Replacing rusted out fuel tanks

[Bigfish]

No ****... Thanks dad!!

 

[oscar]

Never said 12' square hole... You did... Just exploring all possibilities.. I witnessed a local boatyard cut out the tanks through the hull on a 53' Hatteras and seal it back up where you couldn't even tell.. You obviously don't know what you're talking about... They did it in a few days too.

That's fascinating, especially considering that the tanks in a Hatteras 53 are fiberglass and integral to the hull... Removing them would mean cutting up the boat.

Really starting to wonder now why you are asking repeated questions on this forum that seem to severely obfuscate your vast knowledge.

I'm done. You don't want my help.

 

[BruceK]

There was a frightening video someone posted on TF of someone cutting the hull sides out of,I think, a GB36. Not for the fainthearted. Putting it back together, strength restored,would have been challenging.
I hope you get a view of the top panel and filler tube,a good starting point in view of how/when the leak first showed up.

 

[Bigfish]

Might not have been a Hatteras.. In fact now that you mention it, it was NEXT to the 53 Hatteras and I think it was a 47 Jefferson... You know that boat intimately too? I'm done with your help too... Thanks for nothing...

 

[mvweebles]

Emotion aside, will be very interested in what you find when you get a scope down. Will also be interested in how many inspection holes are needed to get around blocking and such. As mentioned previously, I never did find my leak even after pulling the tanks out. I hope you have better luck with your scope and it is just a loose hose clamp on the filler neck, though dumping 50-100 gallons seems much more severe than that.

This thread is labeled "Replacing rusted tanks" with OP asking about feasibility of taking them out sideways through hull - a 350g tank would take a pretty big hole. While it makes sense to consider all options, myself and many others would be stunned if you found a qualified marine professional who advises its the best way to go unless there was simply no other option.

I know you're really frustrated right now, and I can imagine some of the comments are not what you'd hoped for. But please post updates - I'm interested to know how this ends.

 

[syjos]

Really starting to wonder now why you are asking repeated questions on this forum that seem to severely obfuscate your vast knowledge.

I'm done. You don't want my help.

Engaging in Trawler Forum is a personal choice.

No one is compelled to open or read a thread or post.

If something irritates you, don't open the thread.

If insults, name calling and other unpleasantries are you thing, you should consider Facebook.

 

[Bill R.]

I had a similar problem on my 36' twin engine and after looking at cutting the teak and holly sole and removing the aft doors and tight clearance everywhere I decided to cut a hole in the side.

3' by 7' hole for a 175 gallon tank. The guy used a 1/8 wide blade to cut the hole and while the tank was out he placed a large flange in the inside for the hull section to bond to when re-installed

None of the dock wardens can see where the hole was. However, you must be assured the glass guy is very experienced.

I believe my boat is a little over built so that helps.

Worked for me,
Bill

 

[syjos]

If the rust or holes are not too severe, there are companies that cut access holes in the tank, clean the tank and coat the interior with some sort of coating with success.

I've also witnessed a tank welded from the inside while still in a fishboat.

Here is a TF post from someone that had it done:

https://www.trawlerforum.com/forums/s6/diesel-fuel-tank-repair-internal-coating-3719.html

 

[FF]

"While it makes sense to consider all options, myself and many others would be stunned if you found a qualified marine professional who advises its the best way to go unless there was simply no other option."


Chopping a hole in the side is an excellent choice for a steel boat.


The welding can restore 100% of the boats hull.

Sadly most GRP boats wiggle and flex too much for this method.


The GRP hull should be uniform so no hard spots exist where hull flexing would start cracking off of the repaired section.

Yes, military and pilot boats are usually 400% overbuilt and don't flex much , so maybe , but most yachts could not handle the repair and function well.

 

[Sailor of Fortune]

Once you put the new tanks in there is no good access behind them to put the side back together. Fiberglass needs a wide fairing to adhere properly. Steel boats are just welded from the outside.



