Fuel tank frustration

That sounds more reasonable. #12 MSG is .1046" thick so that puts me a
little over the minimum.

Stephen Baker wrote:
 > Glenn,
 > ABYC states a min. thickness for alu diesel tanks (5052, 5083, or 5086 alloy)
 > of 0.090", and all fittings should be 6061-T6 or 300-series stainless.
 > There is a lot more to the "recommendation", let me know if you want it.
 > Steve

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: <a style='text-decoration: underline;' href="http://www.rutuonline.com" target="_blank">http://www.rutuonline.com</a>
Shameless Commercial Division: <a style='text-decoration: underline;' href="http://www.spade-anchor-us.com" target="_blank">http://www.spade-anchor-us.com</a><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

By now you may have found the online articles about tank failures and 0.090"
walls, right? Big improvement if you go to 0.125". Number one reason for
failure on thin tanks is metal fatigue, especially at or near weldments.
Number one reason for failure on heavier tanks is corrosion. Number one
reason for corrosion is tank immersion (in water) or standing water on the
tank. If the tank is kept dry, ventilated, and built with 0.125" or thicker
walls and lid, then you've nixed 99% of the tank failure problems. Add
baffles, I think 20" to 30" apart? Stephen? What's the spec here? A
friend that builds tanks drills holes in the lid and sides, makes baffles
(lots of holes and limbers) with a bent over tab on top and both ends. He
welds the bent tabs to the tank through the holes, then fills the holes with
fill material. Grinds flush. Having baffles welded to lid and sides means
that regardless of tank mounting, that the lid-to-tank weldment is prevented
from fatigue failures since the baffles are doing double duty and
transferring load to the tank sides. He either glass beads or etches (can't
remember which) the whole tank, primers and paints. He doesn't use a
special anti-corrosion primer such as zinc chromate, but you could if you
want. The paint is some kind of epoxy paint. Ameron Devoe 229h I think
....industrial grade epoxy paint.

He puts the pick-up at the aft end, an inspection plate above that point,
sometimes a well (water and sludge collection) below that point. He uses
1-1/2" filler and a vent ...what was it? 5/8" or so? Can't remember. He
doesn't put sending units in the tank...FloScan instead. When my boat is
nearer being ready, I'll probably let him build me a tank ...

Brian

--
My boat project: <a style='text-decoration: underline;' href="http://www.advantagecomposites.com/tongass" target="_blank">http://www.advantagecomposites.com/tongass</a>


"Glenn Ashmore" <gashmore RemoveThis @mindspring.com> wrote in message
news:jcnjb.77205$sp2.22847@lakeread04...
 > That sounds more reasonable. #12 MSG is .1046" thick so that puts me a
 > little over the minimum.
 >
 > Stephen Baker wrote:
  > > Glenn,
  > > ABYC states a min. thickness for alu diesel tanks (5052, 5083, or 5086
alloy)
  > > of 0.090", and all fittings should be 6061-T6 or 300-series stainless.
  > > There is a lot more to the "recommendation", let me know if you want it.
  > > Steve
 >
 > --
 > Glenn Ashmore
 >
 > I'm building a 45' cutter in strip/composite. Watch my progress (or lack
<font color=purple> > there of) at: <a style='text-decoration: underline;' href="http://www.rutuonline.com</font" target="_blank">http://www.rutuonline.com</font</a>>
<font color=purple> > Shameless Commercial Division: <a style='text-decoration: underline;' href="http://www.spade-anchor-us.com</font" target="_blank">http://www.spade-anchor-us.com</font</a>>
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

I picked up on most of that already. It was the thickness that had me
flustered. You are right that .125" would be much better. Easier to
get good welds on too. Baffels are required every 30" and rosette welds
are what those filled holes are called. Fillers must be a minimum of 1
1/2" and vents 5/8". Those things I expected.

Other things I found that I was not expecting: 46 CFR 183.518 for small
passenter vessels says ALL fittings must be on top. 46 CFR 58.10-10(a4)
allows cleanout plugs and supply outlets on the bottom of the tank.

What has me really confused is the relationship between 33 CFR 181 - 183
and 46 CFR. They are not easy to figure out in the first place and the
way they are presented on the web makes it a lot worse.

SAFETY STANDARDS FOR BACKYARD BOAT BUILDERS has nothing in it that
applies to diesel powered vessels over 20'. I guess I will have to
spring for the ABYC guides but from what I have seen so far they don't
track exactly with the CFRs either.

