Ethanol Fuel Seperation Problems

[Mark42]

Re: Ethanol Fuel Seperation Problems

so my question is
where are the industry tests/research/experiments to prove or disprove all these different opinions.
And if water does form/leak into/come with the gas in boat fuel tanks why is not there a pump out line to the tank bottom?

are gas deck tank fill caps certified or tested in any way to prove their ability to keep water out, when like under way or in heavy rain?

I don't know about being certified, but some deck fills are better designed than others. The fill I use on both my boats are investment cast stainless steel with "O" ring seal. When tightened, the O ring is compressed making a positive seal. One fill sits horizontal on top of the bow, the other is close to vertical on the back of the boat. So far, neither have leaked. Its also important to have a well designed vent that is placed properly.

Here is the deck fill (Sea Dog # SDG-3513201) and cast stainless vent (Sea Dog # SDG 3522101) I used when installing a permanent plastic fuel tank. It was important to ensure that the vent is higher than the tank to prevent siphoning, but also to have a riser to prevent water from easily entering the tank. The vent hose rises from the vent, loops over the top of the fill neck, and then drops down to the tank. Water has to enter the vent through the two down facing holes, pass the screen, rise over a foot vertically, before being able to run down hill into the tank. Being that this vent is on the transom, and does get hit by water when dropping from plane abruptly, no water has entered the tank from this vent since being installed prior to last season. Also, note that the deck fill can't have water pool on top of it, and eventually leak in. The clear bowl water/gas filter never showed a drop of water in two seasons. The boat is always filled at gas stations, not marinas.

No water leaks in, no water condenses. With the deck fill tightly closed, the only way for air to enter and exit the tank is through the vent. It is possible that water is condensing in the vent hose, and running back out the vent. I can't say. But no water is in the tank and it sits empty all winter outside in the North East.

 

[45Auto]

Re: Ethanol Fuel Seperation Problems

so my question is
where are the industry tests/research/experiments to prove or disprove all these different opinions.
And if water does form/leak into/come with the gas in boat fuel tanks why is not there a pump out line to the tank bottom?

This is such basic stuff that has been around for hundreds of years that there are not going to be any industry tests/research/experiments on it. Same reason you won't find any industry tests/research/experiments to prove or disprove that the earth is flat, or that 3 x 3 = 9.

There's not a pump out line on boats because it's not that big of a problem. An in-line fuel filter can usually easily handle it. Even if it is a problem, the worst consequence if your engine stops is that you have to get a buddy to tow you in or pay Sea-Tow a few hundred dollars. Airplanes have a drain because the consequences are much worse if their engine stops. The airplane pilots who don't drain their tanks are known as the "bold" airplane pilots. They are the inspiration for the old aviation saying, "There are old pilots and there are bold pilots, but there are NO old bold pilots!"

If condensation in the tank of your boat would kill you like it will in an airplane, your boat tank would be treated just like an airplane tank. It would have some kind of drain device on the bottom.

Obviously none of the posters doubting condensation have ever had even an introductory level basic thermodynamics course. Given volume, pressure, temperature and relative humidity you can calculate the dew point and at exactly what temperature condensation will form. My guess would be that if you calculate it for the north east, you wouldn't get condensation. Calculate it for New Orleans or Florida where the humidity is twice as high and you might find a different result. Last time I had to do a thermo calculation was in 1981, I don't need to dig all that stuff up again! Much easier just to go look in my tank that has been sitting there for a year.

The problem below, 8.137, is from an introductory level thermo book. It's a straight forward calculation on when condensation will begin in a tank. If you feel the need to do studies and analysises to verify these concepts, go for it!

If you want to doubt it exists because it hasn't happened in your tank, no big deal. The information is out there if you want to learn.

Airplane guys are very concerned about it because above about 10,000 feet the air temp is below freezing (ever wondered why that snow never melts off the high mountains in the summers?). A few ounces of water from condensation in your airplane gas tank once you're above 10,000' for a few minutes means that you now have a few blocks of ice in your tank waiting to clog your fuel intake or wreck your fuel pump. There's nothing like AAA for cars or Sea-Tow fo your boat you can call if your airplane engine quits.

A few ounces of water from condensation in your boat or car gas tank will get sucked straight through the engine and you'll never know it. Let your car or boat tank sit there long enough under the right conditions without running it and those few ounces at a time will build up to a substantial enough volume of water to affect your vehicle.

Firefighters worry about condensation in tanks because it makes crude oil tanks a bomb. It happens, it's a known thing (again, for over a hundred years), they deal with it. Burning fuel will burn down to the water level and instantly vaporize the water, creating a big explosion of burning fuel.

From the Los Angeles Fire Department Incident Management plan:

I spoke with an airplane mechanic this weekend about why airplanes have water in fuel problems.

Nothing wrong with speaking to someone who has had experience with the problem. Doesn't mean he has any idea about the cause of the problem.

Did you read the post from the Aviation Board I posted earlier? They're also worried about condensation in the ground storage tanks and fuel trucks. How many altitude cycles you think they go through?

Did you read the one from Shell on winterizing your aircraft for storage? Not too many altitude and pressure cycles on a winterized aircraft. It goes through the exact same conditions as a winterized boat.

From SumpThis, General Aviation. They even made a pretty little picture for it:

Fuel can also be contaminated from condensation that occurs within a fuel tank. Over a period of time, condensation could introduce a hazardous quanity of water.

To each his own. Some think they have condensation, some don't. Some think the world is round, some think the world is flat. Some think we went to the moon, some think we didn't. Lots of education available out there, up to you whether you choose to learn or not!

 

[edwardh1]

Re: Ethanol Fuel Seperation Problems

And yet another source, from another iboat forum :
As much as I love my Seaswirl, I recently found out about an issue know by local mechanics as the Seaswirl Syndrome. The issue relates to water getting into the gas tank through the instrumentation penetrations on the top of the tank. My boat is a Year 1999 and as the tank gets older the top of the tank starts to bow in allowing water to puddle right at the instrumentation penetrations. It eventually corrodes the bolting and breaks the gasket seal.

The fix, remove both the level assy and the fuel line assy clean the surfaces and the bolting. (keep the dirt out of the tank, I used a paint brush) and reseal using permatex #1. Only hand tighten the bolts until the sealer sets. Don't squeeze the sealant out when tightening. good luck