Who has had to deal with leaking fuel tanks?

[Steve91T]

In a few days I’m dragging the family to the Keys to look at a 47’ 1988 Marine Trader with, most likely, original tanks.

So who has had to deal with leaking tanks? How old was your boat? What did you do to resolve the issue? What did the cost and down time end up being?

The solutions that I’ve read about that interest me is cutting the tops off and either installing several much smaller plastic tanks or fuel bladders plumbed together.

Just want to know what we need to prepare for.

Thanks guys,
Steve

 

[swampu]

I had to pull all of my tanks (4) 250 gallon. 2 had to be rebuilt 5k and two had to be patched and pressure tested, $2,500.00

 

[AusCan]

When I first looked at my 35 year old boat, there was a slight diesel odour but no obvious leakage. The surveyor didn't mention anything, but I didn't specifically ask him about the fuel tanks. The tanks were stainless and looked fine visually. The bilge was somewhat dirty and stained, but I put it down to just being an old boat.

After a few weeks I noticed there was always a sheen on any water that collected in the bilge. Over the next few months the sheen became a thin layer of diesel. The source of the fuel leak wasn't obvious. I checked fuel hoses and fittings, hoping to find a cheap fix. I contorted my body to look at all sides of both tanks. Still no leak found, and no inspection hatches on the tanks..

After about a year, I was sucking about a gallon of diesel out of the bilge every month. I still wasn't even 100% sure if it was a tank leaking or which one it was. There seemed to be a light film of diesel everywhere.

Then one day I was checking the oil on the old raw water cooled Volvo. The oily was white and frothy. Now the action plan was obvious. I pulled the engine, and pulled out the tank that I thought was the leaky culprit. It just barely fit out of the hatch. There was a very minor leak in the centre of the bottom, which became much worse after cleaning the tank.

I pulled the other tank as well. It didn't appear to be leaking until I cleaned it. Without the 1/2" of sediment this tank also started leaking badly.

I brought both tanks down to the local stainless steel fabricator for a repair quote, and he wasn't keen on patching them up. He quoted $1400 for fabricating two new 120 litre tanks.

For me it was 2 days to pull the engine, a week to pull the tanks, fit new ones and plumb them up, about two weeks to adapt the engine mount supports etc for the new engine, then about 2 days to fit the new engine.
A professional would have been faster, but I did mine on my own with some help from my son.

 

[Bay Pelican]

Removed two 350 gallon tanks from a Krogen 42, replaced with four 110 gallon tanks. Remember any substitute for new tanks will affect the eventual resale.

Cost was Eastern Caribbean (high) so it is not comparable.

 

[Larry M]

We replaced ours in 2016. At the same time we rebuilt the engine and running gear plus rehabbed the engine room. Here are the numbers and a thread of what we did.

http://www.trawlerforum.com/forums/s32/krogen-42-fuel-tank-replacement-28204-14.html

Tank Construction: Includes tax, no transportation $10,529
Engine/Running Gear Rebuild: no transportation costs $12,558
Boat Yard: haul/block/launch, fork lift, crane, some tools and minor parts $4,562
Subcontract Labor: 86 hours $6,240
Stuff: Perf al panels, plywood, parts, more tools, hose, etc $3,800

Ouch $37,689

We were under budget on the subcontract labor but that doesn't take into account the 400 plus hours that Lena and I put in. It's difficult to say what costs were specifically for the tank replacement. The engine rebuild is easy to separate out, but not everything is as cut and dry. We had to replace the existing ceiling and wall panels. There was too much damage trying to remove and then reuse them. How do you do this job and not rebuild/replace the thru-hulls, hoses and some wiring? Another area that took additional resources was the re-configuring of the engine room. With each tank 22” shorter, we removed or modified nine mounting platforms. We could have used the existing ones and saved at least a week but how would it have looked?

Would we do the same thing again? Probably. We didn't feel we had many alternatives. A band-aid approach could have sufficed, but would have been hard to live/cruise with. We also considered the option of handing the project over to someone. We talked to one local yard (Lambs) before hand. They have the ability and resources but at $90/hour and no owner involvement, we estimated the project would have been north of $70,000.

 

[alormaria]

Summer of 1995 tank replacement ran me about $8000. The yard did everything. I just signed the check.



Pulled the engine/trans and both tanks intact. Everything fit through the saloon door. Entire saloon covered in padded cardboard. De-greased engine room and painted. All new hoses and clamps on everything.



Like it never even happened.

 

[tiltrider1]

The first thing I do when looking at a potential new boat? Where are the fuel tanks and what is it going to take to replace them.

With my last boat I had to remove everything from the engine room(engines, generator, batteries, pumps, blowers,etc) just to get the tanks out. New tanks cost me $3000 for two 200 gallon tanks. Spent another $1000 in misc. Did all the work myself. Took me 3 weeks. This was in 2008.

