I have found this thread very interesting . . . those of you that have had
problems with mild steel diesel tanks, are they rusting from the outside? Is
that the problem? Are they not painted on the outside?
Reason I am asking, many of you know I am in the throes of tearing apart and
rebuilding a 40+ year old steel boat. I am replacing all the underwater
plating, as the boat was neglected for many of its years and suffered from
some severe localized electrolosis, and also corroded from the inside due to
leaking decks, and no bilge pumps after the batteries died. (The owner died,
the heirs did nothing with the boat and she sat unattended in the water at
the dock for 2 years).
Anyway, the point of all of this is that the fuel tanks are integral to the
hull. That is to say, the bottom of the tanks is the hull plating, then they
just boxed in the desired area with more steel, welded in inspection hatches
and fittings, and filled 'em up.
In my inspections of the hull, and cleanout of the tanks, I found no
corrosion at all inside the tanks. Matter of fact, the inside of the diesel
tanks is the only place on the interior below the water line that has no
damage at all. I found white metal (uncorroded, unpainted steel) at the
bottom of the tanks. The hull is full thickness there. There was some mild
surface rust on the underside of the tops of the tanks, but no pitting or
loss of thickness there either.
Forward of the tanks (forward tank bulkhead)I can see there would have been
a problem with the bulkhead corroding on the outside in a few more years
(the forward bilge is against the tanks and was severly damaged by the
neglect), but a bit of epoxy slopped around every 10 years or so probably
would have nipped that in the bud.
These tanks were essentially in excellent condition, after 40+ years,
including two years of complete neglect (water standing in the boat). Mild
steel is so easy to fabricate, horrendously strong, and very inexpensive
that I would have thought it ideal for tanks.
What's happening to the tanks that are failing?
CUAgain,
Daniel Meyer
http://cuagain.manilasites.com
I have found this thread very interesting . . . those of you that have had
problems with mild steel diesel tanks, are they rusting from the outside? Is
that the problem? Are they not painted on the outside?
Reason I am asking, many of you know I am in the throes of tearing apart and
rebuilding a 40+ year old steel boat. I am replacing all the underwater
plating, as the boat was neglected for many of its years and suffered from
some severe localized electrolosis, and also corroded from the inside due to
leaking decks, and no bilge pumps after the batteries died. (The owner died,
the heirs did nothing with the boat and she sat unattended in the water at
the dock for 2 years).
Anyway, the point of all of this is that the fuel tanks are integral to the
hull. That is to say, the bottom of the tanks is the hull plating, then they
just boxed in the desired area with more steel, welded in inspection hatches
and fittings, and filled 'em up.
In my inspections of the hull, and cleanout of the tanks, I found no
corrosion at all inside the tanks. Matter of fact, the inside of the diesel
tanks is the only place on the interior below the water line that has no
damage at all. I found white metal (uncorroded, unpainted steel) at the
bottom of the tanks. The hull is full thickness there. There was some mild
surface rust on the underside of the tops of the tanks, but no pitting or
loss of thickness there either.
Forward of the tanks (forward tank bulkhead)I can see there would have been
a problem with the bulkhead corroding on the outside in a few more years
(the forward bilge is against the tanks and was severly damaged by the
neglect), but a bit of epoxy slopped around every 10 years or so probably
would have nipped that in the bud.
These tanks were essentially in excellent condition, after 40+ years,
including two years of complete neglect (water standing in the boat). Mild
steel is so easy to fabricate, horrendously strong, and very inexpensive
that I would have thought it ideal for tanks.
What's happening to the tanks that are failing?
CUAgain,
Daniel Meyer
http://cuagain.manilasites.com
