Need guidance on 30 Year old Fuel Tank

[piosifid]

I own a 24' Skipjack Fisherman that I purchased new in 1991. I have seen a few topics on old fuel tank failures and decided to take a closer look at mine after removing most of the fuel from the tank. The boat has always been trailered and resides in a low humidity environment. There is a fuel water separator filter installed on the boat that I replace every season. I also use a fuel additive regularly to break down any water that gets into the fuel. The first thing I noticed after removing the access panel to the tank is that it is foamed in which is not usually done any more. The tank was built by Berry's in Costa Mesa, CA. and it looks like it was a good installation. The sticker on the tank says it is 112 gallons. Surprisingly, the foam is rock hard and there is no sign of any water intrusion of fuel odor. I then removed the fuel level sending unit to get a better look inside the tank. Unfortunately, you cannot see all the way back to the fuel pickup tube due to the baffles inside the tank. But I was able to get a good look at most of the tank and get a few pics as well. There are some small pieces/debris that were probably introduced with the gas over the years but overall I thought the tank looks like it is in descent shape. I attached some photos and would like your opinions on what you would do if this was your boat? Does this tank have more life in its current condition or what are the next steps that I should consider? I appreciate all you input.

Thanks,

Peter

 

[Chris1956]

Aluminum tanks tend to develop pinhole leaks on the bottom, lowest corner, usually the stern side. That is likely where your damage will be.

Can you get the tank out to inspect the condition of the aluminum?

 

[piosifid]

Aluminum tanks tend to develop pinhole leaks on the bottom, lowest corner, usually the stern side. That is likely where your damage will be.

Can you get the tank out to inspect the condition of the aluminum?

I decided to take one additional step to inspect it. I am going to remove the fuel pick up tube and use a borescope to get a better look. This should be sufficient to make a more definitive decision on the true condition of the tank. If I determine I have to pull the tank out to inspect it more throughly, I would just replace it at that point. More to come. I need to go guy a borescope now. Thanks, Peter

 

[Horigan]

Seems like a pressure test would give you better insight on the tank integrity than just a visual inspection from the inside.

 

[piosifid]

Seems like a pressure test would give you better insight on the tank integrity than just a visual inspection from the inside.

I think you are correct, I intend to call the manufacturer today and get their advice on how to perform the pressure test. Thanks, Peter

 

[mike_i]

I would say your tank is fine. As long as you don't see corrosion or smell gas you're fine. I would get rid of any foam that is in contact with the tank so it has good airflow around it. It wouldn't hurt to do a compression test if it would make you feel better. I assume the crap in the tank is normal and can be pumped out but your filters will prevent it from getting sucked into the motor. I had to replace my tank because of the water trapped between the foam and tank causing pinhole corrosion. Berry's did my tank and it's been fine for over ten years now. Using a borescope is fine but If your tank has any corrosion it would be from the outside. If you need any help hit me up, I'm local to you.

 

[piosifid]

Seems like a pressure test would give you better insight on the tank integrity than just a visual inspection from the inside.

I talked to the tank manufacturer. They said there is probably some water underneath the bottom of the tank towards the back that you cannot see and is the most typical place where corrosion starts. They did say a pressure test is a good idea but can only prove the tank is good at that moment without any indication of how long it could last. After this discussion with them, I think I will take one additional step before making any firm decision to move forward with a tank replacement or not. I intend to remove some of the foam at the back of the tank all the way down to the hull bottom and see if there is any moisture at the "V" bottom. If it is still dry there, the pressure test and visual borescope looks good I'll probably call it good and check it more often for any signs of deterioration. More to come.

 

[Chris1956]

Yes, that is why I recommended you visually inspect the bottom aft of the tank. If the pitting is almost, but not quite thru the tank, it will pass visual inspection from the inside and pressure test, and then leak next spring.

 

[dingbat]

You need to remove the tank completely from the "mount" to inspect.

Aluminum is very corrosion resistant as long as oxygen is present to maintain the aluminum oxide layer. Issues begin when an area becomes devoid of "regenerative" oxygen.

The primary area of concern is between the bottom of the tank and support brackets (typically wooden) underneath. Quite often the tank sits on strips of neoprene rubber to minimize abrasion. It's the area between the tank and the lower supports that trap mositure over time, creating an area devoid of oxygen, which in turn starts the corrosion process. Aluminum corrosion (pock marks and white powdery residue) are easily identified.