Brian D wrote:
 > By now you may have found the online articles about tank failures and 0.090"
 > walls, right? Big improvement if you go to 0.125". Number one reason for
 > failure on thin tanks is metal fatigue, especially at or near weldments.
 > Number one reason for failure on heavier tanks is corrosion. Number one
 > reason for corrosion is tank immersion (in water) or standing water on the
 > tank. If the tank is kept dry, ventilated, and built with 0.125" or thicker
 > walls and lid, then you've nixed 99% of the tank failure problems. Add
 > baffles, I think 20" to 30" apart? Stephen? What's the spec here? A
 > friend that builds tanks drills holes in the lid and sides, makes baffles
 > (lots of holes and limbers) with a bent over tab on top and both ends. He
 > welds the bent tabs to the tank through the holes, then fills the holes with
 > fill material. Grinds flush. Having baffles welded to lid and sides means
 > that regardless of tank mounting, that the lid-to-tank weldment is prevented
 > from fatigue failures since the baffles are doing double duty and
 > transferring load to the tank sides. He either glass beads or etches (can't
 > remember which) the whole tank, primers and paints. He doesn't use a
 > special anti-corrosion primer such as zinc chromate, but you could if you
 > want. The paint is some kind of epoxy paint. Ameron Devoe 229h I think
 > ...industrial grade epoxy paint.
 >
 > He puts the pick-up at the aft end, an inspection plate above that point,
 > sometimes a well (water and sludge collection) below that point. He uses
 > 1-1/2" filler and a vent ...what was it? 5/8" or so? Can't remember. He
 > doesn't put sending units in the tank...FloScan instead. When my boat is
 > nearer being ready, I'll probably let him build me a tank ...
 >
 > Brian
 >

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: <a style='text-decoration: underline;' href="http://www.rutuonline.com" target="_blank">http://www.rutuonline.com</a>
Shameless Commercial Division: <a style='text-decoration: underline;' href="http://www.spade-anchor-us.com" target="_blank">http://www.spade-anchor-us.com</a><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

Don't forget that Subchapter K (the 46CFR passages) are for vessels
carrying passengers for hire. Their rules are much stricter than
those for rec. vessels, presumably because recreational vessels are
used more "voluntarily." Subchapater K covers vessels up to 100 tons,
so they are not really thinking of 40-gal fuel tanks.

ABYC publishes a book that puts together in one place all the federal
regs for recreational boats -- a good thing to have.

Cheers,
Michael Porter




Glenn Ashmore <gashmore.DeleteThis@mindspring.com> wrote:

<snip>
 >
 >What has me really confused is the relationship between 33 CFR 181 - 183
 >and 46 CFR. They are not easy to figure out in the first place and the
 >way they are presented on the web makes it a lot worse.
 >
 >SAFETY STANDARDS FOR BACKYARD BOAT BUILDERS has nothing in it that
 >applies to diesel powered vessels over 20'. I guess I will have to
 >spring for the ABYC guides but from what I have seen so far they don't
 >track exactly with the CFRs either.
 >

Michael Porter Naval Architect / Boatbuilder
mporter at mp-marine dot com
<a style='text-decoration: underline;' href="http://www.mp-marine.com" target="_blank">www.mp-marine.com</a><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

Brian D says:

 > Add
 >baffles, I think 20" to 30" apart? Stephen? What's the spec here?

No spec listed, but 30" or so is reasonable. The other thing to make sure of
with baffles is that the size of the holes does not exceed 25-30% of the
cross-section area.
On alu tanks, I would recommend as little plug-welding as possible, say limited
to the top surface. (i.e. build the tank without the top, then insert baffles,
then close) Each plug becomes a hard point, albeit small.

Steve<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

I had my aluminum gasoline tanks built by Ezell Industries one of the three
marine tank builders in Perry Fl. I let them decide where the baffles were
( a wise move) also they provided the tank fitting and valves which some of
need to be al. rather than ss or brass. One thing to consider also is the
pickup tubes, they made these with nylon? tubing swaged onto the al tank top
fittings. Some other people I talked to were not up to speed on the issue of
not using metal pickup tubes as they are subject to vibration and fatigue.
Wouldn't want the pickup to break!!! I was very happy with Ezell and the
good work they did.
Then Painting, which I did. This system is my standard and I use it on any
alum. thing I make for boats.
1, clean with acid ectching solution ( like, Ditzler DX533)
2 prime with dupont Variprime 615S self etching primer.
3 finish with several coats of 2 part epoxy primer.
For exposed alum. things, add about three finish coats of a urethane
enhanced enamel like Limco 1234.
All of the products are availble from automotive distributers I think the
key is using the variprime as is bonds to aluminum like nothing else I know
of..

