New Diesel Tank

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Between the battens and the tank
will be 3/4" thick Buna N Rubber bars.
To account for that, I screwed some 3/4" thick plywood onto the bottom of the old tank.

This way I can set the old tank on top of the battens and the spacing will be correct.
It also forced the warped bottom
of the old tank back into plane.

I spent a few hours measuring and tweaking the supports, because
it can't sit too high.

If it's not perfect,
I won't be able to fit the steering back in.

That would be a bummer.

January 2006 --

No this isn't the new tank!

I hauled the old one back to the boat to help make braces for the new tank.
Since the old tank was sunk in foam, it was tough to figure out how to make the braces fit just right. I measured the heck out of the old foam before removing it, but wasn't confident that I could build braces based on those measurements.

Having the old tank as a guide should make them fit perfectly.

The tank will sit on these fiberglass battens, which will be epoxied to the hull. The challenge is that the hull is curved
in a pretty wacky way. (It's a boat.)

I used Play-Doh to stick the battens against the hull.

(Not recommended for under the waterline.)

The idea is that I can pop it off, wash it and redo it if I screw it up the first time.

I don't know
if this is going to work, and I want to back out easily.

Here, the battens are in place. I took my best guess as to how far off the hull they'd be, and added an inch. So the long batten is sitting about an inch and a half up, and the short forward one is about two inches off the hull.

When the tank is set into place on top of them, it'll mush the Play-Doh down and the battens will be right up against the plywood spacer.

Then I can go back and fill the gap between the batten and the hull with epoxy putty.

It was tough to move the old tank into place directly over the battens, then drop it in.

I didn't want to slide it around, because that might mess up the battens.

I wonder how long it takes Play-Doh to cure.

It will be really interesting to pull the tank back out and see if this worked.

Holy cow.

It worked.

I can place this straight edge
across the battens at any angle,
and it's flush. The battens shifted a bit when I set the old tank down, (note the offset from the red lines,) but I'm not going to do it over.
I'll just have to spend the rest of my life knowing that my fuel tank supports aren't perfectly aligned.

Oh gosh. (Grin)

Note that Play-Doh cracks and shrinks a *lot* when it dries out.
I researched this on the internet (after I'd done the deed)
so I didn't wait for it
to dry completely .

There was more room under the battens than I'd anticipated. Although I had measured the depth of the old polyurethane foam packing, the measurements only matched along the edges. I think that over the last 25 years, the weight of the full tank had crushed the foam in the center areas, letting the tank sag.

This one is very high.

I could have used a thicker batten.

I'll just have to fill the space in with little blocks of FRP and epoxy them into place. Trying to fill it entirely with epoxy would take forever and it would probably kick off hot
and get brittle.

I injected a super thick epoxy putty under the ends, to glue the battens into place.

When it's secure, I can go back and remove the Play-Doh.

With the epoxy cured,
I pulled out the Play-Doh and gave everything
a good scrub, then let it dry for a week.

Here are some scrap pieces of prefab FRP,
trial fit into place. These should let me pack under the battens with epoxy without fear of having it kick off with a "critical mass" and start smoking
and getting all bubbly and brittle.

I made a super thick putty of West System epoxy, fiberglass chop from Tap Plastics,
and colloidal silica. I figure the fiberglass chop
will make it a little stronger. The putty was just mashed in there really well with my fingers, making sure there weren't any voids around the little blocks.

It's evening, and the temperature is in the low 50F range, plus the hull is sitting in 55 degree water.
That helped keep the epoxy from kicking off too fast.
I went through about 50 pairs of latex gloves.

Finally, I put nice big fillets of epoxy putty along the sides, and rolled a three inch strip of Knytex tape over it.

The fiberglass really isn't necessary from a structural perspective, but it helped to keep the putty in place and let me smooth the area down so that there won't be a rough surface requiring sanding.

Obviously there's some grinding in store once the epoxy cures, but I don't want to have to deal with a bunch of little nooks and crannies with needle-sharp peaks of epoxy.

The New Tank arrived from
Florida Marine Tanks
They built the original tank, and this one was built to the original drawings,
but with thicker metal.

I'm pleased with the tank,
but wasn't pleased with the paint.
I had considered asking them to leave the paint off, but stayed quiet thinking that they did this for a living, and
maybe they knew what they were doing.

However, the tank was scratched up when it arrived, and I decided to wash it and touch up the spots where paint had been scratched, so the scratches wouldn't start corroding. To my amazement,
the paint started to come off with a
solution of Simple Green and Water,
scrubbed with a teflon-safe kitchen pad.

I took a garden hose and started blasting it,
and the paint started to peel off.
This was a shock.

If it can't handle a good hosing,
it sure isn't going to last long in my boat.

I should have let Roy weld it up locally. Oh well. Too late now.