 

[tpenfield]

The main issue/risk would be what you cannot see . . . namely what, if anything, is going on with the foam that surrounds the tank.

A pressure test might help, but a visual inspection of the under side of the tank would be so much better. Often fuel tanks are removed from the boat for a full inspection and pressure testing (low pressure 3-5 psi) and then determined if they can be returned to service.

 

[piosifid]

You need to remove the tank completely from the "mount" to inspect.

Aluminum is very corrosion resistant as long as oxygen is present to maintain the aluminum oxide layer. Issues begin when an area becomes devoid of "regenerative" oxygen.

The primary area of concern is between the bottom of the tank and support brackets (typically wooden) underneath. Quite often the tank sits on strips of neoprene rubber to minimize abrasion. It's the area between the tank and the lower supports that trap mositure over time, creating an area devoid of oxygen, which in turn starts the corrosion process. Aluminum corrosion (pock marks and white powdery residue) are easily identified.

I started to remove the foam at the back of the tank and as expected about half way down I could see evidence of corrosion (white powder) on the surface of the tank. it got worst the farther down I went. I removed all the foam from the rear of the tank and there was definitely some moisture down there. No standing water but enough to raise concerns, not so much on the back side of the tank that I could see, which may or may not be bad enough to replace the tank. But the concern is on the bottom that I cannot see without removing the tank. So I made the decision to remove it and replace it regardless of how it looks when I get it out. I'm not putting a 30 year old tank back in when most of the the effort (cost) is the labor to remove the tank. I'll post some pictures of the condition after I get it out.
I'll probably get a new one from Berry's unless someone has any suggestions of someone local to San Diego that builds thanks. Thanks, Peter

 

[Chris1956]

Tiempo and others make a pretty good selection of standard fuel tanks. See if you can get one close to the original size. Stock tanks will be much less $$ than custom.

 

[piosifid]

I started to remove the foam at the back of the tank and as expected about half way down I could see evidence of corrosion (white powder) on the surface of the tank. it got worst the farther down I went. I removed all the foam from the rear of the tank and there was definitely some moisture down there. No standing water but enough to raise concerns, not so much on the back side of the tank that I could see, which may or may not be bad enough to replace the tank. But the concern is on the bottom that I cannot see without removing the tank. So I made the decision to remove it and replace it regardless of how it looks when I get it out. I'm not putting a 30 year old tank back in when most of the the effort (cost) is the labor to remove the tank. I'll post some pictures of the condition after I get it out.
I'll probably get a new one from Berry's unless someone has any suggestions of someone local to San Diego that builds thanks. Thanks, Peter

The tank is out and there is corrosion on the bottom half on all sides and the entire bottom. Corrosion varied from medium to heavy but it was not yet leaking. Who knows how much longer it would have lasted. I am now looking to get a new tank built.

 

[dingbat]

The tank is out and there is corrosion on the bottom half on all sides and the entire bottom. Corrosion varied from medium to heavy but it was not yet leaking. Who knows how much longer it would have lasted. I am now looking to get a new tank built.

Hard to tell how bad with all the mold still in place, but it doesn’t look good.

Pretty good witness as to why foaming a tank in place is frowned up

 

[piosifid]

Hard to tell how bad with all the mold still in place, but it doesn’t look good.

Pretty good witness as to why foaming a tank in place is frowned up

Here are some pics of the corrosion on the tank after a little clean up. It was more than 75% corroded through in a few areas. I took the old tank to American Tanks and they are now building me a new one.

 

[piosifid]

Now that the new tank is being built I turned my attention on how the water intrusion occurred in the first place. After removing all the old foam around the tank it was clear that the majority of the water intrusion occurred through two cutouts on the right and left stringers that I believe do not belong there. The water goes through the cutouts to the sides and underneath the tank all the way back to the rear bulkhead in front of the engine. Unfortunately, this includes all the foam underneath the fish box as well. I intend to fill the cutouts and seal the area to avert any water intrusion occurring from this area in the future. The next project is to remove the fish box along with all the foam around it and underneath it as is likely to be more soaked since it is further back in the cavity.

 

[Commander_47]

Wow, this is a great thread. Although I'm sorry you have to do a new fuel tank. Ironically, I have the exact same tank as yours. A 1989 Berry in my boat. Same size as well. I have absolutely NO issues with it at all. In fact, it is amazing in my opinion.