--
Ron White
My boatbuilding website is:
www.concentric.net/~knotreel
 >> Stay informed about: Fuel tank frustration 

I am beginning to wonder if locally built aluminum tanks are a good
idea. Every shop around here is tooled up for 6061 but marine tanks
need to be 5000 series. I will have to supply my own 5086 and TIG
welding rod and the best price I can find is in New Orleans. $130 a
4x10 sheet plus about $100 shipping. Still, a lot better than $300 a
sheet in Atlanta but not as good as $65/sheet for 1018 mild steel locally.

If I go with aluminum I think I will have to machine my own fittings.
There are very few sources of 5000 series aluminum fittings and the
selection is limited. It will be fairly simple to mill and tap some
NPTF fittings from 1" round for welding onto the tank.

I would like to hear some discussion of mild steel vs aluminum. Total
cost of mild steel tanks is about half that of aluminum but weighs about
twice as much. In this case a pair of custom 40 gallon would cost $600
in aluminum with some effort on my part to get the alloy vs $320 for
mild steel and weigh 72 pounds vs 125 for steel. From what I hear, a
well painted and installed steel tank will last just as long as
aluminum. Longer if the aluminum is not properly installed.

Ron White wrote:

 > I had my aluminum gasoline tanks built by Ezell Industries one of the three
 > marine tank builders in Perry Fl. I let them decide where the baffles were
 > ( a wise move) also they provided the tank fitting and valves which some of
 > need to be al. rather than ss or brass. One thing to consider also is the
 > pickup tubes, they made these with nylon? tubing swaged onto the al tank top
 > fittings. Some other people I talked to were not up to speed on the issue of
 > not using metal pickup tubes as they are subject to vibration and fatigue.
 > Wouldn't want the pickup to break!!! I was very happy with Ezell and the
 > good work they did.
 > Then Painting, which I did. This system is my standard and I use it on any
 > alum. thing I make for boats.
 > 1, clean with acid ectching solution ( like, Ditzler DX533)
 > 2 prime with dupont Variprime 615S self etching primer.
 > 3 finish with several coats of 2 part epoxy primer.
 > For exposed alum. things, add about three finish coats of a urethane
 > enhanced enamel like Limco 1234.
 > All of the products are availble from automotive distributers I think the
 > key is using the variprime as is bonds to aluminum like nothing else I know
 > of..
 >

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: <a style='text-decoration: underline;' href="http://www.rutuonline.com" target="_blank">http://www.rutuonline.com</a>
Shameless Commercial Division: <a style='text-decoration: underline;' href="http://www.spade-anchor-us.com" target="_blank">http://www.spade-anchor-us.com</a><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

Glenn Ashmore wrote:
 > I am beginning to wonder if locally built aluminum tanks are a good
 > idea. Every shop around here is tooled up for 6061 but marine tanks
 > need to be 5000 series. I will have to supply my own 5086 and TIG
 > welding rod and the best price I can find is in New Orleans. $130 a
 > 4x10 sheet plus about $100 shipping. Still, a lot better than $300 a
 > sheet in Atlanta but not as good as $65/sheet for 1018 mild steel locally.
 >
 > If I go with aluminum I think I will have to machine my own fittings.
 > There are very few sources of 5000 series aluminum fittings and the
 > selection is limited. It will be fairly simple to mill and tap some
 > NPTF fittings from 1" round for welding onto the tank.
 >
 > I would like to hear some discussion of mild steel vs aluminum. Total
 > cost of mild steel tanks is about half that of aluminum but weighs about
 > twice as much. In this case a pair of custom 40 gallon would cost $600
 > in aluminum with some effort on my part to get the alloy vs $320 for
 > mild steel and weigh 72 pounds vs 125 for steel. From what I hear, a
 > well painted and installed steel tank will last just as long as
 > aluminum. Longer if the aluminum is not properly installed.
 >
 > Ron White wrote:
 >
  >> I had my aluminum gasoline tanks built by Ezell Industries one of the
  >> three
  >> marine tank builders in Perry Fl. I let them decide where the baffles
  >> were
  >> ( a wise move) also they provided the tank fitting and valves which
  >> some of
  >> need to be al. rather than ss or brass. One thing to consider also is the
  >> pickup tubes, they made these with nylon? tubing swaged onto the al
  >> tank top
  >> fittings. Some other people I talked to were not up to speed on the
  >> issue of
  >> not using metal pickup tubes as they are subject to vibration and
  >> fatigue.
  >> Wouldn't want the pickup to break!!! I was very happy with Ezell and the
  >> good work they did.
  >> Then Painting, which I did. This system is my standard and I use it on
  >> any
  >> alum. thing I make for boats.
  >> 1, clean with acid ectching solution ( like, Ditzler DX533)
  >> 2 prime with dupont Variprime 615S self etching primer.
  >> 3 finish with several coats of 2 part epoxy primer.
  >> For exposed alum. things, add about three finish coats of a urethane
  >> enhanced enamel like Limco 1234.
  >> All of the products are availble from automotive distributers I think the
  >> key is using the variprime as is bonds to aluminum like nothing else I
  >> know
  >> of..
  >>
 >