Cut up the steel tank from inside the engine room using a saws-all. Replace with pre-made plastic tanks that fit the existing space and will fit around the engines. Connect them all together for less but more appropriate tank volume.

Best advice ! Unless you need long range fuel ability. Coastal cruiser? this is the easiest,least expensive way

 

[Benthic2]

I would think with a tank that big you could cut a hole in the deck to get a person into the tank. Cut it up and pass the pieces out hole. Have a new tank built in place by passing the pieces into the hole and welded in place. That's going to involve a lot of labor, materials and a welder who is willing to try it.

another option: Don't use that tank, or only fill it half full. Is the other tank the same size ??

 

[oscar]

cut a hole in the deck to get a person into the tank. Cut it up and pass the pieces out hole

Wonder what OSHA would have to say about that. IF you can find someone to do be down there grinding away for 10 hours. Maybe in Sri Lanka on the ship scrapping shores but not here.

 

[RonR]

Wonder what OSHA would have to say about that. IF you can find someone to do be down there grinding away for 10 hours. Maybe in Sri Lanka on the ship scrapping shores but not here.

Its doable with the right equipment, we do it all the time in the refinery's.
I've been flowing the treads and my $$ is on a failed connection at the deck to tank top, or a rusted out fill neck to the tank top if it once had teak decks.
But I'm no pro.

 

[oscar]

Its doable with the right equipment, we do it all the time in the refinery's.

Yeah, but that's not a tank the size of two oil drums, and you have $$$ of safety equipment and top of the line cutting equipment. Different ballgame.

As far as the hose, yeah. Either that or the top is rotted through. That's where they go first.

 

[mvweebles]

Does a rusted out top or filler neck explain 50-100 gallons of diesel spill?

 

[SteveK]

Does a rusted out top or filler neck explain 50-100 gallons of diesel spill?

50-100 gal may be a lot more than actual. Diesel spreads quickly.

When spilled on water, diesel oil spreads very quickly to a thin film. Even when the oil is described as a heavy sheen, it is 0.0004 inches thick and contains about 1,000 gallons per square nautical mile of continuous coverage. The volume of oil in areas covered by streamers would be much less. Silver sheen only contains about 75 gallons per square nautical mile.

 

[mvweebles]

Could also be less than actual. I take the OP at his word. In another post, he mentioned he spent about $4k on cleanup. But I may not remember correctly.

Bottom line. There is missing information. I too will be interested in the OPs findings if he reports back.

 

[PM]

I really feel bigfish's pain. But seriously isn't it time he formulates a plan and gets into his bilge or find someone else who can?

He has had at least four threads on the tank issue and I think two on the engine issue.

I understand that money is an issue and that arthritis is also an issue.

When I was younger I could accomplish three or four major boating tasks in a day. Things like pulling and replacing batteries, ripping up teak, waxing a boat side, three or four coats of bottom paint. Twenty or thirty trips into the bilge didn't bother me. Things like that.

Now that I am older and more feeble, maybe a little wiser I don't even consider doing big projects in a hurry.

Pulling an engine to get at and remove a fuel tank is certainly a daunting task when a person considers it. But is it such a big task to set a goal for the day of say, disconnecting the transmission from the engine, or totally freeing up one engine mount, or disconnecting the fuel supply?

Break it down into smaller workable, doable tasks that creaky old knees can do in a couple hours then rest up and plan the next step, preferably for the next day. If he had actually started the project when he found the problem a number of weeks ago, he would probably have an engine out by now.

pete

 

[BruceK]

Different people work at different speeds in different ways that may annoy others. It is taking time, but were we in the OP`s shoes(assuming whoever took Howard`s shoes haven`t taken them too) we might see it differently. I hope he gets a look at the top panel and filler tubes, as a starting point for where the leak(?s) is/are or not.

 

[Lou_tribal]

Different people work at different speeds in different ways that may annoy others. It is taking time, but were we in the OP`s shoes(assuming whoever took Howard`s shoes haven`t taken them too) we might see it differently. I hope he gets a look at the top panel and filler tubes, as a starting point for where the leak(?s) is/are or not.

