Fuel Tank installation advice sought

[Paul Bell]

I removed the 60 gal aluminum tank to repair some wood damage on my 89 Celebrity.
The tank rested directly on the hull with only a very thin and worn rubberized strip of tape between the tank and hull.
There was next to no protection for the tank to move around since also the eight screws had come out.
A few of the screws ended up beneath the tank and could have worn through but had not.
Should there be something the tank rests on or protected with as oppossed to direct hull contact?
I would like to reset the tank and provide a means to protect from wear or abrasion and would appreciate any advice.

 

[tashasdaddy]

Re: Fuel Tank installation advice sought

here's some info.
http://www.moellermarine.com/amdownloads/fuel_tank_install/

 

[jonesg]

Re: Fuel Tank installation advice sought

I removed the 60 gal aluminum tank to repair some wood damage on my 89 Celebrity.
The tank rested directly on the hull with only a very thin and worn rubberized strip of tape between the tank and hull.
There was next to no protection for the tank to move around since also the eight screws had come out.
A few of the screws ended up beneath the tank and could have worn through but had not.
Should there be something the tank rests on or protected with as oppossed to direct hull contact?
I would like to reset the tank and provide a means to protect from wear or abrasion and would appreciate any advice.

Rubber shouldn't be used, sounds like it was installed wrong, it shouldn't be resting on the hull at all ...either with pads or without, anyway read this.

http://www.yachtsurvey.com/fueltank.htm

 

[Paul Bell]

Re: Fuel Tank installation advice sought

Something did not seem right as it not only sat right on the hull but any bilge water would flow right underneath and keep the tank wet.
A few stainless steel screws got underneath and left some good scratchs in the tank.
Thanks for the great advice.

 

[JorgeE]

Re: Fuel Tank installation advice sought

Ok guys... just curious...
Many boats have belly tanks just like Paul's (and mine). Most are longer and narrower, but essentially the same design. The photo from Lou C on Paul's "Deck Soft Spot Adventure..." thread shows support brackets just like our tanks have... way too small to hold up the tank, there (I think) just to keep the tank form shifting fore/aft...
How are these belly tanks supported on other boats out there? surely there are some that have had the tanks out and saw how they were supported. Any comments on evidence of damage or impending doom from bad OE installation would also be great.
I'll also be glancing around on projects...

Thanks to all. Advice is great. I have read much more than posted, and (I hope) have learned much from all you.

Jorge

PS: Just ran across this info, please comments:
http://www.bertram31.com/proj/tips/fuel_tank.htm

 

[83ProLine]

Re: Fuel Tank installation advice sought

This is very interesting thread. . .

I have a 69gallon tank (aluminum alloy) that lays in the belly of the hull between my two inside stringers. When I gutted the boat, the tank was resting on mounts to keep the tank off the hull, and foam had been poured in between the stringers and the tank to keep it from shifting around. There were no brackets to remove.

I cut the foam out and thought the tank would lift right up, only to discover that the tank was pretty-darn stuck to the mounts. I had to use a crow bar to pry it up.

I assume they layed the tank down onto resin and glassed it to the mount? What are the disadvantages of replicating this process when I reinstall the tank?

Regards,

James

 

[a70eliminator]

Re: Fuel Tank installation advice sought

My 1990 Chaparral's tank was below the deck between the stringers sitting on rubber pads directly onto the hull, it was anchored in place with two wooden crossmembers over the top of tank toenailed into the stringers wedging the tank down in.

 

[Mark42]

Re: Fuel Tank installation advice sought

Some Fuel Tank Install basics from the USCG:

- The tank cannot move more than one-fourth inch in any direction, measured at its mounting surface when force is applied in the forward, aft, port, starboard, and vertical directions.

- The fuel tank does not support a deck, bulkhead, or other structural component

- Water will drain from the metallic fuel tank surface when the boat is in Its static floating position, or
The tank is effectively coated to prevent water from contacting the metal surface.

- The fuel tank supports, chocks or straps are integral with the fuel tank or
The fuel tank supports, chocks or straps are insulated from the fuel tank by non-moisture absorbing material

Basically, this requirement provides for the isolation of the metallic fuel tank from a potentially moisture laden support system and also from abrasion by the supports, chocks and straps.
The following table lists some materials that appear to be suitable and some that should
be avoided.

Fuel Tank Isolation Materials
Suitable
Neoprene
Teflon
High Density Plastics

Unsuitable
Cardboard
Carpeting
Unpainted Wood
Felt
Canvas
Foams

NOTE:
These lists are not limiting in the materials to be included. They are to establish the intent of the regulatory requirement prohibiting moisture absorbent materials. If possible, the isolation materials should be bonded (glued) to the tank so that moisture (from condensation) cannot be trapped next to the tank.

Read the whole section on fuel tank installation here: http://www.uscgboating.org/safety/boatbuilder/fuel/183-550-a.htm

These regs are really intended for boat manufacturers, but you know you will be doing it right if you follow the regs. And if there is ever any problem, there will be no issues with insurance claims or liability because of an inproperly installed tank.