Either aluminum or steel will probably outlast both you and me. I've
seen diesel tanks for equipment on trucks made from steel that have
never been painted that were over 30 years old. I'm thinking about
making mine out of steel, but I plan on some type of coating inside and
out, just not sure what brand yet. Weight is no problem for me with a
steel boat and no plans for racing, just cruising. I would think that
would be a major deciding factor for you. Can you stand the weight.
Cost is always a major deciding factor for me. I have to build on the
cheap. I would think you would have more resources available. Is $300
or $400 a deciding factor? What about a poly tank? I'm sure you've
priced those, about the same as aluminum, but they're ready built.

Good Luck,

Donald

--
I'm building a Steel Robert's 434. You can sneak a peek if you wish by
clicking on me link below.
<a style='text-decoration: underline;' href="http://bellsouthpwp.net/d/o/donrayp/" target="_blank">http://bellsouthpwp.net/d/o/donrayp/</a>
'USA, Home of the best
politicians money can buy'<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

Steve,

I've seen tanks made the way you suggested, but with the tank top oversize
so it extended an additional inch-plus on either side. This was for
suspending the tank by the lip. With all the pounding that a boat goes
through, I feel concern that the top weldment would be prone to fatigue and
cracking. OTOH, I do know lots of people do it this way (1/8" sides/bottom,
3/16" top). What do you think?

Brian


"Stephen Baker" <saildesign.RemoveThis@aol.comnospam> wrote in message
news:20031016072745.10402.00001165@mb-m14.aol.com...
 > Brian D says:
 >
  > > Add
  > >baffles, I think 20" to 30" apart? Stephen? What's the spec here?
 >
 > No spec listed, but 30" or so is reasonable. The other thing to make sure
of
 > with baffles is that the size of the holes does not exceed 25-30% of the
 > cross-section area.
 > On alu tanks, I would recommend as little plug-welding as possible, say
limited
 > to the top surface. (i.e. build the tank without the top, then insert
baffles,
 > then close) Each plug becomes a hard point, albeit small.
 >
 > Steve<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

Donald Phillips wrote:

 > Either aluminum or steel will probably outlast both you and me. I've
 > seen diesel tanks for equipment on trucks made from steel that have
 > never been painted that were over 30 years old. I'm thinking about
 > making mine out of steel, but I plan on some type of coating inside and
 > out, just not sure what brand yet. Weight is no problem for me with a
 > steel boat and no plans for racing, just cruising. I would think that
 > would be a major deciding factor for you. Can you stand the weight.
 > Cost is always a major deciding factor for me. I have to build on the
 > cheap. I would think you would have more resources available. Is $300
 > or $400 a deciding factor? What about a poly tank? I'm sure you've
 > priced those, about the same as aluminum, but they're ready built.

I don't think interior coatings on diesel tanks are a good idea. Diesel
is not going to attack the metal and is a pretty good corrosion
preventive. Any coating carries the possibility of flaking off and
finding its way into the filters.

$300 would not be a deciding factor but now that I am on the down hill
side of the project I find Everett Dirksen's comment about "A billion
here, a billion there, pretty soon we are talking real money."
particularly relevent.

I checked every maker of poly tanks but could not find a shape that
would work without wasting a lot of space or leaving the COG of the fuel
way to high and getting molds made for custom tanks is way to expensive.

I considered building my own out of glass/epoxy but I don't like the
risk. I built two water tanks and found it took a lot of effort to get
really solid laminations in the corners. If there is even one pin hole
there will be some weeping. I can live with a little fresh water
weeping but not diesel.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: <a style='text-decoration: underline;' href="http://www.rutuonline.com" target="_blank">http://www.rutuonline.com</a>
Shameless Commercial Division: <a style='text-decoration: underline;' href="http://www.spade-anchor-us.com" target="_blank">http://www.spade-anchor-us.com</a><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

Did you check Ronco for a tank? They make more stock shapes than anyone I
know, and are very easy to work with. <a style='text-decoration: underline;' href="http://www.ronco-plastics.com/." target="_blank">http://www.ronco-plastics.com/.</a>

I'd stick with regular steel for the tanks if you can't find one at Ronco. I
have a pair that are 17 yrs. old and fine. You are right about the inside,
the diesel is a good anticorrosion treatment, as long as you keep the water
out. The outside should be painted with a good coating of some kind, and the
bottom should be supported so that air can circulate under it. Obviously,
you've got to keep the water off the top of the tank as well. Be sure to
have the maker put a sump with a dip tube from the top in the tank so you
can suck out any water that might end up in there.

