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Shanendoah Forbes

Fuel leak signature 270

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Hi all,

 

Looking for some advice from someone who may have encountered the same problem.  My fuel tank is leaking, likely from the bottom, it is a 20 year old aluminum tank. The main problem is how to access the fuel tank without removing the engine and ripping everything out...I have a 1997 signature 270 in excellent condition with a 7.4L mercruiser with a 70+ gallon tank I believe.

There is small amounts of fuel leaking into bilge and it doesn't seem to be coming from the top of the tank, or the engine itself. I saw some posts and wanted to find out how one would access the old fuel tank? It looks like you could cut a hole and go through the floor of the aft sleeping quarters? There is no easy way to get at the old tank unless you rip the boat apart.

I am also curious if anyone thinks the manufacturer has a suggested solution. Do you think chaparral would know what to do about this? I would guess it's pretty common because it's such an obvious flaw. I don't want to get rid of my beautiful cruiser because of such a simple problem but I am stuck.

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Sorry to hear about your problem ... it's not a simple problem the way your boat and many other express cruisers are build. Yes, you will have to rip a part of the boat and rebuild it later as the fuel tank is practically encapsulated in the hull structure. Removing the engine might be necessary or at least will help in minimizing boat demolition. In addition to contacting Chap for demolition know-how, try to find a service marina or a boat yard that does the complete boat refits and ask them for their advice.

There are other options to research, like sealing the tank from inside or fitting it with a bladder. Apparently either could be done with a much smaller damage to the boat ... but is it a feasible and lasting solution?

Meantime, as you are probably well aware, your boat is not safe to operate even if the leak is small.

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Thank you very much for the response. Our local mechanic said the boat design made it very difficult to change out the tank. He was not very optimistic...my second thought was to cut open the floor, cut the top of the tank and try the bladder system or a smaller plastic tank that would fit inside the original tank. Is that even possible??

I have seen the bladder system suggested on this forum but I am hoping that isn't my only chance of saving the boat. What a bummer.

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4 hours ago, Phillbo said:

Why not post your walk through here so others can learn from your experience?

+1

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+1 for posting the how-to. Have a buddy with a Sig 270 and a leaking tank and he's very depressed.  If it's not too bad, maybe there's hope for him.

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Ok. Weather here over weekend is supposed to be bad. Will try to put something together with some of the pics so you can see what I did. 

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5 minutes ago, Gregoryszabo said:

Ok. Weather here over weekend is supposed to be bad. Will try to put something together with some of the pics so you can see what I did. 

I agree with putting it in the public forum, but I get why that was not your first option...it is probably easier to talk someone through it over the phone and make sure he has your phone number for questions during the project.  So no ill feelings here.  

So I want to commend you for your plans to detail the process in the public forum.  This forum is a fantastic resource for today as well as for those who search the forum later with same or similar issues.  I truly believe the archiving that this forum provides it some of the better purposes for its existence.  

Kudos to you!

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Needless to say, but a fuel leak, and how it is mitigated and repaired, is a major safety issue. 

Be careful.

brick

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1 hour ago, brick said:

Needless to say, but a fuel leak, and how it is mitigated and repaired, is a major safety issue. 

Be careful.

brick

+1

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Agree. I hired someone to drain the tank and clean it out before I started my work. Too risky with gas and gas fumes. And I replaced the tank with a new one. 

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I purge all of a    WHOLE   fuel tank by connecting the hose of a shop vacuum cleaner to the     EXHAUST  fitting of the vacuum cleaner. That   BLOWS fresh air INTO THE TANK fitting.  I leave it running until there is    0 trace of gasoline.   I leave it running when I cut into the tank metal.   Safest way I have found if cutting or grinding is required.

You may have some gas fumes also from the space under the tank to blow out also if grinders or flames are used.

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19 minutes ago, cyclops2 said:

I purge all of a    WHOLE   fuel tank by connecting the hose of a shop vacuum cleaner to the     EXHAUST  fitting of the vacuum cleaner. That   BLOWS fresh air INTO THE TANK fitting.  I leave it running until there is    0 trace of gasoline.   I leave it running when I cut into the tank metal.   Safest way I have found if cutting or grinding is required.

You may have some gas fumes also from the space under the tank to blow out also if grinders or flames are used.

Boom!

brick

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1 hour ago, cyclops2 said:

I purge all of a    WHOLE   fuel tank by connecting the hose of a shop vacuum cleaner to the     EXHAUST  fitting of the vacuum cleaner. That   BLOWS fresh air INTO THE TANK fitting.  I leave it running until there is    0 trace of gasoline.   I leave it running when I cut into the tank metal.   Safest way I have found if cutting or grinding is required.

You may have some gas fumes also from the space under the tank to blow out also if grinders or flames are used.

WHAT THE HECK? Did you never hear of static electricity.    You have posted some doosies but this is by far the absolute worse. Brick is so right. BOOM...

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Quote

 

You both are right. I do have a set of grounding  clamps in use while the shop vacuum is attached to a metal tank.   Thank you for pointing out a safety omission.

The only tank I refuse to purge is a plastic / fiberglass one. Static electricity in none metals, is not a well defined science

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24 minutes ago, Wingnut said:

WHAT THE HECK? Did you never hear of static electricity.    You have posted some doosies but this is by far the absolute worse. Brick is so right. BOOM...

 

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Another safer way is to purge with the exhaust fumes from a car / lawn mower exhaust pipe. The CO & CO2 levels are much safer than the air cleaner method.

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In the natural gas business we would do cutting and welding work under a tent. We would tent the work space and allow the area to completely fill with natural gas before cutting or welding.  No oxygen no BOOM. Just pure natural gas.

Never felt comfortable doing hot work. 

Joe

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Our raw gasoline , crude, and naphtha tanks are well ventilated before entry and cleaning. The COPUS brand blowers are air driven, cast aluminum units with metal blades and non-lubricated air bearings so that continuity is constantly maintained. Bonding is initially established and constantly monitored as are LEV levels and O2 content. When the levels are above the UEL (Upper explosive limit) the tank is safe for entry as vapors are too heavy to ignite. Entrants are placed in protective suits and fresh breathing air is supplies. When levels are below and remain below the LEL (lower explosive limit) entrants can enter with organic vapor respirators only. The tricky part is staying well clear between those two numbers. We too do work in an inert environment, but use nitrogen as it is non-combustible, yet still lethal.  W

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I was a junior electrical designer at the then Davis Emergency Equipment Company. I spent many days mixing up upper & lower levels of explosive gases to test the first Westinghouse Integrated Circuit I used,  to give accurate readouts of gas line  leaks.  Platinum  sensing elements & Natural gas.  Good old design days.   :)

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