Taiwanese trawler fuel tank

I know the average life expectancy of a steel fuel tank in a saltwater environment is approximately 20 years. Does the same hold true for a freshwater trawler?

Greetings,
Mr. t. I think it's safe to say that the greater number of fuel tanks rust out from the top due to deck leaks which is most probably fresh water (rain/wash downs). The presence of salt in both the atmosphere and in on board splashes will exacerbate any top tank rusting. So my GUESS is freshwater boats should suffer less rusting problems.

IF the deck leaks are held in check and water is kept out of the fuel, black iron tanks can last the life of the boat.

traveller said:

I know the average life expectancy of a steel fuel tank in a saltwater environment is approximately 20 years.

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This is news to those that have 40+ year old steel tanks and are still doing well. RT nailed it, whether salt or fresh water keep the fresh water from getting onto the tank. Inside the tank, now that is laborious story.

There are thousands of 40+ year old mild steel tanks. As mentioned before keep the exterior of the tank dry and rust prevention maintenance. Connecting the tank to the zink loop helps protect the tank.

Also reduce the moisture water in the tank by using turning the fuel, keeping the tank warm, and additives to prevent separate and absorb moisture water into the fuel. Fuel polishing helps as it clean and mix the fuel up. Lastly changing the trim of the boat so stuff does not settle in the same place.

So to have a tank last it has to be maintained.

Phil Fill said:

Also reduce the moisture water in the tank by using turning the fuel, keeping the tank warm, and additives to prevent separate and absorb moisture water into the fuel.

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Phil; I know, or think, you were trying to say something there and the posting process probably got in the way. Can you restate it so I can understand what you meant by turning the fuel?

He guessing he means using the fuel. Not letting it sit around for long periods.

Capt.Bill11 said:

He guessing he means using the fuel. Not letting it sit around for long periods.

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Thanks, Bill. Going back and reading it again, I see a comma would have made my feeble brain see it differently.

Thanks for all of your very useful replies. Looking at a freshwater trawler and this information is a big help.

Hawgwash said:

Thanks, Bill. Going back and reading it again, I see a comma would have made my feeble brain see it differently.

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I know the feeling.

"Using/turning over"

Averages really mean nothing. Just like talking about engine life. Maintenance and upkeep override time and each boat is different. A 40 year old tank can be in better condition than a 5 year old.

BandB, is that a boat or one of Michael Jordans tennis shoes

kulas44 said:

BandB, is that a boat or one of Michael Jordans tennis shoes

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Darn..you weren't supposed to know I had a pair of his tennis shoes. lol

A pair !!!!, dang you are livin large.

kulas44 said:

A pair !!!!, dang you are livin large.

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Actually no shoes. I was never a sports apparel or autograph collector.

Oh, my bad, I thought you meant you had a pair of those boats

traveller said:

I know the average life expectancy of a steel fuel tank in a saltwater environment is approximately 20 years. Does the same hold true for a freshwater trawler?

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Actually it can be as short as 15 years. My trawler had been run on Lake Michigan for it's first 15 years. The original mild steel tanks let go the next year.

If any one says 'they all smell like that', you tell them ' only when they are leaking'. Diesel boat's tanks and engine room do not smell of diesel. If there is a spill, it's wiped up and the smell leaves. Lingering odors point to a problem.

Check all the bottom corners of the tanks, check the deck fills' o-rings, check the tops of the tanks, check how they are mounted. Take a fuel sample from the bottom of the tank - either by disconnecting the balance tube or by a tube lowered to the bottom. You need to check for water and rust. If possible use one of those small TV things to examine the bottom corners of the tanks when they are empty. (transfer the fuel to the other one)

If you think all this sounds like a pain in the a$$, let me tell you having the 16 year old tanks in your new trawler drop 300 gallons of diesel into the bilge is even a bigger PIA.

It seems to me that old rusty steel tanks are the number one major problem on older boats, Taiwanese or otherwise. Am I wrong ?

I cut mine out because of all the surface rust after 26 years....they had another 20 years in them no sweat....

The question is...how do you know? You don't without some fancy investigation.

For me...getting rid of them was no big deal as I wanted smaller tanks with more storage in the engine room...but the tanks would have lasted years and years longer despite the surface rust.

