Bad Fuel Tanks

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
"hardest part of putting a bladder in a steel tank is getting rid of the baffle...for me to cut the baffles out of my steel tank...I had to make many more cuts in the tank than just removing it.

just that labor alone starts to get close to just cutting the whole tank out."

True , but its a heck of a lot less labor and risk to install the bladder than remove the engine to get the NEW tank in place.

A huge tank replaced by 3 -4 plastic boxes for fuel would have the advantage to install and more important

all but 1 or 2 could be empty most times when extreme range has no value.
 
Every time the repair or replace fuel tanks issue is raised I comment that a boat owner needs to check with a broker about the effect of repaired tanks on the resale price.

Many times I have cautioned potential buyers that if they find a boat with 25+ year old mild steel tanks to assume the tanks will soon need replacing and reduce the price accordingly. A repair with epoxy is not the same as new tanks.

The problem for the seller is complicated, perhaps there is a buyer who will accept the repaired tanks and not discount. However, if the buyer discounts then he or she will discount more than the cost the original owner could have paid and give no discount for owner supplied labor. Thus the repair may end up costing more as the original owner pays for the repair and the eventual discount.

This is the gamble a owner with leaking tanks must face.
 
Many times I have cautioned potential buyers that if they find a boat with 25+ year old mild steel tanks to assume the tanks will soon need replacing and reduce the price accordingly./QUOTE]

This was the number one worry for us. Certainly the risks are greater with older tanks, but I think it's possible to allay the risk considerably by getting a service to pull the inspection ports and take a good look inside. We did that with our 29-year-old fiberglass-encapsulated tanks and were relieved to learn that they look like new inside (once the sludge was mucked out). We can see across the tops of the tanks to the inner hull and there are no water or rust stains anywhere with sound fiberglass decks above. Not a guarantee, of course, but we do sleep easier.

And lest we think leaking tanks are a problem exclusive to older boats, I was at a marina yesterday (no names to protect the owners from embarrassment), where the yard crew was scrambling to stop a tank leak in what they told me is a brand new steel-hulled trawler. Gorgeous boat but a seam just started leaking for no obvious reason. They pumped 30 gallons out of the bilge and presumably transferred the remaining diesel from the leaking tank to a sound one. The owners must be livid; but the boat was built offshore (not East Asia) and I'm not sure what recourse they'll have.
 
In my case removing the engine above the other to set the tank was my way. Had cutup old tank and removed. Put in aluminium tanks , fast forward 8 years and had a bad weld start leaking,so did it again with a boom lift at the yard. Came thru window and lifted engine,trans up and over while crew removed tank thru other side window to ground so welder could do repairs. Then same to put back in. A pain in the ass but can afford the boat/ repair but not the crazy prices that I got for someone else to do it. $30,000.00!!!!!!!
 
Hah, I just vacuumed the outside of the stbd tank for the second time since Ive had this boat. Seriously I can run the shop vac along the wall of the tank and load up on it, if only it was gold. I carried probably 40 pounds of rust flake to the dumpster. I reckon I have ,0001 metal and .005 of tank sealer left before it collapses. :)
 
As always this is a interesting subject. I note lots of good advice above, with lots of practical experience talking. But before going ahead in panic mode I think you should assess the real damage. In some cases I've removed the smaller damaged area and installed acess ports for the normal damage from leaky decks. I've never seen an hull panel removal look "right" after a year or so, the gelcoat ages differently. So you finish respraying at no small cost. The earlier GB's had cast steel tanks that made repairing difficult.
Severly damaged tanks we cut out, whipped the engine out install new tankand replace the engine. Some times installing 2 for one, the cost of breaching the hull or deck always seemed to add substanially to the cost. Would be nice to see some pictures drawings of the damage, to gain a further insight. I'm sure the rest of the forum, could supply more advice with extra information.
 
Last edited:
"hardest part of putting a bladder in a steel tank is getting rid of the baffle...for me to cut the baffles out of my steel tank...I had to make many more cuts in the tank than just removing it.

just that labor alone starts to get close to just cutting the whole tank out."

True , but its a heck of a lot less labor and risk to install the bladder than remove the engine to get the NEW tank in place.

I wonder how much you'd really save going with bladders? One off the shelf 200 gallon bladder is going to cost close to $1000.

And you might have to have one custom made to properly fit the old tank. Which could cost a lot more. Then there is the issue of how you're going to plumb it, since the bladder will collapse as the fuel is drawn out of it so the hoses have to move with the bladder.

You suggest this method all the time. Have you actually done it instead of replacing tanks with tanks? If so, how much did you save over installing new tanks?
 
"And you might have to have one custom made to properly fit the old tank. Which could cost a lot more."

In the larger sizes ALL the tanks are made "custom" so there is no price problem.

My use of bladders has been on NEW boats , where the space is fitted with 2 bladder tanks .

