E34-200 Fuel Tank Tabs

[JSM]

Just hauled our new to us '87 E34-200. Over the course of the season I discovered that the tabs that hold the fuel tank in place have broken off causing the tank to settle. As the amount of fuel in the tank decreased over the summer I noticed that the amount of vibration noise coming from below seemed to increase causing me to believe that the near empty tank is resting on the hull and singing along with the m25xp.
My plan is to remove the tank and have it cleaned and the tabs re welded. I've read elsewhere on the forum that the tank can be removed from the boat in one piece and would like to hear from anyone else who may have done this job.
Is there anything holding the tank in place other than the aluminum tabs at the top ? Also does the tank sit on anything below.
Tanks
JSM

 

[Loren Beach]

Not the same boat and tank, but similar

Different interior and different design... but our particular "34" had tabs welded on the top when built, and their purpose was to keep the tank from resting against the hull surface where moisture could cause corrosion on the outside of the tank. This is "SOP" for proper tank construction in the industry and not all builders follow this standard.

I would opt to remove it and either have new tabs welded on or just have a new tank made in (nowadays) thicker standard wall thickness. When we replaced the factory tank in our boat the new one used a thicker wall.

And, further, I know of several welders that really dislike trying to weld to old aluminum because it's very difficult to get the old surface adequately cleaned of all contaminants and it's vital to weld to clean metal.

Link to thread with some pix of our tank (old and new) with the tabs.
http://www.ericsonyachts.org/infoexchange/showthread.php?6303-Diesel-Tank-replacement&referrerid=28


Regards,
Loren

 

[Christian Williams]

I'm not sure how my 50-gallon tank is secured. All that's visible is fiberglass tabbing. It appears to sit on a bed of expanded foam, possibly added later. Maybe there's a wood platform underneath.

Looks like various solutions, and maybe manufacturers, were involved.

 

[Tom Metzger]

JSM - There is a drawing of the fuel tank on page 33 of the E-34 manual in the down load section of this site.

The tabs are the only support for the tank.

It is 30" wide so it should come out of the boat easily. [Those famous last words.]

 

[JSM]

Thanks All ! Seeing as the tabs are the only support for the tank and they have all failed it looks like I may have to re engineer the support system. We'll see what things look like once the tank is out.

 

[andy beach]

We have a 1990 E-34 and had to replace the tank 2 years ago. It will just fit through the companionway! The tabs are the only support. I am with Loren, if this is your original tank consider having a new one built. The bottom of our tank had that funky corrosion that aluminum gets and had several pin hole leaks. It could have been a real disaster but when checking on the boat one day we could smell the faint odor of diesel. We knew right away the tank was failing when we discovered a couple of gallons of red dye diesel in the bilges. Good luck with your project.

 

[JSM]

Thanks Andy, will definitely take a close look at all aspects of the tank.

 

[JSM]

Pumped out fuel and removed tank yesterday. Job went much smoother than anticipated. The fuel looked nice and clean and the tank seems to be in fine shape. It appears that the tank sort of balances on a "hump" glassed into the hull near the front of the tank leaving the four (weak) tabs to stabilize the tank.
I am going to look into building up the hull under the points where the tabs attach or possible putting some neoprene "feet" on the tank.

 

[Christian Williams]

For what it's worth, it looks like on my boat the factory injected expanding foam into the hollows under the tank to provide a firm bed.

 

[JSM]

Thanks Christian, foam sounds like the way to go. The radiator/tank shop that is doing the welding also recommended the foam option. I will see if I have the room to get in there and inject foam once the tank is back in place.

 

[Guy Stevens]

If you put a plastic bag in there....

If you put a large garbage bag in the area under the tank that you want to foam, and then foam that area inside the garbage bag, it will still form a perfect mount, but will be removable, as will the tank if you or someone else needs to remove either in the future.

Guy

 

[JSM]

Thanks Guy. Great idea, makes clean up easy should things go wrong with the foam . As much as I like the foam approach the problem I see with it is that once the tank is in place I have virtually no access to the area under the tank. The alternative would be to lay the foam in and drop the tank is place before the foam sets up.

 

[Christian Williams]

I used foam on a dinghy--a few paragraphs here gives an idea what to expect:

http://www.ericsonyachts.org/infoexchange/entry.php?206-Flotation-for-the-Dinghy

 

[EGregerson]

tank

Hi; I'd be a little cautious about putting anything under the tank; there's not much hull thickness to support the load. and i think the air from the engine compartment finds it way back that way; it keeps it 'ventilated'. I had 1/4" tabs welded on mine. The welder said they'd never break. I had to cut recesses in the lid to accommodate the thicker tabs.

ps;if u have the original fuel hose (the big one); it might be a good time to replace it while the tank is out; they will leak at the sharp bend where it comes thru from the starboard lazerette.

Fair winds.