Greetings,
Mr. 44. Rather, I think it is much truer to say water leaks "...are the number one major problem on older boats, Taiwanese or otherwise." Sometimes, more often than not, steel fuel tanks just happen to be in the line of fire.

Steel tanks still make the best replacement , and are still Std on the high end Euro boats.

Fix the deck leaks , and you wont have to touch the tanks.

RT Firefly said:

Greetings,
Mr. 44. Rather, I think it is much truer to say water leaks "...are the number one major problem on older boats, Taiwanese or otherwise." Sometimes, more often than not, steel fuel tanks just happen to be in the line of fire.

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Yep. It would seem that some here are in denial and blame their steel fuel tank's woes on the material used rather than following the basics as oft mentioned on this thread. It starts with boat fuel tank related construction techniques and design and all too often goes downhill from there ------------

RT Firefly said:

Greetings,
Mr. t. I think it's safe to say that the greater number of fuel tanks rust out from the top due to deck leaks which is most probably fresh water (rain/wash downs).

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...or from standing water between the tank and the stringer. According to the PO, this what happened on our boat. Failed welds from vibration, perhaps contributes to the problem.


Jim
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I would add that any new metal tanks, any reconditioned tanks going in that it is VERY cheap insurance to cover with light grade glass cloth and a couple of coats of epoxy. Be sure all screws securing wood or whatever material securing the tanks are well counter sunk and sealed.

I pulled my 110 (2) tanks from my Mainship 34 Mk 1 and everywhere there was a screw securing the bunk there were pits in the Aluminum, none were touching metal to metal. The humidity let the wood conduct just enough I guess.

I sanded and sealed the tanks sanded and sealed the bunks with glass-resin then 5200 the tanks in place, with accessible access holes to each baffled (3 each) for future clean out.

traveller said:

I know the average life expectancy of a steel fuel tank in a saltwater environment is approximately 20 years. Does the same hold true for a freshwater trawler?

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Please don't tell my 32 year old tanks this!

Seems that it is all up to the install and keeping them dry as many have mentioned above. My survey ten years ago showed them to be healthy and no issues. The tanks on my Ocean Alexander are wrapped in insulation which I imagine cuts down on condensation.

Mule said:

I would add that any new metal tanks, any reconditioned tanks going in that it is VERY cheap insurance to cover with light grade glass cloth and a couple of coats of epoxy. Be sure all screws securing wood or whatever material securing the tanks are well counter sunk and sealed.

I pulled my 110 (2) tanks from my Mainship 34 Mk 1 and everywhere there was a screw securing the bunk there were pits in the Aluminum, none were touching metal to metal. The humidity let the wood conduct just enough I guess.

I sanded and sealed the tanks sanded and sealed the bunks with glass-resin then 5200 the tanks in place, with accessible access holes to each baffled (3 each) for future clean out.

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There is no way I would coat properly painted metal tanks with glass cloth. To much chance of the tank flexing and the glass cracking and/or pulling away from the metal. Then moisture could get in in between the glass and metal.

I'd much rather that they were properly painted and left with air space around them.

Capt.Bill11 said:

There is no way I would coat properly painted metal tanks with glass cloth. To much chance of the tank flexing and the glass cracking and/or pulling away from the metal. Then moisture could get in in between the glass and metal.

I'd much rather that they were properly painted and left with air space around them.

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especially if the epoxy lifts the paint off...could turn into a mess...

1. I sold the boat, so test results will not be known. 2. The cloth was the lightest out there. 3. They were bare unpainted aluminum. Guess we will never know.

Good for you Mule cause the new owner is gonna have to pay . I would think it very obvious that stainless (or worse bronze) screws into wood bunks that the tank rests on would be problematic. Glue down some rubber strips, its really is that simple.. Also rubber between the tie down straps and the tank, glued with 5200 to the straps, again super simple. And the inspection of steel fuel tanks wrapped with insulation would be a problem for me. How can you know,,, until they puke there contents into the bilge. False sence of security.

Well, if I did wrong I had no reason to believe it at the time. I have no idea where the boat is. I, at the time had planned on keeping it. There was seeping fuel through one of the pits caused by electrolysis. Lastly, just because you said I did wrong, does that necessarily make it so. The manufacturer certainly did not engineer the bunk system right, I did the best I could. So your implication I smugly handed off a problem to a future owner intentionally is certainly offensive and not factual. I did what I thought was right at the time.