How Many of Your Still Have the Original Metal Fuel Tank?

[rardiH36]

I am asking because I am getting concerned about mine. I don't see any obvious signs leakage. But of late, my bilge water has a bit of an oily feel to it. I don't see any oil sheen on the outside water surface when I pump the bilge. But the pump doesn't take all out to the bilge surface level. And oil floats. But then when I then sponge the bilge completely dry, the squeezed out water from the sponge over the side does show some oil sheen on the surface. No diesel odor however.

I am thinking that my tank is showing the very first signs of leaking from the bottom and I can't yet see the route the slow drip is taking to the bilge. Not enough to identify for sure yet.

 

[Johnb]

Re: How Many of Your Still Have the Original Metal Fuel Tank

I still have the original tank.

 

[B757Captain]

Re: How Many of Your Still Have the Original Metal Fuel Tank

I repaired mine (1986 Hunter 40) about three years ago. Two holes in the bottom from corrosion due to the factory bed/rails. They were wood rails glassed in, the glass/roving trapped moisture - the tank showed corrosion only in the areas in contact with the rails. I rebuilt the area using starboard strips for the tank bedding. The tank was clean as a whistle inside!

I am in the process currently of building an additional water tank to fill the void in the transom area and just pulled out the water tank. Same construction as the fuel tank and same corrosion, same place. Fixed by welding the holes and adding reinforcing plates to the bottom.

If I were to guess, you probably have the beginnings of a leak and it won't get better!

Mark

 

[centerline]

Re: How Many of Your Still Have the Original Metal Fuel Tank

1977... still original steel tank.

 

[B757Captain]

Re: How Many of Your Still Have the Original Metal Fuel Tank

Should have added - both tanks 5052 aluminum.

Mark

 

[woodster]

I am asking because I am getting concerned about mine. I don't see any obvious signs leakage. But of late, my bilge water has a bit of an oily feel to it. I don't see any oil sheen on the outside water surface when I pump the bilge. But the pump doesn't take all out to the bilge surface level. And oil floats. But then when I then sponge the bilge completely dry, the squeezed out water from the sponge over the side does show some oil sheen on the surface. No diesel odor however.

I am thinking that my tank is showing the very first signs of leaking from the bottom and I can't yet see the route the slow drip is taking to the bilge. Not enough to identify for sure yet.

put some red dye in the fuel and then watch for traces in and around the tank and hull.....i put a new bottom on mine back in the summer and it should be good to go for a while ...maybe 15 to 20 years more it was 35 years old this summer

 

[centerline]

put some red dye in the fuel and then watch for traces in and around the tank and hull.....i put a new bottom on mine back in the summer and it should be good to go for a while ...maybe 15 to 20 years more it was 35 years old this summer

whats even better is go to napa auto parts and get a small container of untraviolet fuel/oil dye... a very small trace of the dye will show up under a black light as a streak of florescent green.... very easy and quick to tell with absolute certainty if you have a fuel leak, and where it is...

 

[sandpiper10471]

Re: How Many of Your Still Have the Original Metal Fuel Tank

Still on the original 1981 tank. All my boats have at some time given the indications you mention but I think the bilge contaminant has come from fuel which has managed to get below the engine pan and slowly washed down into the bilge. Those "spills" will have come from events such as excessive engine bleeding, changing of fuel hoses, sloppy oil changes, flooding of the pan which has allowed collected residues to flush away to the bilge etc.

 

[woodster]

whats even better is go to napa auto parts and get a small container of untraviolet fuel/oil dye... a very small trace of the dye will show up under a black light as a streak of florescent green.... very easy and quick to tell with absolute certainty if you have a fuel leak, and where it is...

man that is good to know...... its great to have hi-tech in the tool bag.....i wonder if they make an LED black light

 

[centerline]

man that is good to know...... its great to have hi-tech in the tool bag.....i wonder if they make an LED black light

yes they also have blacklights to sell for using with the dye... in a basic flashlight version that is kind of expensive, or a larger version that is really expensive.

i use a regular "plug in to the wall" florescent light like you will find at home depot.... it is much brighter than the ones you buy that are associated with dyes, although a bit more delicate..


but as has already been said in an earlier post, it may not be fuel, but if it is the fuel may not be leaking from the tank....
check the weep hole in the lift pump for seepage, as the diaphragm could be ruptured.... or elsewhere for a loose clamp or fitting...
also check for a loose oil filter, or faulty(dripping) oil sensor...
even though thngs may have been fine since the last time we checked with out leaking, age has a way of allowing things to happen that we dont want to happen...

 

[rardiH36]

All: Thanks for the good info.

I also didn't know about the uv dyes for fuel leak purposes.

I will take a look at the other potential sources suggested. However, fuel leaks like from say the fuel pump diaphram I would think would congregate in my drip pan under the engine .... which is OK in respect of any liquid accumulation ... rather than in the bilge.

Another possibility is that the seal at the transmission to coupling area is beginning to fail. Transmission fluid I guess could flow down towards the shaft. Drips there might "miss" going into the drip pan under the engine and instead migrate to the bilge as does the any water that gets through the stuffing box. Transmission fluid doesn't have much of an odor which is the case with my mystery oily feel to the bilge water.

