Black Iron Fuel Tanks

[clarity36]

Crew
Considering a recently launched (2004) cruising centre cockpit that has had black iron fuel tanks fitted. The boat is professionally fitted out in all respects, but an iron fuel tank? Have any members experience with this type of fuel storage? Cheers. Bill

[CaptHead]

I have black iron fuel tanks on my 1966 GB trawler which are original. Keep them painted and they will last a long time. Most iron tanks rust from the outside in so keeping the outside coated and rust free is your best insurance.

Most boat builders used Iron tanks and still do.

[Vasco]

Common on a lot of older Taiwan built boats. Lots of problems. Don't know any 2004 boats that have them.

[SabreKai]

I take it that welded sheet steel tanks are not the same thing? I have one tank made from 1/8 plate. Its welded in place, has no guage or sightglass. Its been there for 30 years and appears to be sound. If I can figure out a way to access the area, I'll have a closer look but for now it's visible but unreachable.

Just another thing to be set right.

Sabre

[speedoo]

Originally Posted by SabreKai

I take it that welded sheet steel tanks are not the same thing? I have one tank made from 1/8 plate. Its welded in place, has no guage or sightglass. Its been there for 30 years and appears to be sound. If I can figure out a way to access the area, I'll have a closer look but for now it's visible but unreachable.

Just another thing to be set right.

Sabre

I assume your boat is steel. And it occurs to me that this is another advantage for steel boats. You probably have better access to that tank from outside the hull, so when it fails, just cut through the hull, replace the tank, and re-weld the hull.

Much, much easier than taking apart the interior of the boat to get at that tank. (trust me, I know from experience!)

And I do think welded steel tanks are the same thing as black iron, as long as you are not talking about stainless.

[Mike156]

In the vast majority of cases where boat owners, surveyors, and brokers describe a tank as “black iron” they are really describing a tank made of mild steel.

I’d like to meet the person who first started calling Taiwanese steel tanks “black iron” and ask him why he did that.

Steel tanks can rust. All steel rusts if not protected.

Steel tanks can last a long time if protected from water.

Check the coating on the tank.

Mike

[Roy M]

Screw metal tanks, period. Build your diesel fuel tanks out of plywood, sealed with WEST System (or other) epoxy resin. Add the inspection plates of your dreams, add baffles wher you want them. Do it for half the weight and a quarter the price. I have been building these tanks for customers for over thirty years. For insurance purposes, they are classed as cellulose core composite structures. Two years ago I cut out a piece to install a fuel gauge sender in my own tank. The odor of fresh plywood was pervasive. No diesel incursion, whatsoever. Don't be hornswoggled. The Gougeon Brothers developed this technique many years ago, but folks are often slow to accept new (thirty-something year-old) technology. Geez! No electrolysis, ease of cleaning, and several lifetimes, at a minimum, of longevity. Now I'll stand back and watch the fireworks as "experts" with vested interests in the status quo display their brilliance. Please forgive my volubility, we just had a fabulous storm in San Diego and I've had several hot buttered rums to celebrate.

[SabreKai]

Actually you won't get an argument out of me on plywood/epoxy tanks. I've seen a few of them and have spent enough time working with the West System to know what its capable of.

I have that abortion of a tank sitting there and I may yet remove it and remake it out of plywood.

Sabre

[speedoo]

OK, I was getting ready to replace a 60 gal. diesel tank with a new aluminum tank, but I am certainly willing to go the plywood/West route if someone could tell me where to read up on it.

How about a quick overview.... what kind of plywood? What thickness? Epoxy both outside and inside? What do you use to put it together... screws and epoxy?

And what about the same system for a water tank? Just have to use an epoxy that is safe for potable water, right?

[bobfnbw]

http://www.boatdesign.net/forums/boa...tanks-278.html

that is a good place for you to start.

Make sure your insurance company is ok with it.... or take a chance...
I ordered a new aluminum tank, but considered building my own. Seemed easier to order the new one.
Fuel can be a dangerous thing.

[Roy M]

Geez. Read the #%&!** Gougeon book. Fuel CAN be dangerous. That's why you don't want to contain it in a material that disintegrates with stray electrons, water in the fuel, and the galvanic table. Your insurance company hasn't a clue in the first place. They don't even understand the concept of composite structures. Fortunately, the aviation industry, the military, and boatbuilders who got beyond tarred marline and treenails discovered this stuff decades ago. If you don't have any experience with this stuff, why waste the time of folks who have been using it for several dog's ages? Sorry, I'm just responding to folks who don't get out much, yet need to inject their two cents worth. People who don't get it should either learn something new or get out of the way of change. This is old technology, not psuedotech. It works, it has worked for decades. It's relatively cheap. It's versatile and user friendly. And, it's safer than metal tanks, in every respect.

Editor's note: Roy M has found the bottle of Prozac and is now comfortably tucked away in his berth. Please disregard his prolific use of upper case symbols, it was the acetone fumes that were talking.

[Chief Engineer]

AT LEAST HE DIDN'T TTYPE IN ALL CAPS

or

used a big font!!!!!!!!