One for diesel, one for FW so the owner can chose which he prefers to have aboard.

Bahamas water is expensive , winter liveaboard diesel is heavy on a snow covered dock.
 
"And you might have to have one custom made to properly fit the old tank. Which could cost a lot more."

In the larger sizes ALL the tanks are made "custom" so there is no price problem.

I was talking about a bladder.

If you were replacing your old tanks with a bladder you might need/want to have a custom sized bladder made.
 
"I was talking about a bladder.

If you were replacing your old tanks with a bladder you might need/want to have a custom sized bladder made."

ME TOO! after a certain size OTS just doesn't work.

Esp if you wish to specify fill and vent size and location or the tank has an unusual shape.

Google shows

ATL Bladder Tanks - Collapsible Fuel & Water Tanks - atlinc.com‎

Adwww.atlinc.com/pillow.html‎

  1. 25 to 100,000 Gal (100-400,000 Ltr)
    Brands: Petro-Flex, FueLocker, Aqua-Flex, Chem-Flex
    Marine Fuel Bladders and Auxiliary Fuel Tanks



Search Results

ATL Fuel Bladders - Custom FueLocker Range Extension Tanks for ...

atlinc.com/custom-fuelocker-marine-fuel-bladders.html
ATL can build fully-collapsible CUSTOM fuel bladders for use in your vessel's existing live-wells, bait tanks, fish boxes, storage compartments These bladders ...



Marine Fuel Bladders and Auxiliary Fuel Tanks - Aero Tec Laboratories

atlinc.com/marine.html
ATL produces rubberized fabric bladder tanks in standard and custom sizes for offshore race boats, work boats, fishing boats, pleasure yachts, military ...



Marine Gas/Diesel/JP-8 Fuel Bladder Tanks and FueLockers for ...

atlinc.com/rangeextender.html
Collapsible gas/diesel auxiliary fuel bladders and pillow tanks for extending range of sportfishing ... Click Here for CUSTOM ATL Range Extension Bladders!
 
Bladders don't make a very efficient use of space. However if you're talking bladders why size them to your old tanks? If you're going to put bladder in your old tank you have to cut access into the tank, remove baffles and so on. Just cut out the old tanks and build boxes to contain the bladders. A lot less work.
 
"A lot less work."

Boxes can be built outside the boat and just taken apart enough to get in place.

Boxes also are less sensitive to mounting than tanks.
 
marine trader 38 fuel tanks

Ok, here is my plan i wanted to add to a thread that was already going. Im in the Fuel Buisness and how we fix aged underground UST's is to make entry to them and coat them with a product we call Chem shield 1185, funny enough this material can also be used for bottom jobs is general overkill for bottom jobs but it works well and ive seen applications for sealing leaking tanks go over 20 years.

plan is to make a hole in the end of the tank that we can get a roller in clear the tank and put this epoxy solution in.

To make a point once this is done correctly you will have a 60 mil tank built inside of another tank the steel will only be support for the new tank you have constructed on the interior.

Its important to note a few things , one being the pentration fittings will take some attention unless you go to a top down way of getting fuel out of it which isnt a bad idea. its also harder to get the tops the way the bottom is in the sense. cleaning the outside top and coating it would help with rusted tops but essintially you building a tub for fuel to sit in and it works well in all applications ive tried it on.

This will be the first boat fuel tank ive attempted this on and ill let you know how it goes.

Im pretty sure that it will be successfull something that ill practice initially is not filling the tanks 100% maybe run them up to 80 since we are not replacing the steel.

Im sure this will work and i dont understand coming from my background why this isnt common practice , i might be wrong and people may be using this im just blown away by all the threads stating they cut the boat open and screw with 40 year old fiberglass to me that sounds crazy , no way to match that stuff.

There may be in fact something that keeps this from being used. im pretty optimistic and i think it will work.

for referance the material we use is developed by a chemist for exactly this and if info is needed on it please PM me id be happy to share/aquire the material if someone is in the same boat.

the method is this , bondtitie 1101 applied directly to the steel 2 coats,

then between a 30-60mil coat of the chem shield 1185. you will have effectivly built your own fuel tank once this has been done. ive never seen this stuff fail

Private message if material is needed i do not think they sell to the public.

(edit) additionally , the piece you remove to get access, my contractors that do this coat the inside of the existing piece and the jb weld it back on have never seen them do it different , for my purpose i will probably build a flange of some sort with out welding maybe a ring with studs on it hadnt decided completely on that part or i may just coat the piece and do as my fellow contractors do and jb weld it back on seems improper but ive seen it in real world applications.
 
