# cape horn fuel leak??



## Rastaman (Oct 5, 2007)

I have had a pretty major fuel leak in the 31 cape and was wondering if anyone else has experienced the problem. I have not posted the issue because I saw no need to give them bad press but we have been dealing with the problem fora while now. The first time I called the factory and they were real nice. Told me to bring it in and they would replace the fuel sending units. I pulled the boat and drug it to milton. They did something and told me it was ready. I towed it back and put it back on the lift.

I know there may be an odor due to the poly tanks but this is fuel floating in the bilge. I can see it in the water when I pump over. It kind of makes me feel like I am driving around on a ticking bomb . Anyone else had this problem and, of so, was it fixed?


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## X-Shark (Oct 3, 2007)

> It kind of makes me feel like I am driving around on a ticking bomb .




DA! You are.



There are several threads on Classic Mako.com right now about plastic tank failures.



http://www.classicmako.com/forum/topic.asp?TOPIC_ID=18485&SearchTerms=Plastic,fuel,tank,problems



http://www.classicmako.com/forum/topic.asp?TOPIC_ID=19102


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## brnbser (Oct 1, 2007)

been fishing on SET 4 Life's '07 31' since Dec of last year and fishing it hard on the tournament circuit. no issues with fuel. And when I say fishing is hard, I mean as much as 6-8's in a tourney in March and 4-5's in a tourney 2 weeks ago. the boat has been flawless other than the normal livewell pumps because we've always got bait in them and they even modified that design with better quality vendor parts.

give the guys as Cape Horn a chance, I'm confident they will make it right. they are by far the best I've even seen or heard of at willing to take care of their customers. I know it's a pain to take the boat back to Milton, but to me it's worth knowing the factory is taking steps to make it right and not some dealer who really doesn't know "everything" about the boat.


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## David Ridenour (Sep 28, 2007)

The fluid remaining might be old and from the original leak. I'd put it on a trailer and flush the hull/bilge out for several hours with fresh water. You might find a fuel neutralizer and add it in and put the plug in and drive it around a little to aggitate it in the bilge.Chances are the foam has absorbed some fuel and it will take a lot of time and dilution to remove the odor and residual fuel.If that dosen't seem to correct the problem I'd take it back and see if they will make it right.


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## sosmarine (Sep 28, 2007)

I agree with David. There are several bilge cleaner available at West Marine. Or mix up some Liquid Dawn and water and dup it in the tank compartment. After rinsing with plenty of fresh water, hook the hose up to the exhaust side ofa shop vac, if you have one, and pump air into the compartment for a few hours. This is what they do with aircraft to evacuate fumes. Not a shop vac, but you get the idea. Also make sure the bilge area get cleaned and dried as well. After this don't fill the tank to the top and check for leak. If it doesn't leak then fill up.


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## user207 (Oct 1, 2007)

_I have known the people over at Cape Horn for a very long time. I am sure that if there is a problem with the tank leaking, they will take care of it._


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## X-Shark (Oct 3, 2007)

> dump it in the tank compartment.




They are talking about the tank coffin, not inside the tank.





> Put around 30 psi in the tank and hook it up.Come back and check every hr.If you are losing 5 lbs an hr or more you have issues.




30PSI? That would be catastrophic. The tank would have a new zipper in it.



Note the exerted pressures on the tank in my boat with ONLY 1 1/2PSI put in it. 

this is a modeled drawing done by my brother Rick. He has a Masters in Mechanical Engineering and is a PE.


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## tiderider (Oct 1, 2007)

X-Shark is dead on, if you put 30 psi to the tank you will have a leak. While I was in the Coast Guard we tested those 6 and 8 foot steel bouys at around 2 psi, and it took some very careful equipment to make sure it didn't get above 2.5 psi.


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## sosmarine (Sep 28, 2007)

X Shark, thanks for clarifing my statement to www. I would be lost person to say put water in fuel tank. The reason for the water and Dawn in the tank compartment is to illiminate the smell. 

I also agree about NOT pressurizing a tank to 30 psi. 5 psi is plenty to check for a leak.


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## Tuna Man (Oct 2, 2007)

:banghead:banghead:banghead What kind of pressure builds up in a unvented plastic auto fuel tank on a hot summer day????? Hell of a lot more than 2psi


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## tiderider (Oct 1, 2007)

Here's the CG requirement. It's has a bit of technical jargon but basically says go slow, use water and pressure not to exceed 3 psi.

http://law.justia.com/us/cfr/title33/33-2.0.1.8.44.10.226.34.html

Some of you folks are just plain scary with your advice.