My current boat has center line tanks. If I ever need to replace them it will be a weekend project.

 

[Steve91T]

Just curious why you guys didn’t cut the top off the tanks and install plastic tanks? Is that not a very good option?

 

[Larry M]

Just curious why you guys didn’t cut the top off the tanks and install plastic tanks? Is that not a very good option?

A lot depends on how the tanks are installed, shape of the tanks, capacity and access. Our tanks were 350 gallon each. They conform to the side of the hull and there is only about 4” of clearance at the top. As it was we still lost capacity. If the tanks are rectangular or square, that would make things easier.

 

[Giggitoni]

http://www.trawlerforum.com/forums/s6/replaced-fuel-tanks-26430.html

Been there, done that!

 

[Steve91T]

I’m all about doing things right, but for a fraction of the cost, I’d be all about it. I don’t think I’ll mind loosing some capacity. This thing holds 600 gallons of diesel...I just don’t need that much.

What age were the boats that needed tanks?
We really think this would be our forever boat. Our plan would be to enjoy it for a few years and eventually get it to Willmington, NC which is a 3 1/2 hr drive. Then we’d tackle the tanks before they start leaking. That way we choose when to tackle them when it’s convienient for us.

 

[Airstream345]

http://www.trawlerforum.com/forums/s6/replaced-fuel-tanks-26430.html

Been there, done that!

Great post and a clever solution (stacked tanks).

Back to the OP, if you have reason to believe it's an issue on this boat pre-survey then perhaps it's a deeper point of survey inspection and negotiation.

Shortly after buying our 37 yo trawler I went aboard after a week away and smelled the dreaded diesel smell. Not a whiff, a strong diesel smell and then found fuel in the bilge. My heart dropped.

Imagine my relief to find out it was a failure in the hydronic heater fuel system which was easily corrected. Once the bilge was cleaned and scrubbed it smelled better than the day we took delivery.

Still, I know my day will come so I read all tank replacement threads with great interest and trepidation.

 

[Steve91T]

http://www.trawlerforum.com/forums/s6/replaced-fuel-tanks-26430.html

Been there, done that!

That was a a great thread, just read the whole thing.

One thing that I didn’t realize was “just cutting out the old tanks” isn’t so easy!


I’ll tell you what, I’m going to make sure I check out the tanks on this boat as well as I can. I really don’t want to be the last one standing.

Another thing that might be worth it is to jack the tanks up (after it’s mine, obviously) and make sure there isn’t any place to trap moisture. Maybe I’ll be able to take care of it and stop any rust.

 

[Comodave]

A common place for rusting is below the deck filler fitting. The caulking goes bad and water drips onto the top of the tank. The tank should also have a non absorbant spacers under the tank so water under the tank can dry out. The spacers should be caulked to the tank so no water can get between the spacer and the tank. There should be inspection ports in the tanks.

 

[Giggitoni]

If the tanks are kept dry and coated on the outside and water eliminated from the inside, the tanks will outlive us!

 

[jungpeter]

Hi Steve91T,

As you're obviously aware, there are a vast variety of recreational power boats afloat, and thus a vast variety of fuel tank replacement issues extent in those boats. The lack of enthusiasm in both the professional and amateur participants in such a venture to put (usually) painful and very expensive lessons into writing once the replacement(s) are complete means there are few true case studies of fuel tank replacement available. You will find, particularly in an open yachting forum such as this one, an equally vast array of anecdotal evidence of tank replacement, ranging from "Piece of cake. Did it myself in a weekend." to "Gaaakkkk. Took my entire retirement savings. I'm selling the boat and moving to Iowa".

As an unfortunate veteran of both water AND fuel tank replacements on a previous boat, I can only offer the following attachment.

While I also have created a case study for the replacement of my water tanks, it's unfortunately too large to post to this forum. If you'd care to private message me, perhaps I can send it along offline.

In way of my opinion (YMMV!), any boat >20 years old has a financial and emotional time bomb (fuel tanks) in it's bowls. Best to keep your eyes wide open. Danger, danger!!!!

Regards,

Pete

 

[Woodland Hills]

Or you could avoid the issue entirely and buy a boat with all fiberglass tanks..... It may cost more initially but it also might end up cheaper in the long run.

 

[Steve91T]

Is there such thing as some sort of insurance for normal wear and tear of a system like fuel tanks?

 

[Heron]

Just happened to a friend of mine with a 2002 Shannon 36. Aluminum tanks which are normally not problematic, but Shannon foamed the installation which is apparently a no no. Due to (lack of) access issues a 4x7 foot chunk had to be cut out of side of the boat to remove the tank. Problem was only a perforated bottom, so a local fabricator cut it off and welded in a new bottom. In the end, the fiberglass work and gel coat match was spectacular but no idea on how many boat units this cost. You cannot tell it was done...You can bet it was not cheap..