Last edited:
Sounds like a good plan for a open fuel tank . Most marine fuel tanks have baffles thru the tank to keep fuel from moving fore and aft as well as support . How will opening one end get between baffles ? And how would you close the opening ? Inspection plate ? Access would also be a problem unless you have removed tank from boat . When I did mine tanks ,engines were lifted with A-frame in saloon and moved over other one while new tank was installed . No cutting of hull sides . If I had to remove tank to do your coating process ,I would just cut old tank out and install new as I did . Hope it works in your case . Good luck .
 
There is always a business performing this service. Unfortunately they never seem to stick around long enough to be come well known.
 
If we hit baffles I'm going to cut them out and fab a lay in baffle ,

I probably should have explained that.

Looking at some of the removed tank pictures some of them I don't think have them at all.

Either way will start this project in 2 weeks I'll probably start a new thread then.

I'm excited to have some pictures to post when I do.

Just called the shipyard haul it out 2nd or 3rd week in January answer's are coming for me included =)
 
In my case removing the engine above the other to set the tank was my way. Had cutup old tank and removed. Put in aluminium tanks , fast forward 8 years and had a bad weld start leaking,so did it again with a boom lift at the yard. Came thru window and lifted engine,trans up and over while crew removed tank thru other side window to ground so welder could do repairs. Then same to put back in. A pain in the ass but can afford the boat/ repair but not the crazy prices that I got for someone else to do it. $30,000.00!!!!!!!

I'm paying £30000 to have our tanks replaced on a Trader47. Engines out through the salon windows. Floor cut out. New tanks, exhausts, engines blasted and painted, everything behind the engines and tanks replaced as it's a once in a lifetime job
 
I'm paying £30000 to have our tanks replaced on a Trader47. Engines out through the salon windows. Floor cut out. New tanks, exhausts, engines blasted and painted, everything behind the engines and tanks replaced as it's a once in a lifetime job

I almost wish i could afford to just let someone do it for me, i dont even feel like its the cheap way out. its going to take effort. hopefully ill have good sucess and be able to share what ive done here. we have gotten so much done up until this point. Haul out we are going to address tanks, bottom, and clean the bildge its kinda nasty. then coat the bildge area's where it can be accessed easily.

Im shooting for a 10 day haul out of sorts. they charge 1 per foot per day on the land part of our marina. i was going to do a 4 day bottom job turn around but these tanks have me bothered after all the reading. the decks do leak some and thats a project for another time we are going to glass over the wood. i figure someone here has attacked that problem at some point.

All in all im excited to get down to it. now just waiting for the correct timing

= )
 
Hey Dave

awsome write up and illustration, definatly given me something to think about before this haul out.

I employee fibergass hands so it may be the way to go.

going to thin about this abit.

= )
 
Lots of great advice, as always, on the forum. I've replaced aged mild steel diesel tanks that were locked in by the engine. Got in there with a sawzall, cut them out and used the pieces for templates for a stainless steel fabricator to make two slightly smaller tanks. Lot of personal labor but solved the problem for a fraction of the cost of yanking the engine. However, on my current boat (46 year old steel tanks) I had local fuel polishing company add second inspection ports and internally clean the tanks. This was after I purchased the boat a few years ago and we had no issues with the tanks, just wanted to know what condition they were in. This company advised me that they do internal repairs using epoxy (clean the tank and epoxy coat inside) and have done many tanks this way. I'd suggest further investigation of what the tanks are like internally before throwing thousands of dollars at a perceived potential problem.
Good luck on your fix.
 
I'm paying £30000 to have our tanks replaced on a Trader47. Engines out through the salon windows. Floor cut out. New tanks, exhausts, engines blasted and painted, everything behind the engines and tanks replaced as it's a once in a lifetime job

Is that price for the entire job or just the tanks?
 
I replaced my own tanks on my twin engine sun deck. The steel tanks were removed using a sawzaw. Made 6 fiberglass tanks(3 per side) totaling the gallon capacity. 3 tanks per side were interconnected using 1.5" fuel hose. Had to remove the exhaust pipe to have room to slide the new tanks behind the motors then forward into place. Probably cost to 4 gs for both sides
 
I replaced my own tanks on my twin engine sun deck. The steel tanks were removed using a sawzaw. Made 6 fiberglass tanks(3 per side) totaling the gallon capacity. 3 tanks per side were interconnected using 1.5" fuel hose. Had to remove the exhaust pipe to have room to slide the new tanks behind the motors then forward into place. Probably cost to 4 gs for both sides

I had a 265 gallon centerline tank removed due to leakage. It was replace with four connected tanks and now holds 250 gallons. It can be challenging to fill them with the fuel needing to flow forward and the air aft. I did find that a Clean-Way Fuel fill really helped dramatically. I highly recommend it. Without it, it took at least 30 - 45 minutes to fill. With it, maybe 10-15 minutes. I can't even tell you why but I had planned to put in more tank vents but now I don't think I need to. I paid for the tanks to be replaced out and in and including fabrication the price was $7,000 US in 2019.
 
Back
Top Bottom