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## ohana (Oct 18, 2007)

it might be an oversight, but a couple of months ago I had the same problem. After checking all of the hoses, I noticed that the hose connection to the top of the fuel vent had fallen off. Every time I tried to top the tank off, it would run out of the vent hose and down into the bilge.I have a 200 gal tank. Might be worth checking.


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## tiderider (Oct 1, 2007)

Go for it hoss. I seriously doubt that you could hold more than 5 psi on a completely sealed fuel tank, but sounds like you have it all figured out.


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## tiderider (Oct 1, 2007)

Hey man yeah it's 3 psi on a gage that means plus the 14.7 atmospheric pressure, but since everyone I know basically reads pressure on a gage then it's 3psi. I'd explain it to you but I don't think you want to hear it so, let's just agree to disagree.


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## tiderider (Oct 1, 2007)

The problem with your argument is weight verses pressure. All the items you compared the fuel tank too, i.e. a tire, a pressure tank are designed to hold PRESSURE, a fuel tank is designed to hold volume and weight......and it's vented so as not to hold pressure. That's it, I'm done arguing about basics.


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## tiderider (Oct 1, 2007)

You're kidding me, Right?


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## tiderider (Oct 1, 2007)

> Im pretty sure you have never taken out a fuel tank or even done this.
> Flush a fuel cavity that is enclosed in foam wich most cavitys are sealed anyway so the fuel leaks up the side walls and over into the bilge areas.


You would be wrong. I was an engineer in the Coast Guard for 24 years. I've pressure tested fuel tanks up to 30,000 gals. I'veQA'd even more. Both Ingalls shipyard and the Coast Guard yard in Baltimore follow the same procedures that I previously referenced. They adhere because it's not my theory but basic mechanical engineering. I've also pulled out many a rotten fuel tank from small boats. More than half my life has been spent taking care of stinking boats. 

You can hook up all the pressure you want to a fuel tank, if it's leaking it really doesn't matter, but if it is tight and you can put enough air into it to reach over 3 psig then there's a possiblity that it will rupture.


Here's another example. In this case a Convault fuel tank is being pressure tested. It's primary wall is steel and the outer casing is concrete.

http://www.convault.com/pdfdoc/TestingMan.pdf

Here's the one point you and your uncle probably won't agree with:*<P align=left>CAUTION: The test air supply should not be more than 3 psig. Use only<P align=left>calibrated diaphragm type air pressure gauges with a zero to 10-psig dial span.<P align=left>Set pressure relief valve in test air supply line at 3 psig. Over pressurization of a<P align=left>tank may burst the tank and cause injury.<P align=left>*


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## tiderider (Oct 1, 2007)

I want to appoligize to Rastaman for sidelining this thread. I'd just hate to see someone destroy their boat or even worst getting hurt. Again Sorry.If you want I'll delete my posts and look the other way.


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## Boggy Basin Boy (Sep 27, 2007)

Took you all of three days will.:sick what is your problem man?


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## frydaddy (Oct 1, 2007)

Some of you guys need to slow down on your reading and actually *read what you are reading.No body said to put water in the tank!* I don't have a horn but did have a problem 2 years ago when I replaced the aluminium tank in mine. One morning I was heading out and the fumes were so strong I smelled it when I walked out the door of the house. All kind of gas in the bilge. Needless to say I didn't take it out that day. Ended up being the sending unit for the gauge. The rubber gasket had squeezed out due to my overtightening it when I installed the unit and gas had bubbled out during the heat of the day. Didn't dare turn on the bilge for fear of lighting up those fumes. Took dishwashing liquid, mixed up a five gallon bucket or five and soaked the coffin (area the tank sits in with the foam) and flushed for several hours. The next dayIfilled er up with more water and had no sign of fuel floating around. The smell was still there, just a little bit, but no signs of fuel. Didn't tell the wife about the situation and got her her up in the boat to turn on the bilge for me, you know just in case there was some fuel down there, ha ha.:blownaway I was still leery for the next 2-3 trips because of the smell still being there. It is long gone and have not had any more leaks to date.

When these boats sit out in this wonderful Florida sun they do build up some pressure on those gaskets on the sending units and any loose hoses you might have. These are items you need to check periodically to keep from having an explosive situation below deck. I check mine twice a year, spring and in the heat of summer, late July. Never had a leak before or since but it's worth the spending the time checking itfor the peace of mind and eliminating a hazard that could cause you to lose more than a day on the water.

The rule of thumb is if you smell gas, you got a problem. *Find out what it is before you* turn on anything electrical, especially below deck. One mistake and *BOOM!!!:blownaway:reallycrying*


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## DreamWeaver21 (Oct 3, 2007)

A can of coke at room temp is about 40 psi...I would hope a fuel tank would be built as strong as a coke can.


