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Black Iron Fuel Tanks

PostPosted: Sun Nov 04, 2007 5:58 pm
by harlenw
I am hoping that you all will let a power boater into your group as I have a question about black iron fuel tanks that are on a 1988 Hans Christian 45’ Trawler that I am looking at.

I read your archives about black iron tanks and have thoroughly Googled the Web about them. I have found that there is no clear modern definition as to what “black Iron” actually means. Most sources state that it is a misnomer for mild steel. A metallurgy text I found from the early 1900s defined it as low carbon steel. I have also found several citations stating that the tanks could not be true black iron because it is too hard to weld into a tank as large as we see in our boats.

The key issue is, of course, corrosion resistance. The HC 45’ independence Trawler I am looking at is 19 years old and has four of these tanks. A leaking fuel tank is a serious and costly issue to deal with.

I would appreciate hearing from HC 45’ Trawler owners out there regarding their experience with the tanks as well as from any other HC owners who have them.

Thanks very much.


PostPosted: Tue Nov 06, 2007 5:45 pm
by mike
From my own experience with the 43t yacht, our tanks are mild steel which are still bright & clean inside. They were epoxied on the outside & the tops which are the only part visible are rust free & clean, hopefully the rest of the tanks are the same.


Black Iron fuel tanks

PostPosted: Sat Dec 15, 2007 9:45 pm
by captnbob
I own an Independence 45 and prior to my purchase, I researched the same subject.

Typical black iron tanks will be damaged by continuous contact with water, that is why these tanks are encased in fiberglass. By eliminating the chance of contentious contact with a wet surface, these tanks should last for the life of the boat.

PostPosted: Mon Mar 03, 2008 3:41 am
by harlenw
CaptnBob, I can’t remember if I responded to your post previously. I am close to purchasing a 1988 45’ Independence Trawler. As you say, the outside of the tanks are fiberglass encased but have you examined the interior of your tanks for corrosion? Some people commenting on my posts about this boat suggest that condensation can occur in 20 year old tanks that could cause corrosion internally. What year is your boat and have you ever examined the inside of the tanks?



PostPosted: Mon Mar 03, 2008 4:37 am
by captnbob

After purchasing the boat, I had a professional open all four tanks and polish the fuel while transferring the fuel between tanks. I didn't see them myself, but the polisher didn't see anything to be concerned about. He recommended regular use of a fuel additive that disperses water from condensation. Each tank has a port about 8" in diameter if you are concerned.

Can you tell me which Independence 45 you are buying (current name or hull #)? Mine is #3. Would like to hear more about you boat.


PostPosted: Sat Aug 09, 2008 5:40 pm
by warmrain
At least as far as the HC33T is conserned, black iron fuel tanks are a myth... the specifications list them... but they are stainless capped fiberglass.

PostPosted: Sat Mar 16, 2013 11:08 am
by turbin
We have clean out our two fueltanks. In the lowest corner it was some pittings, rust. Normal steel material. No stainless. I put a flex hose at the pickup end bending to the bottom an by that sucking most dust and water out. A agressive filter will collect it before normal fuelfilter arrangement. During motoring this will polish the fuel and discharge water and biogrowth. Rebuild to stainless tanks..not possible without enourmos work. We must have agressive filters to avoid clogging by the bad dieselquality we have here in Scandinavia.
To much biodiesel!

PostPosted: Sat Mar 16, 2013 3:54 pm
by warmrain
You may want to consider a fuel polishing arrangement as is done on powerboats. You may also want to consider a dual filter arrangement and a vacuum gauge so that in the event a filter become clogged you can switch easily to the spare filter. Consider also periodically having all the fuel pumped out of the boat, filtered and returned. We've done this only once in 20 years in the USA, but there was 15 gallons of sludge removed from a 80 gallon tank.

PostPosted: Wed Mar 27, 2013 8:59 am
by edelweiss
Steve do they do that pump out in the marina or do you have to be hauled out? Do you recal the company you used?


PostPosted: Wed Mar 27, 2013 1:50 pm
by warmrain
We used a local company, I don't remember who. I just searched google I think for a fuel polishing or cleaning company. THey came to us on Bainbridge Island, it is cheaper if you go to them. You do not need to haul. You will want to be prepared with an inspection plate. 8" is better than 6" if you have room. Theywill pump all the fuel out, steam clean the tank. dry the tank and pass the fuel through a 1 micron filter back into the boat. There are excellent fuel inspection plates available that you can install easily in the stainless steel cover of the tank. I regular hole saw works fine.

Re: Black Iron Fuel Tanks

PostPosted: Thu Nov 28, 2013 3:04 pm
by catalysis
We are contemplating a Hansa built 33 and would like to know if the water and fuel tanks are removable and if they are constructed of stainless steel.
Thanks for your help.
Paul and Maureen

Re: Black Iron Fuel Tanks

PostPosted: Tue Dec 03, 2013 12:28 am
by warmrain
The 2 water, one fuel and one holding tank are fiberglass and they are built into the keel; they are integral to the keel. They are not removable, they have stainless steel lids, that are impractically removable (installation of inspection places recommended). The advantage of their location is the do not effect the trim of the vessel port to starboard, nor do they consume the storage space under the settee. In the 26 years we have owned and lived aboard Warmrain (since she was new), the tanks have been trouble free.