It was very clear that no attempt had been made to clean off any manufacturing residue before painting.

Aluminum is difficult to paint in the best of conditions, and to paint it well
requires effort.

I had not expected perfection,
but had hoped that a minimal effort would have been expended on a proper job,
and I was prepared to live with the manufacturer's best effort.

But this is totally unacceptable, so I stripped it down and did it over.

I started out with a low-end stripper,
which did a fine job on this weak paint.
But I was in a hurry, so broke out the Jabsco. After one round of Jabsco, which took off most of the paint, I washed it really well and then
went back with the weaker stripper
to pick up any leftover fragments.
The second stripper run also made sure that
no Jabsco residue remained.

I used a nylon stripping brush on all the welds,
to get them super clean. The rest of the tank was scrubbed with a nylon 3M Stripping scrubber, which scuffed up the tank and exposed new metal.

I spent about three hours getting it totally clean.

While the tank was still wet and shiny, it was seriously bathed in Alumiprep, which is primarily a Phosphoric Acid etching solution. It turned the metal nice and white, and foamed up a bit wherever it found oxidation.

Aluminum will oxidize in minutes, which is why it's so hard to paint. The oxidation layer prevents paint from adhering. This stuff
removes the oxidation.

The second bath was Alodine, which is primarily a Chromic Acid solution. This stuff chemically bonds with the surface metal and seals it, preventing oxidation from forming.

I let it sit for five minutes, brushing more on over and over to keep it wet. It turns the metal red.

Then I hosed it down well.

When it was dry, I painted the bottom with Interlux Interprotect 2000E.
I had some in the garage, left over from my last haulout, and Interlux technical support said it would still be good after two years
unless it had been frozen.

This stuff is a serious two part epoxy barrier coat, used to prevent water penetration into the hull.
It also is a great metal primer.

The 3M stripping pad left a very rough surface, and I'm positive that this stuff will stay on. The surface was so ready, even the blue masking tape didn't want to come off
after only a few hours.

I should mention that this is probably overkill. What the heck.
The tank is going to start corroding from the inside, as soon as a little water gets in.
However, it will take many, many years to corrode through from the inside,
and with proper maintenance it may *never* corrode through.
Since the tank sits near the bottom of the boat, and water can run under it to get to the bilge,
it will get wet occasionally. Heck, it's a boat, of *course* it's going to get wet.
I want to be able to hose down my entire engine area and keep it clean.
If I can minimize the potential for corrosion to start on the outside of the tank, that's a good thing.

Some folks have gone so far as to take a 3M Pad and scrub the paint *into* the surface of the metal, so that the paint will adhere to new metal that has never been exposed to air. I thought about it,
but really feel that I had already prepared a perfect surface. Three hours with a stripping pad,
plus the Alumiprep and Alodine steps, should be above and beyond what's necessary.

(If I had left the metal bare, I would have needed to polish it up well. Corrosion starts in the scratches.)

Continuing the theme
of massive over-engineering,
I primed the top half of the tank with
Petit two part metal primer.

This is a serious chemical soup.

It is "self etching", which
isn't really necessary at this point.
However, it should catch any little areas of metal that didn't get a full treatment the first time around.

The Petit primer is very thin,
and requires no sanding before putting on the finish coats.

There were some drips.
I didn't want to roll it, because it's thin enough to splatter all over the place. I also didn't tape off the bottom, because the Interprotect 2000E is still green and I didn't know how
it would handle tape.

However, making it pretty isn't really one of my objectives.
In fact there some serious sags in the Interprotect part, too.
Who cares? When it's installed, the only visible part
will be the top and
eight inches in the front.

I did take special care
to make sure all the welds
were well primed.

Corrosion starts in crevices.

You can see that it dries very thin,
even if it looks too thick going on.

This looks kinda Gothic, huh?
Cool picture.

Finally, the whole top was sprayed with six coats of Rust-O-Leum.

I went with yellow, for Diesel, just to brighten things up down there.

Heck, the bottom of the boat will be Gray, the new engine is Gray, and
I thought the new Fuel Tank
ought to have a little color.

Interior design is such a challenge.

I thought about making it Mauve,
or some other really weird color,
but decided that the tank would probably outlast the joke.
(Remember Avocado refrigerators?)

I don't know why I did this,
but it's done.

It was just so yellow.


Note the
New Limber Holes.

The front bulkhead on the left side of this picture is drying out (you can see one of the heat lamps) and I'm going to inject it with penetrating epoxy before painting it.

Also, I want to finish everything aft of the tank, before putting the new tank in, so that I don't have to
crawl over it.

I had to cut a big notch out of this non-structural bulkhead in order to remove the old fuel tank,
and I'm not going to glass the section back in.