Having said that, and in my humble opinion, it looks like your Berry tank was installed in a manner that created a water trap. My tank is NOT surrounded in foam. In fact, it sits on a shelf designed into the hull that raises it above the bilge by over a foot. It is designed in such a way that ANY water will drain into the bilge to be sucked out. There is no way outside water can get to my tank unless the boat sinks.

In img 1706, it looks to me like a drain was designed into your boat to trap water under the tank!!!! In img 1707 there should be some sort of drain in the low V to allow the water out.

I"m not sure of the purpose for the foam. Seems to me that removing it all would be better for the tank. But it looks like the foam is fiberglassed in, so I'm not sure how to recommend you do that to your boat without more pictures of the installation.

 

[piosifid]

Wow, this is a great thread. Although I'm sorry you have to do a new fuel tank. Ironically, I have the exact same tank as yours. A 1989 Berry in my boat. Same size as well. I have absolutely NO issues with it at all. In fact, it is amazing in my opinion.

Having said that, and in my humble opinion, it looks like your Berry tank was installed in a manner that created a water trap. My tank is NOT surrounded in foam. In fact, it sits on a shelf designed into the hull that raises it above the bilge by over a foot. It is designed in such a way that ANY water will drain into the bilge to be sucked out. There is no way outside water can get to my tank unless the boat sinks.

In img 1706, it looks to me like a drain was designed into your boat to trap water under the tank!!!! In img 1707 there should be some sort of drain in the low V to allow the water out.

I"m not sure of the purpose for the foam. Seems to me that removing it all would be better for the tank. But it looks like the foam is fiberglassed in, so I'm not sure how to recommend you do that to your boat without more pictures of the installation.

The 1707 picture is after the foam was removed, see pic of it before I removed the foam. I am interested in your tank not being foamed in and wonder if it is the second tank in that boat. What is the date of manufacture on the tank sticker? Did you buy the boat new? The shelf concept a foot above the bilge must have reduced the tank capacity. How many gallons does it hold? That should be stated on the tank sticker as well. Glad to hear yours is in great shape. I would not wish the job of removing a foamed in tank on anyone. It is a bear of a job. I also included a couple pics of the fiberglass repair I did to seal off the holes that allowed water into the tank cavity in the first place. I am in the process of removing the fish box now and will post pics of that as well. I am curious that you mention that your tank cavity drains into the bilge. My tank/fishbox cavity is one allowing for both to fit in one cavity but there is no drain from this cavity. There is a bulkhead that separates the engine from the fishbone/tank cavity without a drain. Which makes sense in that you don't want water coming from the bilge underneath the engine going forward into the fishbone/tank cavity?

 

[Commander_47]

I spent the past couple days at my boat, and took some pics to show you my tank. My tank is in a 33 year old 26 foot cruiser I keep in great running order. It is used regularly and looks a little rough, but everything works and runs great.

The tank sits long the port side and is pretty high above the bilge. it is bolted in with welded on tabs. No rust at all. I just flushed and cleaned it last season.

You will notice that mine seems to have a better drain system. The center motor stringers have drains that let water seek the lowest point in the keel.

Any water entering the bilge is funneled straight down to the lowest point where my bilge pump is. Absolutely no water, never, not ever collects around the tank. In fact, I never have water in my bilge at all, ever.

You may want to consider mounting your tank on stringers that lift it up off the bilge, and then make sure there are drains to let the water out.

Water from the deck will run down into bilge just from being on the water.

 

[piosifid]

I spent the past couple days at my boat, and took some pics to show you my tank. My tank is in a 33 year old 26 foot cruiser I keep in great running order. It is used regularly and looks a little rough, but everything works and runs great.

The tank sits long the port side and is pretty high above the bilge. it is bolted in with welded on tabs. No rust at all. I just flushed and cleaned it last season.

You will notice that mine seems to have a better drain system. The center motor stringers have drains that let water seek the lowest point in the keel.

Any water entering the bilge is funneled straight down to the lowest point where my bilge pump is. Absolutely no water, never, not ever collects around the tank. In fact, I never have water in my bilge at all, ever.

You may want to consider mounting your tank on stringers that lift it up off the bilge, and then make sure there are drains to let the water out.

Water from the deck will run down into bilge just from being on the water.

I originally thought you had the same boat as well which is what made me curious about your tank installation. Your configuration looks to work very well. Mine is a little different in that it gets plenty of water in the bilge as we are always washing down the deck with water from the fishing. Some water drains out the scuppers and some winds up in the bilge.