Built-in Diesel fuel tank trouble

[Disielcustoms]

I have 2 builtin diesel fuel tanks on my boat and the paint or coating inside is bubbling/wrinkling up. I really don't want to rip up my floor and saloon to have new hard tanks made and install in the space of the built-in ones. So what are my option? Has anybody had this problem and used custom-made fuel bladders and placed them in the exiting prefab tanks?

[coopec43]

I would never consider a "builtin" water tank because you don't have control over temperatures and the curing process. The Gougeon Bros (West System) advise against constructing water tanks that way because of the danger of uncured epoxy to your health

Diesel is far more penetrating than water and will find pinholes and "wick" where water won't. If there is any uncured resin diesel will find it. (Of course diesel weeping out of pinholes is not confined to fiberglass but aluminum, steel and SS as well). Of course fiberglass tanks built in controlled conditions in a factory are fine.

[GRIT]

We have built-in tanks too, but in our case, I'd resurface the tanks, rather than install a bladder.

You should be fine with bladders. Just check that there aren't any sharp edges of "stray" glass, from the original build. If there are baffles in the tanks, they'll have to be removed, to make room for the bladder.

My first choice would be rehab the existing tanks, if that's possible. I don't know how the access is for those tanks, but removing the baffles might be nearly as much work as resurfacing the tanks.

Perhaps you should get a fibreglassing guy to look, and give you a quote, before making any decisions.

Good luck.
Paul.

[tkeithlu]

Are the tanks weeping or leaving a diesel smell on the outside? If they are weeping, then refinishing the inside or bladders come to mind - the tank is not doing its job. On the other hand, if the peeling is superficial, and the tank is sound, the first try might be cleaning the inside, getting rid of the peel, before it comes down your fuel line and clogs the filter. Then decide if it needs refinishing. The advice of the fiberglas person is germane.

Looking at my own problem solving, I find that little steps toward the solution rather than drastic action up front usually serves me well. Try the little steps first.

[coopec43]

Disielcustoms

I don't know what size your yacht Luna is but there is no chance of the hull is flexing slightly where the tank is is there?

[Tayana42]

Dieselcustoms, I did this after one of my black iron diesel tanks developed a pin hole leak. Same problem of inaccessibility for removal of the tank without demolishing the interior of the cabin. I had a flexible tank made and inserted it inside of the existing tank.

In addition to opening up the top of the tank you have to remove any baffles in the tank and grind them down smooth so as not to have any chafe on the bladder. I also padded the inside of the iron tank with rubber decking tiles before inserting the bladder. You want a high quality bladder tank builder to manufacture one to the exact dimensions of the inside of your existing tank so you need to measure the rhomboid shaped tank very carefully.

I used Aero Tec Laboratories, Inc.
Spear Road
Ramsey, New Jersey 07440

201-825-1400
ATL@ATLINC.COM

Cost was $1296 in 2004. That was in addition to the cost of grinding out the baffles in the iron tank and installing the bladder.

It has been 15 years now and I have had no problems with my bladder tank inside the old tank. Best of luck in your project.

[Cheechako]

Would it be possible to cut out the top and put plastic new tanks in the old metal ones? maybe 2 plastic in one large old metal tank? I considered that at one time. Most my boats had far more tankage than I really needed anyway and that just resulted in the fuel getting old.

[coopec43]

Originally Posted by Cheechako

Would it be possible to cut out the top and put plastic new tanks in the old metal ones? maybe 2 plastic in one large old metal tank? I considered that at one time. Most my boats had far more tankage than I really needed anyway and that just resulted in the fuel getting old.

I don't know what the cost of having custom-made plastic tanks to fit in the old tanks would be but I imagine they would not be cheap (Hatteras and Bertram have switched from fiberglass to plastic)

But if you are proficient with fiberglass you should be able to make up good fiberglass tanks to fit into your old tanks. (Don't try it as a first off fiberglass project!)

[RaymondR]

Originally Posted by Tayana42

Dieselcustoms, I did this after one of my black iron diesel tanks developed a pin hole leak. Same problem of inaccessibility for removal of the tank without demolishing the interior of the cabin. I had a flexible tank made and inserted it inside of the existing tank.

In addition to opening up the top of the tank you have to remove any baffles in the tank and grind them down smooth so as not to have any chafe on the bladder. I also padded the inside of the iron tank with rubber decking tiles before inserting the bladder. You want a high quality bladder tank builder to manufacture one to the exact dimensions of the inside of your existing tank so you need to measure the rhomboid shaped tank very carefully.

I used Aero Tec Laboratories, Inc.
Spear Road
Ramsey, New Jersey 07440

201-825-1400

ATL@ATLINC.COM

Cost was $1296 in 2004. That was in addition to the cost of grinding out the baffles in the iron tank and installing the bladder.

It has been 15 years now and I have had no problems with my bladder tank inside the old tank. Best of luck in your project.

That was a smart move with the rubber decking tiles mate. I must remember it if I have to do the same thing myself.

[Tayana42]

Thanks RaymondR. I was very careful to avoid any potential chafing and it seems to have paid off.