new diesel fuel tank

[bjor]

Hi everybody,

I have an old leaky diesel tank that must be replaced (se pictures). Does anyone in this forum know if this kind of tank is mass-produced by anyone, or if this is a custom diesel tank that must be custom made.

Grateful for any suggestions / ideas for how to replace the old tank.

[Spot]

Hello Bjor,
Does the tank come out of the boat now or is it still some work?
Which material - steel, alu, ?
It might be worth having it repaired and maybe adding an inspection hole and cover.
I understand if you would rather have a new one.
At an old job of mine we could have made a new one after work.
I know there are a couple places in the US but I imagine you do not want to wait and pay shipping.

For the SI-unit challenged:
10 cm= 3 & 15/16"
20 cm= 7 & 7/8"
40 cm= 15 & 3/4"
60 cm= 23 & 5/8"

[tkeithlu]

You are not likely to find that tank unless the boat is still in production, or at least the manufacturer is. That's a long shot at best.

It appears to be aluminum, right?

Given the shape, the leaks are likely to be along that bottom seam, where water could accumulate in the tank. That means that if you can completely clean it out, adding an opening (or two) in the top, you have the option of sealing the tank from the inside with epoxy or similar. Don't try to seal it from the outside.

All that will work better if you remove the tank from the boat.

Consider this route. Fabrication of a new tank is going to be difficult and expensive, and only a tiny part of it is actually damaged.

[wsmurdoch]

We found a leak in our aluminum diesel fuel tank while in the Bahamas, We repaired the tank with epoxy and glass cloth applied over the outside of the tank. https://irish-eyes-to-the-bahamas.blogspot.com/2018/03/ The field repair held until we returned to the USA where we found a fabricator who had CAD/CAM for our oddly shaped tank and built us a replacement. When we removed the repaired tank, the repair was still sound. https://irish-eyes-to-the-bahamas.blogspot.com/2019/02/

[bjor]

The tank is steel, and not marine quality. I agree that repair should be considered before buying a new, but I need to get the tank out first to assess the condition. The idea of repairing from inside with epoxy was interesting. However, I foresee it could be difficult to apply it.

[Tsuru]

I priced a custom aluminum diesel tank for our boat and the quote wasn’t to bad.
https://www.sptanks.com
I haven’t ordered yet so I can’t really endorse the company, but in general it is a tested certified tank.
The odd size adds to the cost but it's not a problem.
Good luck,

[Clivevon]

I used this firm fo a new tank some years back - very helpful & no problems.

[Clivevon]

Sorry ..https://www.shop4tanks.co.uk/

[Squanderbucks]

Your existing tank has all flat surfaces and could be easily duplicated in most any material. I would recommend getting it totally out of the boat for replacement. Trying to just measure it up and have someone make is likely to not fit back into your curved space. Off a few degrees and it will bind somewhere.
For diesel my favorite material is fiberglass, second choice is aluminum. Last is Stainless steel.

Fiberglass is very forgiving and repairable or allows future modification with normal shop tools. Also it never rust, corrodes, or gets pinholes if properly sealed when made. “Fiberglass is forever”.

Several methods. Build a mold and make it then throw away the mold. 2. Build it out of foam or Cousa board and fiberglass it inside and out. No mold. Thicker but easier for some.

Personally I prefer to make a mold out of Masonite and 1x2’s, wax it up and Mamet the tank. Same for a top and bond together.
These are lighter and less bulky due to thinner walls.

[John Hornung]

Originally Posted by bjor

The tank is steel, and not marine quality. I agree that repair should be considered before buying a new, but I need to get the tank out first to assess the condition. The idea of repairing from inside with epoxy was interesting. However, I foresee it could be difficult to apply it.

Cut access holes in top of tank large enough to work through, with good light epoxy all most dependent seams with epoxy, then dye test for leaks!

[stormalong]

I am in the replace it camp. You never know how long a fix will last or another location fails. Since you can remove the tank bring it to the fabricator for replication.

My aluminum tank is 35 years old and still good (knock wood) So I like aluminum.

I see that the OP is in the Netherlands - a country well known for quality steel boats. I would think that they have many skilled tank fabricators as well.

[Manateeman]

Please replace the tank. Add the cost of inspection plates, cleaning it perfectly and epoxy. Might this work? Yes, but if it fails you have diesel in the bilge.
More money and time. If your pump turns on and discharges diesel or even mostly water and diesel, and you are inspected by the authorities, the cost of a new tank will look small by comparison.
USCG boarding parties now routinely look into the bilge They say they want to make sure you are not sinking. Oil in the bilge and an automatic pump and they will write you a ticket. In Norway, they ask to see the bilge to make sure it’s not filled with bottles of undeclared scotch whiskey...LOL. Same search for oil in the bilge, just steeper fines.
Replacing the tank adds to the value of your boat...let’s you sleep better in a storm when a leaks can turn the boat into a skating rink in which you cannot breath. Diesel fumes turn everybody green.
Once you have a new tank, buy a Bio Sock , keep your bilges clean and you and your crew will be healthier. So too will be the oceans.
Happy trails to you.
Captain Mark and his manatee crew .

[Pete7]

Originally Posted by Manateeman

Please replace the tank. Add the cost of inspection plates, cleaning it perfectly and epoxy. Might this work? Yes, but if it fails you have diesel in the bilge..

Agreed, can't imagine the amount of work needed to clean up an old diesel tank to a standard that epoxy will stick and stay stuck permanently. You really don't want it breaking up and blocking the outlet pipe for example.

The Jay Wolfe people have a good rep on YBW.

Pete

[billgewater]

Lots of good advice so far.

Have you considered plastic diesel tanks? They are made by a rotation method or by fabrication from sheet material that is welded. No rust/corrosion. Ever. Most companies offer a 15 or 20 year warranty. Used around farms in profusion. Probably heavier than alloy tanks.

Then there are "bladder" tanks. Again these can be purchased off the shelf or fabricated.
I have seen a situation where an installed rusting steel diesel tank simply had the top cut off in situ and two bladder tanks were installed inside the tank. One on either side of the single center baffle. These bladder tanks were on a commercial fishing vessel and as far as I know are still there without problems after 30 years.
Pricey, but for a badly corroded tank or one with leaking weld joints or other issues, the bladder tanks may be a useful idea. And you can easily do it all yourself. No resins, no fabrication.
I understand that a big advantage of bladder tanks is that they look after your fuel by not allowing any air (with associated moisture) to be present in the bladder. Minimize moisture and minimize fuel "decay".

[joelhemington]

Originally Posted by bjor

Hi everybody,

I have an old leaky diesel tank that must be replaced (se pictures). Does anyone in this forum know if this kind of tank is mass-produced by anyone, or if this is a custom diesel tank that must be custom made.

Grateful for any suggestions / ideas for how to replace the old tank.


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How much fuel do you need? It could be possible to find a slightly smaller mass produced tank "off the shelf" that would fit the space and surely be a lot cheaper than having something fabricated. Maybe even a bladder though I think a real tank would be cheaper in the long run.