[bobfnbw]

Fuel Tank Considerations
Fuel tank building is a controversial area. There are several USCG regulations and ABYC standards governing fuel systems. Actually, the USCG regulations are only applicable for gasoline fuel systems, not diesel fuel. Because of gasoline's lower flash point, higher volatility and combustibility, gasoline systems are more regulated than diesel fuel systems. These regulations are very specific and contain stringent requirements for the fill systems, vents, installation, testing and labeling.

Although the USCG doesn't publish any regulations for recreational boat diesel fuel systems, ABYC publishes a written a standard, Standard H-33-Diesel Fuel Systems. It would behoove customers to obtain a copy to ensure all safety precautions and recommended practices are followed.

Conclusion
All types and variations of tanks have been successfully constructed with WEST SYSTEM Brand epoxy and used in the field with great results. However, Gougeon Brothers does not condone or recommend that certain tanks be built because of various issues noted above. In our testing, various epoxy combinations have proven to be resistant to various liquids, including gasoline, diesel fuel, motor oil, potable water, sea water, sewage, gray water, etc. Regarding gasoline specifically, some epoxy combinations are more resistant than others are. With the increasing use of alcohol and other high-tech additives, we are unsure how the epoxy will resist them in the future. We do know that many types of alcohol vigorously attack epoxy, we can only conclude that gasoline with a higher percentage of alcohol may not have favorable results in long-term use.

Before building gasoline tanks and potable water tanks, do your homework and take into consideration the information above. The resources and various agencies noted below should help you make informed decisions regarding tanks and whether or not you should build your own. The final decision to build or not to build rests on the builder, we hope this document helps the builder make sound, educated decisions. As always, please contact the Technical Staff if specific questions arise.

Taken directly form the site I linked in the above post. I didn't say don't do it, just that I didn't do it. I chose to go with what others think is the best comprimise for diesel fuel tanks and that is aluminum. My aluminum tank lasted 25 years or so, and hopefully the next one longer due to keeping the bottom out of bilge water.
If you want to build with epoxy, go ahead. Let us know how it went, post pictures of the building process please. We are all interested.

But keep your rants to your self. Please.

[Roy M]

Speedo, the key guideline for designing your fuel tank is to prevent "oilcanning" of the sides. If 1/4" ply with internal baffles gives you the necessary rigidity, go for it. I built my first tank of 3/8" A-C exterior Douglas fir ply. In retrospect, I could have used 1/4" since the 55 gallon tank is only 40" long, by about 18" high, and fits the hull cavity it occupies so that the tank can be removed completely to make hull repairs, if necessary. I used graphite powder to make the surfaces opaque black and give it an air of mystery. No glass was used, but I did give all interior intersections generous "beercan fillets" for strength and to make cleaning as simple as wiping with a towel. Before installing the top of the tank, build your baffle(s) where you want them to keep the fuel sloshing fore and aft. I drilled big holes in mine to reduce weight. The tank itself weighs under thirty pounds. Make all penetrations from the top, including fill tube, vent and fuel pickup. I also installed a fuel gauge sender and fuel level dipstick (brass rod with tee handle, inserted in a pipe cap and brazed, then the whole thing inserted in a 1/4" threaded nipple. The dipstick was then calibrated by adding five gallon increments of fuel and notching the dip stick). With epoxy, you can use your plumbing fittings to create the threaded base. Simply use wax to act as the release compound on the male thread of the fitting, paint it with thickened epoxy, and screw it into an epoxied hole in the top. When it cures, unscrew the fitting, use an appropriate sealant, and screw it back it. As for cleanout/inspection ports, make them BIG (Sorry Chief, I got carried away with the caps) by using a large hole saw for the corners, connect the tangents and cut the wood out with a sabresaw. Ease the edges and epoxy. Make covers that overlap the openings by at least an inch. Drill through the cover and the tank top to establish the holes for fasteners. Make the holes larger than the machine screws (I use 1/4" stainless hex heads. Seal all the edges and use the machine screws, waxed as before, to make the internal threads. You can then use a conventional fuel-proof flexible sealant to seal the perimeter of the lid when you are done. In the future, to pop the cover off, I simply remove the fasteners, tap the edge of the lid with a putty knife, and pop! Off it comes. It is so easy to clean the interior of the fuel tank that you don't need to stress out with fuel polishing. Just pump the fuel out, wipe the interior of the tank with a paper towel, the run the fuel through a Baja fuel filter to clean it up.

Water tanks aren't a good idea for epoxy. There will always be the slight danger of contamination of the drinking supply by leaching of some epoxy components (ketones and other nasty stuff that we should avoid ingesting). I prefer polyethylene tanks to reduce any potential health hazard. When I replace my water system, I will also be using the new (relatively) polyethylene tubing systems, as well.

And my apologies to anyone offended by my antics and enthusiasm.

[DeepFrz]

Please note the warnings on the West System web site. Please read all you can about what is necessary in building a fuel tank.

It is probably better to purchase fuel tanks made by a company that specializes in the construction of fuel tanks than to try and build your own.

Actually experts in the field are recommending fuel grade vinylester/glass rather than epoxy. If you must use plywood, please do use glass to reinforce the tank. This is especially important at the corners, fillets on their own are not likely to hold. Plywood is (IMHO) not a good material for a fuel tank.