Bad Fuel Tanks

I have read a lot about costs to replace both tanks lets say on a Marine Trader 38. Now the tank top is bad due to deck leaking probably around the fill hole. I read 10,000 dollars to replace both tanks Engine haul etc,etc. Is is crazy, stupid and worse to cut the deck out since the core is no good and pull tanks, thus leave engines alone. Repair the decks. Seems like it would be easier and maybe done by someone handy. Archie Bricker/Remedy

My tanks would not fit through the deck and the deck is not directly above the fuel tanks. When you replace the core in the deck, I would leave at least the bottom layer of glass to support the new core. My two cents says to remove the engine then replace the tanks. I did it for $4k my labor. See my blog for pics.

A large part of the costs are labor. Once you have determined how much work you are willing and able to do, then the costs fall into place.

Several good tips and threads in the archives on TF on how to do the job. Review this information, talk with tank shops, determine your metal preference, talk with experienced yards etc to further pin schedule, activities and costs down.

Don't forget to fix those deck and window leaks. Pulling the engine(s) allows you to do ER cleanup and repainting. Get the old girl fixed up right!

MAN, YOU ARE NOT AFRAID TO GET YOUR HANDS DIRTY. Advice taken. Thanks Archie/ Remedy

I am closing on a 36 marine trader today. (1986) There is no visual sign of a problem yet. I did get an estimate to replace both around 10 grand. Holes would be cut in the sides for the new tanks. I have started a separate account for "boat problems" and when a problem arises will have the money for repairs as I cannot do that job myself. Just something to think about.

Greetings,
Ms. D. "Holes would be cut in the sides for the new tanks." You may want to re-think that approach. I think there was a thread dealing with disturbing the structural integrity of a boat in such a fashion. As usual, two camps. One said "Don't do it" and the other "No problem". I'm on the "Don't do it" side.

gelcoat will almost never match up over time if the hull sides are repaired. Painting is the solution but while beautiful it is costly.

Holes are cut into the side of the boat all the time to replace tanks and engines. If done right there is no issues. There are many pics from boat yards even doing this to 100'+ yachts. It's the only way for some. There is also a video of it being done to the bottom of the hull on a grand banks.

One place drops Grand Banks through the bottom...easier than repairing the sides to match they say.

Either you trust major fiberglass repair or not..

My solution was cut the old ones out and replace with smaller plastic tanks....a one handed Sawzall from Rigid made it tolerable.

Unless you plan on voyages beyond the Atlantic East coast or theBahamas/Cuba....my 300 mile range on 2 - 56 gallon tanks gets me from cheap fuel to cheap fuel..... back and forth from NJ to FL year after year.

Even if it's not enough range to always get cheap fuel...my replacemental tanks cost a total of $500 and what is cool...I can see into the tanks so I can top off to the very top and drain down to the very bottom...so all but a few gallons are usable. An always fresh fuel with no water or sludge build up...if there was...add some solvent, release the restraint, slosh around and siphon out in an hour or two

There are all kinds of options these days to replace failed tanks with many price points and levels of hands on involvement. Don't break out the SawsAlls just yet.

How about some solid ideas on how to avoid premature fuel tank failure?

As it turned out, my tanks were solid as a rock...just rusty as heck on the outside...which leaves one in doubt no matter what the repair if some experts claim many rust from the inside out.

Plus they had a layer of crud in them that was only coming out with a scrubbing...no amount of motion and polishing was getting this out.

Plus I more than doubled the amount of storage space in my engine room. Utilizing space on a liveaboard that was being wasted by storing old fuel didn't make sense to me.

All in all...I would do it again for the reasons stated even if I had a guarantee the tanks would have lasted another decade. With no gurantees, cruising away from home 4-6 months of the year, replacement on my terms seemed a no brainer.

But as in all things boating...if I couldn't do it myself, I couldn't afford large boating at all.

Plus, not too many options I think that are all the easy, practical, cost effective, really effective, and have as many plusses in other columns that I like.

Cutting holes in the topsides to take the tanks out makes no sense. You'll spend more time patching, fairing, gelcoating or painting the topsides than you would on the rest of the project combined. Cutting holes in the bottom makes less sense. Never actually looked at it but I'd be surprised if you could get the tanks out through holes in the deck. Besides that rebuilding the decks after would be a project. Pull the engine, cut the old tanks up if you have to to get them out. Then size new tanks that you can fit in.
While headed down the slippery slope of repairing TT's while the engine is out look at you engine stringers. Seen a lot of rotten ones.