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## sealark (Sep 27, 2007)

Will, I hate to tell you but one foot of salt water exerts a pressure of .445 PSi. So a fuel tank 2 foot high would only have approx. .890 PSI or less than 1 (one) PSI exerted on the tank. Gas would be slightly less because it weighs less per gallon than salt water. So 30 psi on a rectangular tank would be way too much pressure to test it at. 2 psi max would be at the max.

Frydaddy, pressure doesnt build up in a boat fuel tank in the heat because all boat tanks have vents to the atmosphere. What happens is with a full fuel tank the heating causes the gas to expand and that expansion causes the fuel to rise higher in the vent and fill hose which puts a little more pressure (due to the hight of the fuel)on the bad gaskett of the sending unit causing it to leak.


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## BigFishKB (Oct 1, 2007)

> *www.fishing (10/18/2007)*
> 
> 
> > *tiderider (10/18/2007)*You're clueless. I hope you don't kill somebody one day with your ignorance. Pressure testing tanks is a lot more involved and risky than slapping on stucco.
> ...


Hey, you need to spend more time working on your boat!!!!! No one gives a shit about what you know!!!!!! Leave it alone and quit trying to be a bad ass!!!


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## submariner (Oct 2, 2007)

Not sure the tank would rupture at 3 psi, but do know that my tank (recently replaced by me) has a warning not to pressurize above 2.5 psi. Basically if you pressurize the tank higher, the manufacture will not stand behind it. While it take sensitive equipment to measure 2 or 3 psi, hydros are done at low pressure all the time. A hydro(which a pressure test is) is normally done at 115- 150 % of normal operating pressure. Since the tank is vented, the normal operating pressure would be 0 psig or 14.7 psi

Either way the right answer since the manufacture is local, take to them.:banghead


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## sealark (Sep 27, 2007)

Submariner, The weight of the fuel in the tank will create a pressure on the tank at .445 PSI for every foot of depth of the liquid. So a two foot height tank will have Approx .890 or a little less than 1 PSI exerted on the bottom and will decrease as you go up on the sides of the tank.

:doh


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## bamachem (Oct 2, 2007)

> *www.fishing (10/18/2007)* blah, blah blah. piss and moan, piss and moan. spouting off crap and changing the subject. yada, yada, yada....


anyway, here's some good reading for you on vessel fuel systems. 

http://www.boatus.com/foundation/cleanwater/drops/FuelSystems.asp

"An air vent allows for the movement of air in and out of the tank during the fueling process and regular boat operation. *A vent also accommodates for the expansion of fuel when the temperature warms up or when the boat gets jostled about as a result of normal use. When pressure builds, it must be released ? on boats it is released though the tank?s vent.* Unfortunately as many boaters know, sometimes fuel, as well as air, escapes through the vent."

boat tanks are NOT meant to be pressurized above 3.5 PSIG(that's psi-GAUGE), and that is ONLY for leak testing the tank at the original manufacturer before shipping and installation.

the example you gave of a pressure tank (NOT AIR COMPRESSOR) w/a 30 PSIG fixed pressure is hooked to a fuel tank is very dangerous and is very generalized. if the pressure tank (air source)is 5 gallons and the boat tank is25 gallons and empty with the vent line sealed off, then you will have a total volume of 30 gallons and the pressure will equalize to approximately 5 PSIG - WAY TOO MUCH for a poly tank and VERY DANGEROUS if it's a metallic tank. as the vessel tank size gets smaller, then you have a higher and higher equalized pressure and amore dangerous situation.


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## bajafisherman (Oct 8, 2007)

i haven't had problems with the tank but with the ball that pumps to the filter....but i know the people at horn will take care of it....they have treated us good with everything and other people i know also...


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## X-Shark (Oct 3, 2007)

> i haven't had problems with the tank but with the ball that pumps to the filter..




Always replace the squeeze ball with a OEM unit. The Tempo units that they sell at West marine are known to invoke new problems.



Read my signature. Tempo squeeze balls fit this bill.


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## Rastaman (Oct 5, 2007)

Ummm.....thanks, I think. Sorry to cause a storm. I can assure all that I am not inclined to put any pressure on the tank. It seems to do a fine job of leaking without the added pressure. I will take it back. I just wanted to know if my boat is special or if the fuel leak is a widespread issue.


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## BigFishKB (Oct 1, 2007)

Will, if the shit is getting old then quit starting it!!!!!!!!!!!!!!!!!!!!


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## DreamWeaver21 (Oct 3, 2007)

All the other BS aside. I think it is an isolated incident. Try THT and see if anyone else had that issue.


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## tljbabc (Oct 22, 2007)

man looks like the old forum days :bowdown:bowdown:bowdown:bowdown


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