Instead, I'm going to bolt this fiberglass angle iron across the front and top. It's made from prefab FRP from
McMaster-Carr, cut to size and painted.

Once the new fuel tank is installed, the inside of that compartment will be inaccessible, so the bolt needs to be totally secure. I'm using these 5/16 inch
"perforated base" studs, made of 316 stainless.

The bulkhead was lightly scored with a hole saw as a guide, and then a little bit of laminate was removed with my Handy Dremel Tool.

The stud was set with super thick epoxy putty,
with a
little swatch of fabric over
the top.

That should hold it.

Before gluing them down, the bars were scrubbed well with Simple Green and a green 3M pad, to remove excess powder from the manufacturing process.

Then both surfaces were painted with glue, and when it was tacky they were stuck together. The weight of the tank will hold them secure, I'm sure, but this will keep them from moving until the tank is in place.

One big bar would have worked, too, but I'd originally planned on making smaller supports, and so had purchased 3/4" x 3/4" rubber bars. This will work out just as well, though, as air can get down the slot between the bars and keep the area dry. (I hope.)

The tank will sit on a bed of 3/4" thick Buna-N Rubber bars. To hold them in place, I glued then down with 3M Scotch-Grip 1300 Contact Cement.

Those steel studs sticking out the front had been taped over, and the tape was covered with epoxy and paint.

Fortunately there was so much stuff on the tape that it was solid, and a good twist with a vice grip pliers just snapped the epoxy, and the whole think just unscrewed from the stud. Whew.

To provide support for the front of the tank, I glued more
Buna N Rubber right in the middle of the fiberglass beam, where bulkhead is cut.

I had a 1-1/4" bar,
but it wasn't big enough so I
layered it with another
1/4" section of rubber.

This keeps the tank
from moving forward.

Then the new tank was carefully set into place and the support bolted down.

I attached the fill hose and vent, and filled the tank up. Hooray.

I want the tank full, to compress those rubber bars underneath.
They're pretty hard rubber, but they'll compress a little bit and I want them at full compression before installing the tie-down straps across the top.

Ready for
the tank!

Gee, all that work and I'm never going to see this again, ever.

ever, ever,
ever, ever

I'm so sad. (grin)

The 304 Stainless tie-down straps are through bolted in the back (you can see in the upper left) and folded back out of the way.

I had two fuel feeds installed.

The one in the back is the normal one, and picks up fuel a few inches
from the bottom of the tank.

The one in the front is a "clean out" pipe, which pulls from the lowest point in the tank. Whenever I feel like it, I can pull fuel out of the tank, run it through the Racor filter, and dump it back in the tank. This should help prevent clogs in the main fuel feed.

I suppose it could also be used like a "reserve" switch to get an extra 15 minutes of run time if I get stupid
and run out of diesel.

I'm pulling all new hoses, of course.

There's no point doing this halfway. (grin)

In this picture, the old vent hose is stuck on there, just to keep fuel from splashing out until I put the new hose on.

You can also see the old ground wire. ABYC standards require that the deck fill be grounded to the tank. After taking a good look at the old wire, I decided to replace it with a new yellow one.

What the heck, might as well.

Here's the return fitting.

I'm a little annoyed with it, since there isn't room to install anything but a single nipple.

I'll need to have two feeds coming into this:
One from the engine, and the other from the
fuel distribution panel
. However, putting a brass extension on this would create leverage that could bend or break something, since the fittings would be hanging over the edge of the tank. I'll have to tee the engine return into this hose up closer to the engine.

The tank is held down with 304 Stainless straps, from McMaster-Carr.

In the back, they're through bolted to the bulkhead, but in front they're bolted with 1" lag bolts. Since the holes go through into the bulkhead, I stuck a dab of Lifecalk in there before installing the bolts.

The tank is protected from scratches with a pad
of Buna N rubber.

When I bought the boat, the Racor was mounted in a tough spot down low, on the left side of the engine room.

I've always had a Walbro electric fuel pump, and it was mounted up high on the right side of the engine room.

So I had hoses running
all over the place.

That is now all consolidated into a single Fuel Distribution Panel,
which has it's own page.

Since the tank is new, the little Walbro pump is merrily pumping fuel out of the tank, through the Racor, and back into the tank. I'll let it do that non-stop until the engine is in, and by then all the hoses will be very clean, and any manufacturing crud in the tank should be washed away
and filtered out.

Gee, I'm glad this job is done!

Wow, I can't believe it's finally done.

Five years of maintaining little dams of oil absorbent diapers is finally over.

Now I can put in the steering, and start getting the boat back into sailing shape.

Note that the strap on the left is about 1/2" too far to the right.

Too bad.

I still don't really believe it. When I'm sailing again and living a normal life,
I think this effort will finally give me satisfaction.