I am currently installing a permanent tank in my boat. Because it will be above the deck (under the splashwell) it is visable, so I am making sure that the tank and the install and all hoses meet CG regs. I dont want any problems from CG inspection or any other source. Yes, it costs a little more to meet these regs, but its well worth it.

If you want to use neoprene to rest the tank on, I found some at mcmaster.com

 

[jonesg]

Re: Fuel Tank installation advice sought

Aluminum tanks shouldn't be foamed in place in a manner such as will allow water to become trapped against the tank, crevice corrosion occurs like that.
Its fine to set it on glassed support planks with 5200 and a couple of braces across the top with 5200 again. Thats what I've read anyway.

I had a 55 gal galvi that corroded because it sat in water at the aft end.
Support , ventilation and drainage are the keys.

Read the link I posted already.

 

[83ProLine]

Re: Fuel Tank installation advice sought

Read the link I posted already.

http://www.yachtsurvey.com/fueltank.htm

That is a great link for how to install an aluminum tank!

I dont know that I necessarily understand his comment at the end:
"Aluminum tanks are not expensive, so if you need to make modifications to the original shape, be prepared to do so"

None-the-less, great stuff!

Regards,

James

 

[Lou C]

Re: Fuel Tank installation advice sought

The way the tank compartment was made in my boat was that the tank is not resting on the bottom of the hull per se, but FW built in a floor so to speak in the bottom of the hull, that is straight across so that a rectangular tank will sit level on it. The tank was secured from moving with 4 tabs welded to the tank. I built a stronger frame than was there, with lengths of mahogony attached to the main center stringers of the boat, the tabs on the tank are attached to them. Believe it or not the original installation had firring strips screwed into the stringers and the tank tabs were screwed into these flimsy firring strips. What I put in is a lot stronger and more secure. BTW, when I took it all apart in 2005/6 for the rebuild, two of the mounts had rotted off! In my pics you can see the darker colored wood is the framing for the tank.

 

[83ProLine]

Re: Fuel Tank installation advice sought

I have nearly the same tank pictured above - except my tank doesnt have the tabs.

Strange that your fill valve is at the lower end of the tank? I fill from the side of my boat, up towards the front - so mine is on the other end.

Regards,

James

 

[LX Kid]

Re: Fuel Tank installation advice sought

I've still got both of my repaired tanks out and really found this posting a "big" help for me. The links posted here are great informational sites on the proper installation of tanks. Mine happens to be aluminum. Thanks fellow board members. I almost was ready to make a big mistake in their installation! Ron

 

[jonesg]

Re: Fuel Tank installation advice sought

That is a great link for how to install an aluminum tank!

I dont know that I necessarily understand his comment at the end:
"Aluminum tanks are not expensive, so if you need to make modifications to the original shape, be prepared to do so"

None-the-less, great stuff!

Regards,

James

Relative to stainless steel ?

 

[jonesg]

Re: Fuel Tank installation advice sought

I have nearly the same tank pictured above - except my tank doesnt have the tabs.

Strange that your fill valve is at the lower end of the tank? I fill from the side of my boat, up towards the front - so mine is on the other end.

Regards,

James

Yeh but his overflow is at the high end (fwd), when its full its full.

 

[JorgeE]

Re: Fuel Tank installation advice sought

Mark,
The info was great! thanks.
To reinforce the fact that one should NOT believe all we read on the internet, I ran across a website (http://www.bertram31.com/proj/tips/fuel_tank.htm)
that recommended that sheets of poly be used to allow using the tank as a sort of mold, and to keep the tank from bonding to poured-in foam. This is in direct contradiction to the USCG link provided by Mark - I think I'll follow the ISCG info. The bertram website does take steps to protect the tank from corrosion, but still against ISCG guidelines.
Thanks for the great info.
Jorge

 

[projecthog]

Re: Fuel Tank installation advice sought

The article is compliant....., it says to lift the tank out and remove the wrap after the foam has set, I believe that will give you the (+/_) 1/4 inch play the CG requires.
PH.

 

[jonesg]

Re: Fuel Tank installation advice sought

The article is compliant....., it says to lift the tank out and remove the wrap after the foam has set, I believe that will give you the (+/_) 1/4 inch play the CG requires.
PH.

The downside is the expense of coal tar epoxy and foam.
And the loss of air circulation.

The plus side is you get more floatation.

 

[Mark42]

Re: Fuel Tank installation advice sought

The article is compliant....., it says to lift the tank out and remove the wrap after the foam has set, I believe that will give you the (+/_) 1/4 inch play the CG requires.
PH.

The CG does not require a 1/4" play, it ALLOWS a 1/4" play. The foam job as described in that link leaves a zero clearance, and the real problem with that is water will tend to stay between the tank and the foam. Even barrier paints will fail eventually.

I think plastic tanks are the way to go when replacing one.