 

[Lepke]

Except for yachts, most fuel tanks are mild steel because they're cheaper to make if part of the hull. With proper care they last the life of a boat or ship. People use to diesel engines know if the fuel isn't used in a timely fashion, conditioners need to be added. Yacht tanks are usually stainless because most yachties only think of their tanks after a problem. If the fuel is going to sit for months, the stabilization and biocides included at the refinery have evaporated or lost their potency. I add a conditioner every fueling regardless of how fast I expect to use the fuel. My main tanks are 1942 mild steel and clean, no sludge, no water. I know because I've been inside.
It's difficult to repair a leaking tank. Usually the entire section is thin and welding just makes more leaks. There are tank coatings made of epoxy or rubber like material that will seal a leaky tank. But the tank needs to be clean metal first.
Using a proper conditioner/biocide will slowly clean sludge out of dirty tanks, but may require more frequent filter changes.
My suggestion is to use a decent conditioner/biocide to get the tanks clean. With the sludge and water gone, any corrosion stops.

 

[Steve91T]

Can’t something like this be mounted in between the baffles of the original tanks?

This is just an example of what I’m talking about.


https://greatlakesskipper.com/moeller-marine-boat-fuel-tank-ft001546bd-crosslink-poly-46-gallon

Just under 200 gallons for less than $1500.

 

[tiltrider1]

Every boat is different. When I replaced fuel tanks the boat was 35 years old. The tanks were aluminum, they sat on a flat surface with a layer of a tarred paper between the tank and surface. Problem was after 35 years the boat had developed many unknown rain leaks. Water managed to run down the side of the tank and worked its way between the tank and the water barrier. Result, bottom rotted out.

Now as for cutting the top off the tank. Tank would have need removing to insert a plastic tank, at that point the cost of a new tank was not vary significant.

In both my aviation world and my car racing world we use fuel cells. Fuel cells are like bladders with foam inside to act as baffles. I could hav made a 1 foot radius hole in the side of the tank and stuffed a custom made fuel cell in. Problem is the cost of a two hundred gallon fuel cell was astronomical and I need two.

 

[Deckape]

replaced both tanks on my Jefferson 45.started leaking after I had tanks cleaned after fuel polishing showed lots of crud in tank.Think picking a scrab inside tank then leaking thru. Welder was able to repair first leak near edge.next leak was under on bottom. Set up Aframe in saloon lifted engine over other while putting in tank, same with other. had to reduce size so tanks would fit thru rear window. did replacement in two weeks with help from friends that I gave fuel to. lots of work but saved big $$$$$. look closely at edges and wipe hand/rag on edges and floor near tanks. there will be a wet trail from tanks to bilge. boat is now for sale if you don't buy that one.

 

[Simi 60]

A common place for rusting is below the deck filler fitting. The caulking goes bad and water drips onto the top of the tank. The tank should also have a non absorbant spacers under the tank so water under the tank can dry out. .

Easier solution is to have fillers in the cabin sides.
Ours are about 3 ft up and hoses hidden in cupboards.

 

[Steve91T]

replaced both tanks on my Jefferson 45.started leaking after I had tanks cleaned after fuel polishing showed lots of crud in tank.Think picking a scrab inside tank then leaking thru. Welder was able to repair first leak near edge.next leak was under on bottom. Set up Aframe in saloon lifted engine over other while putting in tank, same with other. had to reduce size so tanks would fit thru rear window. did replacement in two weeks with help from friends that I gave fuel to. lots of work but saved big $$$$$. look closely at edges and wipe hand/rag on edges and floor near tanks. there will be a wet trail from tanks to bilge. boat is now for sale if you don't buy that one.

Can you send me more info for your boat?

 

[Deckape]

listed with Curtis and stokes, on yacthworld 1986 45"Jefferson " Silver Gift" twin perkins , 7.5 gen in fort Lauderdale now.

 

[FOG]

I replaced a 100 gallon tank on our 1981 Prairie 36. You can read the detail here starting with post #20. http://www.trawlerforum.com/forums/s34/prairie-36-improvements-25815.html

Total cost was just over $6,000 including $900 for the new aluminum tank.

 

[Steve91T]

listed with Curtis and stokes, on yacthworld 1986 45"Jefferson " Silver Gift" twin perkins , 7.5 gen in fort Lauderdale now.

I just searched yatchworld and Curtis and Stokes and couldn’t find it.

 

[Comodave]

I just searched yatchworld and Curtis and Stokes and couldn’t find it.

I just found it on Yachtworld. Advanced search, Jefferson, 45’ to 45’, 1986 to 1986 and it pulled up 2 boats, one of which is the one in question. Good luck.

 

[Steve91T]

I just found it on Yachtworld. Advanced search, Jefferson, 45’ to 45’, 1986 to 1986 and it pulled up 2 boats, one of which is the one in question. Good luck.

The advanced search did it. Not sure why but it did.