If everything goes according to plan, I'm about to buy a Grand Banks
49 trawler that needs new fuel tanks (500 gallons each).

Any thoughts from this group on the best material for new tanks,
fabrication hints, and/or removal/installation suggestions?

This can be the single biggest problem to fix - depending on the
location, access, etc. New tanks are expensive and R&R is expensive.

Proper new diesel tanks that size should be made out of 1/4 - 5/16
alum - depending on the dimensions.

What's the matter with the original tanks?

Have you really thought this through. You need several hard estimates
before you close the deal.



On Thu, 03 Jun 2004 00:03:35 -0400, Wayne.B
wrote:

If everything goes according to plan, I'm about to buy a Grand Banks
49 trawler that needs new fuel tanks (500 gallons each).

Any thoughts from this group on the best material for new tanks,
fabrication hints, and/or removal/installation suggestions?

On Thu, 03 Jun 2004 15:15:54 -0700, Mark wrote:

Have you really thought this through. You need several hard estimates
before you close the deal.

========================================

I've gotten several estimates (all over $30K), and a large enough
survey adjustment to make for a satisfactory deal.

Have you had any tanks made from 1/4 or 5/16 aluminum? I'm
particularly looking for fabrication advice regarding coatings,
geometry, baffles, fill/vent/drain fittings, etc.

The tanks will be made by a contractor but I want to be sure they are
spec'd properly.

"Wayne.B" wrote in message
...
On Thu, 03 Jun 2004 15:15:54 -0700, Mark wrote:

Have you really thought this through. You need several hard estimates
before you close the deal.

========================================

I've gotten several estimates (all over $30K), and a large enough
survey adjustment to make for a satisfactory deal.

Have you had any tanks made from 1/4 or 5/16 aluminum? I'm
particularly looking for fabrication advice regarding coatings,
geometry, baffles, fill/vent/drain fittings, etc.

The tanks will be made by a contractor but I want to be sure they are
spec'd properly.

I'd hire a naval architect for a day. Stuff like designing a 500 gallon
tank probably should not be left to a contractor.

Baffles will be absolutely required, about every 24-30", External
stiffeners will probably be required, depending on the head on the tank
(height from bottom of tank to top of the vent). Geometry - will you
duplicate the existing tanks?


--
Evan Gatehouse

you'll have to rewrite my email address to get to me
ceilydh AT 3web dot net
(fools the spammers)

On Thu, 3 Jun 2004 23:15:17 -0700, "Evan Gatehouse"
wrote:

Geometry - will you
duplicate the existing tanks?

===========================

The existing tanks are hard to see until taken out.

Wayne, you are talking about a reasonable effort and significant cost
regardless of the material chosen, Do not use aluminum, it is far too
reactive. Do not use gavanized steel. The diesel will disolve the zinc. The
ultimate material should be 316TI SS and next best would be mild steel
blasted and painted with the special Permatex tank paint. This paint is
designed for large storage tanks and must be ordered specially. I just
finished 2 water tanks slightly smaller than yours in stainless and the
material cost was $3200 and that included access hatches.
Steve

"Wayne.B" wrote in message
...
If everything goes according to plan, I'm about to buy a Grand Banks
49 trawler that needs new fuel tanks (500 gallons each).

Any thoughts from this group on the best material for new tanks,
fabrication hints, and/or removal/installation suggestions?

On Sat, 5 Jun 2004 07:08:12 +0200, "Steve Lusardi"
wrote:
Wayne, you are talking about a reasonable effort and significant cost
regardless of the material chosen, Do not use aluminum, it is far too
reactive. Do not use gavanized steel. The diesel will disolve the zinc. The
ultimate material should be 316TI SS and next best would be mild steel
blasted and painted with the special Permatex tank paint. This paint is
designed for large storage tanks and must be ordered specially. I just
finished 2 water tanks slightly smaller than yours in stainless and the
material cost was $3200 and that included access hatches.
=============================

Steve, a couple of questions:

1. Dou you use the Permatex both inside and out? Manufacturer?

2. I've always heard that SS tanks for diesel were a problem because
of weld corrosion. Is that not a problem with 316TI?

