Should I fear steel tanks?

[Nick F]

I see a number of people preferring top-draw fuel take-offs on the premise that this reduces the risk of fuel spillage from a leak in the fuel piping between tank and engine. Bear in mind that, if the leak in the fuel piping is below the fuel surface level in the tank, the fuel will also spill from a top-draw due to siphoning. The top-draw is not giving you the protection you think (unless your tanks are below your engine).

As you might have guessed, I am in favour of bottom-draw in large bore piping to get the crud and water out of the tank and into the primary filter/separators.

Nick

 

[dutch-barge]

well our boat has steel tanks fitted in 1930 and they are still good..

 

[Tator]

Our top feed/fill steel tanks are 43 years old with no problems or signs of rust. In 16 years and thousands of engine hours of use, I've never had water in my Racor. I dip the tanks every couple of years with a dowel and water detecting putty and it has never shown an indication of water in the bottom of the tank nor any crud. The tanks are mounted on fore and aft fiberglass rails. Because the salon is full width, there is not many ways for water to leak on them from above.

Tator

 

[CarlF]

Is there any recent survey of the boat? If not, I wouldn’t go any farther in negotiations without a surveyor looking at the tanks. Won’t cost much if you tell the surveyor to only look at the tanks for now.

 

[Sieben]

Hi all
I am new to the forum and Sadly, between trawlers.
In an effort to rectify this situation I am negotiating on a 1998 N46. As it turns out, this boat has steel tanks (pre Hull 68) and I am wondering how concerned I should be.
In an effort to be proactive can anyone offer any information on dealing with corroded tanks on this model?
Can they be removed through the salon floor and cockpit door (after removing the engine of course)?
Are there any reliable methods of repairing/treating the tanks in place?
What would a ball park figure be to replace the tanks on this boat?

Thanks in advance.

Hi there. We currently own a 1985 Passport 42 sailboat. Built in Taiwan. Tanks are fiber glassed over the steel. The usual issues regarding rust or sediment are condensation getting into the tanks. Or deck leaks from the fill following down to the top of the tank and rotting the fitting. Our boat has not had an issue. Some both power and sail of this era have.

Keep them "pressed" full with fuel especially in the winter. Fuel oil prevents rust. Drain off the bottoms. We have bottom drains and top fuel pickup. Some owners in our group have had a pin hole rusted at the weld seams. Some members of our group used an aircraft sealant made for tanks to seal all the seams and to coat the interior of fuel tanks in airplanes. This was done to a few leaking tanks which were on 1980' boats made of mild steel. Worked successfully with no loss of volume.

From a forum member from our group:

"They had some pitting too in the bottom of the tank where water had sat and a fairly large hole in one of the corners. So I first had used JB weld to patch the known hole in the corner where I could stick a screwdriver through. I was worried about longevity because the tank is the one in the keel with both sides glassed to the hull so likely to flex and work some.

I used two different 3M products, I'm not sure exactly which ones they were. I think the letter is for viscosity with A being the thinner and B being thicker.

The first was thick like a caulk which i used to seal all the seams like this:
https://www.skygeek.com/3m-aerospace-ac-236-class-b-non-sag-polysulfide-fuel-tank-sealant.html

The second was a bit thinner, brushable, but self levelling which I used to coat the insides.
https://www.skygeek.com/3m-aerospace-ac-350-a-2-gray-sealant-2-oz-kit.html

Also, I could only get to one side of the tank because of the baffle, so I had to cut a hole in the top and add an inspection plate to the other side.

I still want to do my other tanks at some point as a preemptive solution."

Hope this helps one with a leaky steel tank.

John

 

[High Wire]

My experience from my 1986 Phoenix 29 was outright scary. In 2000 my two 80 gallon aluminum main tanks were corroded badly. The ground connection tabs completely disintegrated. The outside surface was covered in powdery aluminum oxide. I also had two saddle tanks that looked new and a center line tank that looked new but completely obstructed access to vital things like shaft packings, seacocks and such. I decided to replace the mains and all of the fuel hoses. The saddle tanks needed to come out first before the mains. Long story short the perfect looking saddle tanks had holes in the bottom that a pencil would fit though under the glued on neoprene strips installed by Phoenix when constructed. The aluminum transformed into a gray tooth paste looking substance on the bottoms of all of the tanks. All five tanks contained gasoline prior to the replacement job and never indicated any leakage. The thoughts of water and sludge common in an aluminum diesel fuel tank is a no-go for me. Good luck.
______________

 

[MVDarlin]

I had my black iron 300gal (2) tanks cleaned and inspects in my 1982 Ocean Alexander 2 years ago. A hole was cut for access. 5 gal of bio goo gunk was removed from each tank. Other than that they tanks were fine. Keep them full, otherwise condensation will cause water to collect in the tank.

 

[SteveK]

It seems as if tanks may fail sooner on lack of use. If the water is left in the tank as opposed to separated in the filter. So low overall engine hours on the life of the boat causes tank failure. Never mind, Just pondering a thought here.

 

[mickand]

I have 40 year old steel tanks with no top rot.
Last year I took off one of the large inspection ports on one tank and went in with an endoscope to find a surprisingly clean tank with no obvious issues.
I've been using Diesel-Shok in my fuel for the last six years and it seems to be paying off.
Diesel-Shok is sourced from USA Fuel Service and it holds any water in suspension within the fuel.

 

[rolomart3]

Perhaps it is possible to use a bladder diesel tank from IPI as a liner inside the corroded steel tanks. These bladder diesel thanks can be custom made to fit and are military grade. Then, there is no need to replace or break anything in the boat. The only thing needed is an opening in the current metal tanks to insert the bladders.
Such an arrangement would make possible to remove the bladders to clean outside the boat or even replacement.
It would really take out all fear of steel tanks. More important, it would reduce a bit the fear of most marine pleasure boat manufacturers.

 

[JESSEDIVER49]

Should I fear Steel tanks

Not familiar with the N46 but generally, a good boat surveyor should be able to inspect and advise on the tanks. Eight years ago I bought a '84 Grand Banks 42 with its original steel tanks. The surveyor found corrosion issues on the tops of both tanks below the fill tubes where salt water found its way through compromised deck seals. When I asked how to fix this, he said "replacement". The seller gave me a price reduction and then some to cover replacement costs. It all turned out well. I went aluminum.

 

[sunchaser]

The surveyor found corrosion issues on the tops of both tanks below the fill tubes where salt water found its way through compromised deck seals. When I asked how to fix this, he said "replacement".

Jesse
Does the vessel have teak decks?. Even if not screwed down, deck fills through teak can prove troublesome in making a good seal with fill tubes. I know an ex GB dealer who said a good annual cleaning of tank tops was helpful in this regard. The same may well apply to your Al tanks.

 

[JESSEDIVER49]

Hi Sunchaser,
Yes, my deck is teak over fiberglass. I re-sealed where the fill flange meets the teak deck. That is where I was told by the surveyor the infiltration occurred. I also routinely check the area on top of my tanks to make sure there's no excessive oxidation. Don't know how to get new tanks in a N46 other than cutting a section of the hull but for the GB42, my tank guy designed 2 stacked tanks for each side and was able to get them through the salon door and into place by moving only the gen-set forward. It was still a labor intensive project.