I will do another look-see. But if nothing obvious, I think I will just monitor for a while just in case I might have misdirected some oil during my last oil change a few months ago.

Then will follow the suggestions that you all have made.

Thanks

 

[JimBr]

Re: How Many of Your Still Have the Original Metal Fuel Tank

1981 Hull 143 37C, I still have original aluminum tank. I've seen similar signs and think it is weepage from engine. I did notice a leak from fill hose, near nozzle fitting when I was filling tank for winter. I suppose there could be other leaks close to tank.
Jim Bridgens

 

[centerline]

Re: How Many of Your Still Have the Original Metal Fuel Tank

not that it matters, but in almost every case, an aluminum fuel tank will corrode from the outside in, whereas a steel tank will corrode from the inside out.... a small amount of water inside a steel fuel tank will rust just as quickly no matter if there is fuel in it or not.
it takes a bit longer for the rust to take ahold, but once it does its usually only a matter of time.
aluminum tanks hold up much better with a small mount of water inside of them, but due to galvanic action/salts/air, they are more susceptible to corrosion from the outside.

any condition that allows for damp then dry, repeatedly, will speed the corrosive effects....

 

[RTB]

We still have the original tank too. So far so good.

I think you would see signs if leaking.

About that fuel boost pump - you would never think a leak would get to the bilge, but it does. I found diesel in the bilge in Panama City (Florida) during our cruise from Texas. Once I finally located the leak and replaced the pump, no more diesel in the bilge. I still don't see how it gets in there.

She's a great old boat. After 2 years of cruising and 5000 miles, the leaking fuel boost pump has been our only repair.



Before we left our home port, I had an access panel installed.



The tank was cleaned and inspected, and filled the tank with 30 gallons of clean, fresh diesel. The guy I had do the work pointed out where the low spot was (indicated by some pitting) inside the tank, and says that is where the tank will eventually give out.

Good luck finding the leak.

Ralph
http://www.sailblogs.com/member/brogdon/

 

[centerline]

About that fuel boost pump - you would never think a leak would get to the bilge, but it does.
Once I finally located the leak and replaced the pump, no more diesel in the bilge. I still don't see how it gets in there.


Ralph
http://www.sailblogs.com/member/brogdon/

the lift pump is manufactured with a small weep hole in it, like a water pump has.... the weep hole on a water pump is an indicator to tell you when the seal goes bad so you can change it before the bearing goes out also... when it begins to weep, the seal is bad..

the weep hole on a lift pump is there as a safety, and an indicator, when its leaking, that the diaphragm in the fuel pump is worn and ruptured...
as a safety, it allows any fuel that gets thru the worn diaphragm to escape to the atmosphere/bilge, rather than being leaked into the crankcase where it can go unnoticed and cause oil dilution and damage...

 

[RTB]

True, but my comment was in reference to Rardi saying " However, fuel leaks like from say the fuel pump diaphram I would think would congregate in my drip pan under the engine."

I'm just not sure how a fuel tank leak could be anything but obvious. It is pretty accessible to inspect, unlike where the fuel pump is on our boats. I could be wrong, since he has a different Yanmar than my 3 GMD if I recall?

Ralph

 

[rardiH36]

True, but my comment was in reference to Rardi saying " However, fuel leaks like from say the fuel pump diaphram I would think would congregate in my drip pan under the engine."

I'm just not sure how a fuel tank leak could be anything but obvious. It is pretty accessible to inspect, unlike where the fuel pump is on our boats. I could be wrong, since he has a different Yanmar than my 3 GMD if I recall?

Ralph

A small pin-hole leak at the bottom of my fuel tank, the way and where the tank is mounted, could very possibly make to the bilge without me being able to observe where I can see.

Galvanic corrosion from the outside is something that I have wondered about. The tank is aluminum painted a ugly green color. The tank is secured with stainless steel straps around it anchored to the FRP liner. SS against aluminum as we all know isn't the best of combinations.

Being in California, we don't have much atmospheric humidity. I have never had any issue with water contamination in the diesel fuel. Hard to imagine that an aluminum tank would corrode from the inside. But again its 35 years old.

The source of the oil feel to the bilge water will be discovered I am sure!

 

[Ed Schenck]

Re: How Many of Your Still Have the Original Metal Fuel Tank

My 1979 H37C tank has no straps. It is just tabbed to the hull, the only place I can see any kind of anchoring. Without removing lots of interior there is no way to see the bottom seams.

 

[tmjb]

Mine is a 1980 H36, hull #78. I just bought her and haven't used the tank yet other than to start on the hard. Tank seems OK.

 

[Seagull8481]

Re: How Many of Your Still Have the Original Metal Fuel Tank

My 1980 H37C fuel tank has no leaks. I drained and inspected it when I bought the boat from my brother in 2012 and it was clean with not issues.
My brother was very good about keeping the tank full of fuel during winter idle months and adding fuel stabilizers. It worked so I'm following his practice.

Mike S/V Dios Piratas