. Really old diesel seams to run just fine, dont know about the new stuff, none of it is old enough yet. However, I'm still looking for personall experience of anyone on this forum that has actually seen anything alive in his/her fuel tank. I will agree with the formation of acids or other compounds produced by fuel and water but not by "bugs" or anything alive. I can produce any kind of evidence from any kind of scientist backing up any kind of argument about any subject you like, the internet is good that way. I still have not met anyone that has seen these "bugs". Still callin BS.

Can't speak for diesel fuel, but I have seen "bugs" that lived in the water/fuel interface in jet fuel here at Boeing. We did a film a whole bunch of years ago about this and how our fuel people test for it and so on.

kulas44 said:

I still have not met anyone that has seen these "bugs". Still callin BS.

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I guess this depends on your "belief system", assuming belief systems, not being visible, really exist . I`ve heard the comment "you don`t have to visit a sewer to have a fair idea of what flows through one" . I think I`ll accept the word of the "experts" on this one. Even if some "experts" are also selling biocides.

Having recently been an intervenor in a Canadian National Energy Board / Canadian Environmental Assessment Agency Joint Review Panel battle regarding a BIG diluted bitumen pipeline & supertanker port proposal for my home town and channel, there is indeed such a thing as bacteria in petrolium products.

In the case of pipelines, in areas where sludge deposits form, bacteria can thrive and their byproducts can eventually eat through and cause full bore pipeline ruptures.

(Decision on project mentioned above is hovering in the background and looks to be dead...waiting for Plan B to be trotted out...)

kulas44 said:

... I can produce any kind of evidence from any kind of scientist backing up any kind of argument about any subject you like, the internet is good that way. I still have not met anyone that has seen these "bugs". Still callin BS.

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I've got good eyes but we're talking microbial contamination at typically what, 0.5–5.0 micrometers in length? ASTM even has a test for them little buggers. ASTM D6469-14, Standard Guide for Microbial Contamination in Fuels and Fuel Systems. Dow also has some info.

http://www.hpcdfuel.com/pdf/DOWfuel_training.pdf

Marin, that's comforting. I only fill up two of four fuel tanks at a time, about nine months at a time. Have not yet experienced fuel-water problems either..

kulas44 said:

I agree that diesel gets older with age and either does or does not change. Really old diesel seams to run just fine, dont know about the new stuff, none of it is old enough yet. However, I'm still looking for personall experience of anyone on this forum that has actually seen anything alive in his/her fuel tank. I will agree with the formation of acids or other compounds produced by fuel and water but not by "bugs" or anything alive. I can produce any kind of evidence from any kind of scientist backing up any kind of argument about any subject you like, the internet is good that way. I still have not met anyone that has seen these "bugs". Still callin BS.

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Then I'm calling BS on your BS. Fact is what good would it do if we had personal experience? Why would you believe us when you won't believe scientists or experts? After all, you insist on personal experience, so I'd suggest running your own tests. Get some samples of fuel, put it in various tanks of various materials, let it sit, get your microscope, also maybe set up a lab of your own.

I really don't get why you find it so hard to believe fungus and bacteria can develop in fuel. You have bacteria throughout your body, maybe fungus too. Open a bottle of water and leave it sitting a while and see all the bacteria in it. Take plastic containers and look at the bacteria left in their sides as they age. I have actually looked through a microscope and seen the bacteria in swimming pools, spas, water supplies, colas left open, and various other liquids including alcohol that classmates thought couldn't possibly have any. But you're right I haven't looked under a microscope at gas or diesel. I've just read.

I'd add too that all those things you acknowledge as possible such as acid and compounds, all the gunk (wanted to use a very scientific word for you), the deterioration of tanks over the years, all those things only increase the probability of bacteria.

So, Marin is the only one here. I still have to ask him "did you personally see the biologics yourself". I would love to find some of them, and see it for myself. I have been around diesel most of my life and looked at some nasty stuff from storage tanks. I never once thought it was alive, or had ever been, but I could be wrong. I dont put any faith in biocides or snake oil, or any additives for that matter, in diesel fuel. Old fuel that has been stored in stationary tanks can benefit from adding a little unleaded gasoline, just to help break the "strings" that are said to form, or spends more $$$ on something else to do the same thing. At the least it doesnt hurt anything. But, the newer ultra low sulphur diesel may be totally different. Maybe it grows bugs better. I do know that the WMO/gasoline mix that I've been using doesnt seem to have any bugs, I dont think anything can live there. But i've always thought that about diesel to. I can kinda understand a large stationary tank, where the water/fuel doesnt move, but a mobile/moving tank would not seem to be a good place for the critters to set up homemaking.

I have had what they call algae in my sailboat tanks...Ft Lauderdale, several year old fuel with no biocide...

Definitely not dirt, crud or asphaltines. Definitely something I had never seen before.

Confirmed by the mechanic.