As RT stated ' don't do it " There are yards around that could replace the tanks with smaller ones only losing a little in capacity. Yes they do it on big yachts because there is no other way. Cut a hole in the side of my boat - no way !

I just went through this exercise. Look for the topic I started. I looked at all options. What made most sense for ME and MY BOAT was to cut up the old, leaky tanks and replace with smaller tanks that could fit in without removing engines.

I personally wouldn't mess with removing whole tanks through the hull. Too difficult to find a glass dude that knows what he or she is doing. They all say they're the best in town. Not true. And should you find a true expert, they're expensive!

I replaced two 300-gallon steel tanks with six aluminum tanks (three on each side) totaling about 550 gallons. My final cost was about $19,000.

Good luck!

Replacing two same tanks with two same tanks has cost two people I know about $20K without cutting the hull or bottom. No work done by owner.

You realize that we have yet to prove the tanks are in fact actually leaking....

It's more fun to spend other people's money on tank replacements than on correct diagnosis.

Glad I am enjoying my extra storage and $19,400 in beer money for doing it my way.

And I was still enjoying the $28,000 in beer money saved on my own peel, fix and reglass/barrier coat my bottom.

Then there is there is the.....getting fed up with working on boats!!!!!!

A couple of places in my area of WA state offer epoxy repairs for tanks as well at a fraction of the cost of replacement. It no doubt requires a tank that is not totally rusted out I should think. The tanks in my boat were cleaned and declared good to go when I bought it and so far so good, but I did have that leaky stand pipe fitting on one tank, but that's fixed.

Arthur Bricker said:

I have read a lot about costs to replace both tanks lets say on a Marine Trader 38. Now the tank top is bad due to deck leaking probably around the fill hole. I read 10,000 dollars to replace both tanks Engine haul etc,etc.

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If the defect is confined to the tank top and or filler tube, confine the fix to that. Cure the rust, seal the top, fix the filler tube. Yes, the entire tank may eventually need replacement, but the cost to fix what presents now is modest and the alternative scary. Who knows how long fixing all that is wrong and leaving be what is not an issue, may last. Quite a while in my experience.

Custom made bladders installed in each tank are not that expensive and do not require the boat to be ripped apart.

A bonus is they are removable so they can be cleaned if bugs get in the fuel.

We sold our MT 34 Aft Cabin Whistful back in 2000, I think.
The couple that bought it ran it for a few years and had tank failure. Not sure if one or two, doesn't matter though. They replaced them with plastic, not sure of the cost.
We had the boat for 8yrs, our survey didn't pick anything up, and neither did theirs, but we did have teak decks, and we all know how that goes.

I would definitely do the plastic tank route myself. I have 3 saws-alls (and not afraid to use 'em), 2 are battery powered And our boat carried way more fuel than we would use in 2 original tanks.

My last boat had black iron tanks. One leaked so I cut them out and replaced with them multiple smaller tanks as others have suggested.
Current boat the 100 gallon aluminum tank started leaking one month after purchase. It was a 35 year old tank that came out through the ER hatch after moving the engine out of the way into the salon.
If you buy an old boat, be prepared to get dirty, sweat and bleed or have a good reserve for repairs. For me it's a little of both.

"I would definitely do the plastic tank route myself."

Plastic is probably the best but the install is a PIA.

You need to place the tank, fill it with fuel, let it grow a bit , then lock it in place.

FF said:

Custom made bladders installed in each tank are not that expensive and do not require the boat to be ripped apart.

A bonus is they are removable so they can be cleaned if bugs get in the fuel.

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This is a sensible alternative, leaves you with some beer money too!
Take care to provide a safe environment for the soft tank, and it will last forever.

kapnd said:

This is a sensible alternative, leaves you with some beer money too!
Take care to provide a safe environment for the soft tank, and it will last forever.

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Think of resale. Today's dollars are cheaper than tomorrow's dollars.

fastinated said:

Holes are cut into the side of the boat all the time to replace tanks and engines. If done right there is no issues. There are many pics from boat yards even doing this to 100'+ yachts. It's the only way for some. There is also a video of it being done to the bottom of the hull on a grand banks.

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Yes but t ain't going to happen for only $10,000.

Giggitoni said:

Think of resale. Today's dollars are cheaper than tomorrow's dollars.

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I seriously did...I think tank reduction done well is an easy sell when explained correctly...

Like getting rid of teak decks....can be sold as a positive either way...just typical media slant.

kapnd said:

This is a sensible alternative

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No it's not.

At least in the majority of cases.

If it was, it would be done all the time.

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.


so many different boats and combos and needs...hard to say what solution fits each case.