"Glenn Ashmore" <gashmore.RemoveThis@mindspring.com> wrote in message
news:EoRjb.78877$sp2.14422@lakeread04...
 >
 > Donald Phillips wrote:
 >
  > > Either aluminum or steel will probably outlast both you and me. I've
  > > seen diesel tanks for equipment on trucks made from steel that have
  > > never been painted that were over 30 years old. I'm thinking about
  > > making mine out of steel, but I plan on some type of coating inside and
  > > out, just not sure what brand yet. Weight is no problem for me with a
  > > steel boat and no plans for racing, just cruising. I would think that
  > > would be a major deciding factor for you. Can you stand the weight.
  > > Cost is always a major deciding factor for me. I have to build on the
  > > cheap. I would think you would have more resources available. Is $300
  > > or $400 a deciding factor? What about a poly tank? I'm sure you've
  > > priced those, about the same as aluminum, but they're ready built.
 >
 > I don't think interior coatings on diesel tanks are a good idea. Diesel
 > is not going to attack the metal and is a pretty good corrosion
 > preventive. Any coating carries the possibility of flaking off and
 > finding its way into the filters.
 >
 > $300 would not be a deciding factor but now that I am on the down hill
 > side of the project I find Everett Dirksen's comment about "A billion
 > here, a billion there, pretty soon we are talking real money."
 > particularly relevent.
 >
 > I checked every maker of poly tanks but could not find a shape that
 > would work without wasting a lot of space or leaving the COG of the fuel
 > way to high and getting molds made for custom tanks is way to expensive.
 >
 > I considered building my own out of glass/epoxy but I don't like the
 > risk. I built two water tanks and found it took a lot of effort to get
 > really solid laminations in the corners. If there is even one pin hole
 > there will be some weeping. I can live with a little fresh water
 > weeping but not diesel.
 >
 > --
 > Glenn Ashmore
 >
 > I'm building a 45' cutter in strip/composite. Watch my progress (or lack
<font color=purple> > there of) at: <a style='text-decoration: underline;' href="http://www.rutuonline.com</font" target="_blank">http://www.rutuonline.com</font</a>>
<font color=purple> > Shameless Commercial Division: <a style='text-decoration: underline;' href="http://www.spade-anchor-us.com</font" target="_blank">http://www.spade-anchor-us.com</font</a>>
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

Keith wrote:
 > Did you check Ronco for a tank? They make more stock shapes than anyone I
<font color=purple> > know, and are very easy to work with. <a style='text-decoration: underline;' href="http://www.ronco-plastics.com/.</font" target="_blank">http://www.ronco-plastics.com/.</font</a>>

My holding tanks are Roncos. No question that Ronco has the best
selection and best quality but the last time I checked they only build
water and holding tanks. HDPE is fine for water and holding but not for
diesel. They do use cross linked PE in their industrial chemical line
but for some reason they don't want to use it in their marine line.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: <a style='text-decoration: underline;' href="http://www.rutuonline.com" target="_blank">http://www.rutuonline.com</a>
Shameless Commercial Division: <a style='text-decoration: underline;' href="http://www.spade-anchor-us.com" target="_blank">http://www.spade-anchor-us.com</a><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration 

Brian says:

 > I've seen tanks made the way you suggested, but with the tank top oversize
 >so it extended an additional inch-plus on either side. This was for
 >suspending the tank by the lip. With all the pounding that a boat goes
 >through, I feel concern that the top weldment would be prone to fatigue and
 >cracking.
 > OTOH, I do know lots of people do it this way (1/8" sides/bottom,
 >3/16" top). What do you think?
 >

I'm not exactly fond of that method. As you say, too risky. If you want to
hang something make up a bracket properly sized, and then all you have to
replace is the bracket if it fails. THat's the same reason why my stereo
system is component rather than "boom-box" style. I don't have to replace
everything coz the turntable dies (yes, I'm that old )

I love things that work, and can be depended on. That includes gravity. If
gravity will hold something in place when static, then a simple strap to take
care of the dynamic situation is all you need. And it's cheap!

Steve<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Fuel tank frustration