Fiberglass DIESEL fuel tanks

Diesel tankage is on a 10 knot vessel, not affected by USCG, ABYC, FDA etc and not in survey

Before making the decision to do what I did I read all the info such as this
http://www.boatdesign.net/forums/boat-building/epoxy-fuel-tanks-278.html

The current situation is I have 6 separate underfloor tanks as part of the structure of my vessel with timber core and epoxy as the material used.
Once cured, all surfaces have had additional layers of glass and then an additional resin coat, so they are sealed well and truly.
Fuel from these will be pumped and scrubbed daily up to alloy day tanks before gravity feeding back to engines.
Full fuel load inc. day tanks was to be approx 2400litres +- for a 2400nm +- range

Now, I have started having doubts as to whether or not I went the right way here.

If not using these my only other alternative is to add 2 alloy tanks
These will take 1/2 the bench space on one side of each hull
They will reduce my total tankage by approx 1400 litres +- and 1400nm +-.

Obviously, this is not something I really want to happen

Has anyone got any CURRENT information regarding Epoxy Diesel Tanks that may put my doubts at rest.

Thanks in advance

 

From what does your doubt arise ? Are you concerned there is some slow internal disintegration going on in the tanks ? Best advice I could give would be drain them and inspect using one of those scopes ( not sure what they call them ) which is like a camera on the end of a flexible cable. Like a colonoscopy gizmo. Mechanics use this type of thing to inspect engine internals without dis-assembly.

 

mate youll be fine... nothing wrong with fiberglass tanks... your only consideration might be, How do i get inside to clean them if i need to? For me, this would involve cutting a hole in the top and then repairing it once finished... no big deal considering you built the thing in the first place...

 

Polyester tanks work fine, so epoxy will have no problem.

 

When I made tanks (petrol) from polyester/glass I was advised to use Isothalic resin only.

 

Petrol (gasoline), especially with ethanol added, has very adverse affects on FRP. But diesel does not. Many companies build fiberglass tanks in their diesel power boats with great success. For instance Hatteras Yachts build FRP tanks in their yachts. So as has been said, they should be fine.

 

I never had any problems, but no ethanol used.

 

You're one of the luck y ones. There have been many well documented problems with fiberglass gas tanks. http://www.boatus.com/seaworthy/fueltest.asp

 

Nothing to do with luck.. just ethanol.

 

OK, so It would seem I am still looking ok with epoxy/diesel, that's good.
Panic averted

I really didnt want to have to reduce tankage and range plus lose bench space going the smaller ally tank route.

 

I am hoping that an hour or so a day of pumping and recirculating through my bank of "Fg500's" before topping up the day tanks will take care of that.

Of course once the passage is done I will only keep 2 of the six storage tanks filled so I may well have issues there with the 4 empties.
Suggestions?

 

Circulating from tank to tank is more efficient (for fuel polishing) so you can use all of them and have all tanks clean all the time.

 

Perhaps you can make integral fiberglass tanks. I wouldn't. Ive seen so many problems over the years that I would go plastic.
Ive never seen a problem with correctly installed plastic tanks.

 

Nothing done correctly is a problem.. not integral gf, metal nor plastic
Do it wrong and material choices won't help..

 

So long as Diesel stays Diesel. Builders who did early built in fuel takes for gasoline did them correctly. They didn't know ethanol was coming.