What I find odd is to start planning tank removal, hull cut and all these daunting tasks without just knowing where the leak is.
Maybe the leak is just and only a disconnected deck fill hose and nothing that requires heavy work.
This remind me the guy who take apart his computer that is not working when it was just not plugged in...

I don't mean anything bad when writing this, but before planning a repair, better know the cause.

L

 

[Tabascojunkie]

Wonder what OSHA would have to say about that. IF you can find someone to do be down there grinding away for 10 hours. Maybe in Sri Lanka on the ship scrapping shores but not here.

Done all day every day in construction of steel hull vessels. You should see some of the holes I’ve seen welders work twelve hour shifts. Lots of ventilation.

 

[mvweebles]

Question: how many folks who have had leaking tanks actually found the leak? I had a small weep on my 200g tank that must have been at least midway down the tank. Tank was over 8-feet long and I never did find the weep. I couldn't even isolate what end the weep was on due to how the blocking was constructed (weeped diesel came out limber holes along the stringer-like blocking). If I had tried harder, perhaps I would find it.

From experience, finding liquid leaks can be super frustrating. Even cut-up, I'm not sure where the leak was, though I didn't spend much time searching at that point. Sounds like the OP's situation is quite a bit worse than my weep, but still - his tank is almost 2x the size of mine. I would think it very difficult to actually find the leak unless it was a pretty big gash. Maybe shine a super bright flashlight down the filler neck and see if there are any visible points of light in the engine room?

 

[JLD]

What I find odd is to start planning tank removal, hull cut and all these daunting tasks without just knowing where the leak is.
Maybe the leak is just and only a disconnected deck fill hose and nothing that requires heavy work.
This remind me the guy who take apart his computer that is not working when it was just not plugged in...

I don't mean anything bad when writing this, but before planning a repair, better know the cause.

L

I, too, do not understand the thinking of the OP.

I would never attempt to fix a problem, without first knowing what the problem is. If it can be determined that the tank is actually leaking, there seems to be little choice but replace the tank. If the problem is something simple, then it can be more easily fixed.

If it turns out be a simple fix, I think the OP also needs to think about the longer term. The odds are that 40+ year old tanks will eventually fail and need replaced.

I know the OP will NOT like this suggestion, but it seems to me that if the tank is bad the only real choice is to remove it or get rid of the boat.

 

[Solly]

If you want to find a leak in a tank you can fill it with water and pressurize it with air. Only needs a couple lbs. pressure. I think they test new tanks with like 3-5 lb. of pressure ????
Not sure on that..

Of course it needs to be out, sealed up, and some way to hook up an air hose.
If it's leaking probably not worth the trouble.

 

[Sailor of Fortune]

If you want to find a leak in a tank you can fill it with water and pressurize it with air. Only needs a couple lbs. pressure. I think they test new tanks with like 3-5 lb. of pressure ????
Not sure on that..

Of course it needs to be out, sealed up, and some way to hook up an air hose.
If it's leaking probably not worth the trouble.

I think they only put 1 pound or so to tanks...

 

[Comodave]

My tanks have a certification that says either 3 or 4 pounds, offhand I cannot remember which without looking.

 

[SoWhat]

OP has resisted just about all suggestions for solutions. I suspect he is still looking for a quick cheap fix. No such thing. Either pay the yard or buy a lot of tylenol.

 

[mvweebles]

My tanks have a certification that says either 3 or 4 pounds, offhand I cannot remember which without looking.

My recently replaced tanks were tested at 3 lbs for a day.

 

[SteveK]

If you want to find a leak in a tank you can fill it with water and pressurize it with air. ..............

I was about to say the same, us know it all's. Add a dye to water. with or without pressure a trail to follow.





Then

A few gallons of this (he says tongue in cheek)

 

[mvweebles]

How do you evacuate the water from the diesel tank? I guess I'm still skeptical as I'm guessing less than 1/3rd of the tank will be visible so seepage will be a problem. Meaning where the leak appears probably could be deceptive.