On Nov 16, 1:29*pm, "Roger Long" wrote:
"Capt. JG" wrote



No... didn't miss it. He's dealing with bio/water issues every day. I
think I'll trust his experience, although he didn't say to be obsessive
about it. He's advocating exactly that... minimizing the surface area.

But he's missing out on the frequent opportunity to have the sloshing of a
partially full fuel tank knock off some bio film sticking to the sides.
He's also increasing the average age of the fuel with its absorbed water
content and oxidation. *I've been working with commercial boat operators for
nearly four decades and never heard of trying to keep fuel tanks topped up
until this newsgroup.

The yard manager I brought my non-running engine to when the boat arrived in
Portland had similar or more experience. *He successfully diagnosed that all
it needed was a thorough cleaning after the Yamaha shop and dealer in MI
told me it needed two new injectors and possibly an injector pump. * The
engine has been running perfectly for three seasons on those components.
That gives him a lot of street cred in my book. His position on fuel was
that you should use up as much as you can before refueling so that most of
what you are burning is as fresh as possible. *Why do experienced people
differ on points like this? Because it doesn't make much difference.
Topping off might make sense for the once a month weekender but would be
crazy for the almost daily sailor such as myself whether it was going to the
fuel dock and standing in line, doing the docking and undocking, etc., for a
gallon or lugging a can all the way down the dock at the end of the sailing
day when tired guests want to get home. *The fuel sitting in that can is as
likely to go bad as what is in the tank. *Do you keep topping up the can
that you top up the tank with? *Where does it end?

What micron sizing do you use for the primary and secondary?

The Racor primary is 2 Mu because the polishing system keeps much crud from
every reaching it and it is oversized for the engine so there is no downside
to the finer element. *It's pressure fed by the electric fuel pump.

The secondary is a Yamaha engine mounted filter and probably 10 Mu. *Since
only their elements fit, I have to buy whatever they supply for the engine
anyway.

The polishing filter is 10 Mu but, as Rich H points out, will take out
smaller stuff because the fuel goes through it many times and it is a depth
filter instead of a surface filter. *It also gets finer as it loads up.

--
Roger Long

I tend to keep my day tanks topped up and clean. with just under
10,000 gal in the main tanks we simply filter as we dispence to the
small boats or our day tanks. we filter when we fill so we dont get a
bug problem from the fuel barges or docks. but that on a boat with
lots of fuel.

Roger

Glad you noted the crud in the bottom of the Shelco housing.... this
debris is/are the nucleation sites upon which such particle grow/
agglomerate.
Full or topped-off tanks - never unless Im travelling. Water in oil
is in two phases: 1. sensible (free) water that drops out by gravity,
2. water that is emusified (bound) in the oil.
Fuel oil that is long term exposed to atmosphere saturated with water
(from vapor) will eventually settle out in the bottom of the tank. I
never ever 'top off' a tank unless I plan to use most of it in the
short term. Why store the oil in a tank with an atmospheric vent only
to have it uptake water (vapor), etc.? Simple solution is only upload
what you need plus some reserve; if storing long term, drain the oil
and burn it in your home heater as EMPTY tanks dont 'condense'
water.

The probable chief organism that thrives in fuel oil tanks is
Cladosporium Resinae - ***a fungus*** that is spread by spores ...
most probably aspirated through the tank VENT pipe. Currently Im
using a bio-blocking 0,2µM abs PTFE membrane filter capsule on my vent
and will compare the tank innards on my next scheduled clean-out (in 2
years). Million gallon field fuel tanks rarely become contaminated;
its the teeny boat tanks that usually have the particulate/
contamination problems.

Im currently travelling and using a lot of fuel so Ive temporarily
removed the desiccant vapor trap on the vent line.

regards to all.

"RichH" wrote

Why store the oil in a tank with an atmospheric vent only to have it uptake
water (vapor), etc.?

Exactly.

Please confirm that I'm correct in the advice to others (some outside the
newsgroup) that there is no point in filling the tank unless it's filled up
into the vent so that the surface area of fuel available for water vapor
transfer is the cross section of the vent pipe and not the whole top of the
tank.

Since this is impractical in many vessels and impractical in most normal
operation, the whole topping up the tank thing is a crock.

I'm going to put a desiccant vapor trap on my sounding tube for the winter
which is easy to do and tape over the vent.

--
Roger Long

Please confirm that I'm correct in the advice to others (some outside the
newsgroup) that there is no point in filling the tank unless it's filled up
into the vent so that the surface area of fuel available for water vapor
transfer is the cross section of the vent pipe and not the whole top of the
tank.

Since this is impractical in many vessels and impractical in most normal
operation, the whole topping up the tank thing is a crock.

I'm going to put a desiccant vapor trap on my sounding tube for the winter
which is easy to do and tape over the vent.

--
Roger Long

Here's a website that gives a brief tech description of what is
happening .... sorry that its JetFuel but the same happens with
diesel, etc.:
http://www.flowmeterdirectory.com/fl..._07082401.html

My professional (filtration engineering) work in this area has
included the ultra-pure ultra-dehydrated oils used in high voltage
transformers, contactors and tap changers ... although sealed,
eventually become contaminated with water (free, dissolved and
emuslified) which radically changes the dielectric strength of the
oil. The water uptake is all by 'chemical equilibrium'; you put in
ultra-dehydrated oil - come back in 2-3 years and remove the water
( or replace the equipment if if shorts out due to the water and
generated particles). Simple physical-chemical equilibrium at work.

Bruce reported using oil that was barreled in WWII. Entirely possible
if the barrel was filled at temperature that sterilized the contents,
is totally sealed, no water entered, and no fungal spores got in.
After all, that oil is zillions of years old and it stayed in the
ground because no microorganism used it as a nutrient source, etc.