I was told 5052 aluminum is better than any stainless, and that stainless
tends to stress crack. I am sure there are many perfectly good stainless and
aluminum tanks out there. I would not even think about mild steel, it will
eventually start to rust.

"Wayne.B" wrote in message
...
On Sat, 5 Jun 2004 07:08:12 +0200, "Steve Lusardi"
wrote:
Wayne, you are talking about a reasonable effort and significant cost
regardless of the material chosen, Do not use aluminum, it is far too
reactive. Do not use gavanized steel. The diesel will disolve the zinc.
The
ultimate material should be 316TI SS and next best would be mild steel
blasted and painted with the special Permatex tank paint. This paint is
designed for large storage tanks and must be ordered specially. I just
finished 2 water tanks slightly smaller than yours in stainless and the
material cost was $3200 and that included access hatches.
=============================

Steve, a couple of questions:

1. Dou you use the Permatex both inside and out? Manufacturer?

2. I've always heard that SS tanks for diesel were a problem because
of weld corrosion. Is that not a problem with 316TI?

5052 is a marine grade aluminum, but aluminum of any type is very reactive
when exposed and unprotected. I suggest that these tanks, once installed
will not offer access to all surfaces impeding inspection and maintenance.
In that light, I would not use it. 316TI is the chemical industry's material
of choice for corrosive environments. It is correct that SS will corrode
(crevise corrosion), but that takes stagnant water without oxygen and that
case will not exist is this application. If all welds are properly
passivated, inside and out, then there should be no corrosion. However by
far, the majority of diesel tanks are made very successfully of mild steel.
The success of mild steel is significantly enhanced when the INSIDE of the
tank is coated with this permatex product. This paint was developed for the
USAF for their underground jet fuel storage tanks. It is sold by the kilo
and has a 30 day shelf life. This has a very high lead content and is
hazardous to apply. Proper breathing gear is a must. It is sold to
professionals only. Another solution for these tanks would be polypropylene.
It can be welded, so custom fabrications are very possible and static
electricity and corrosion are not a problem. I believe all Chrysler vehicles
now use this. As a cost, I would estimate $3000 to $4000 per tank would be
close. Just as a side item, I use mild steel for diesel and 316TI for
drinking water.
Steve

"habbi" wrote in message
...
I was told 5052 aluminum is better than any stainless, and that stainless
tends to stress crack. I am sure there are many perfectly good stainless
and
aluminum tanks out there. I would not even think about mild steel, it will
eventually start to rust.

"Wayne.B" wrote in message
...
On Sat, 5 Jun 2004 07:08:12 +0200, "Steve Lusardi"
wrote:
Wayne, you are talking about a reasonable effort and significant cost
regardless of the material chosen, Do not use aluminum, it is far too
reactive. Do not use gavanized steel. The diesel will disolve the zinc.
The
ultimate material should be 316TI SS and next best would be mild steel
blasted and painted with the special Permatex tank paint. This paint is
designed for large storage tanks and must be ordered specially. I just
finished 2 water tanks slightly smaller than yours in stainless and the
material cost was $3200 and that included access hatches.
=============================

Steve, a couple of questions:

1. Dou you use the Permatex both inside and out? Manufacturer?

2. I've always heard that SS tanks for diesel were a problem because
of weld corrosion. Is that not a problem with 316TI?

On Sat, 5 Jun 2004 19:47:57 +0200, "Steve Lusardi"
wrote:
As a cost, I would estimate $3000 to $4000 per tank would be
close.

Thanks for the information, estimates are close to what I've received.

The realy BIG costs are removal and re-installation - holes to be cut,
reglassed, painted, etc.

What do you use for fittings, and do you take special precautions to
isolate dis-similar metals?