Replace Fuel Tank Advice

[Cinnamon Girl]

Anyone have experience/advice about replacing fuel tanks? We have a 1980 boat with the original aluminum fuel tank - 120 gallon. It has no inspection plate. The boat is new to us and we had someone look at it to determine if the inspection plates could be added. He advises that the typical life of that tank is just 20 years and we may want to consider new tank(s). Of course, removal alone is very involved....and it appears that the water tank is also original. We will liveaboard within the next couple of years and have plans to travel somewhat extensively with the boat. In otherwords, we will likely depend on both water and fuel.

Anybody ever undertake the project themselves? Neither tank is leaking now-should we wait until they do? What have you paid to have a project like this done? Our guy says to fabricate the tanks would be about $1000 each and then 3x that to install each. Geez, that is really gonna eat into the kitty!

Any advice would be appreciated.

[rebel heart]

I have a 35 year old black iron tank that's still in top form, for whatever that's worth.

[CarinaPDX]

I've removed an aluminum diesel tank and a stainless kerosene tank (both with small leaks) and am looking to replace them.

I really like the idea of polyethylene (PE) tanks, but these are no longer available custom in the US for fuel. By law, effective last year, fuel tanks must meet low permeability (LP) standards. The mass-produced rotomolded PE tanks apparently have an inner layer which seals them to LP standards; apparently straight PE doesn't meet the standards. (If anyone knows better, or has anything to contribute I'd like to know!) In any event the usual custom welded-PE vendors are out of the fuel tank business.

Aluminum is supposed to be one of the best materials for diesel. I got some water in the tank which supported algae. When the biocide killed the algae, the dead algae floated between the water at the bottom and the diesel. That became corrosive and ate a line around the inside of the tank. Not good...

The stainless tank had a flat bottom, and collected a thin layer of water on the bottom which caused some corrosion. It was slowly leaking through the welds.

Perhaps black iron would be better?

[David_Old_Jersey]

Originally Posted by Cinnamon Girl

Anybody ever undertake the project themselves?

Nope. But it was one of the things I made sure had already been addressed by a previous owner (on my boat it's an engine out job).

Neither tank is leaking now-should we wait until they do?

I would wait until you have problems (and keep my fingers crossed that problems start with only a weep and not a full on seam failure ) - but a bit of thinking ahead don't do no harm.

120 gallons sounds a lot, could maybe replace with a smaller tank (or tanks) for easier fitting. or could cut open the tank and fit a bladder tank inside - same for the Water Tank....might need to get custom made? or settle for a bit less capacity?

[DeepFrz]

I have to disagree with David. Don't wait until you have problems. You may not have to rush into changing your tanks, but you should really cut holes in the tanks, drain and clean them and ensure that they are either in good shape or need replacing. A boat with a leaking diesel tank will be a miserable place.

[boden36]

If it aint broke, don't fix it. But do inspect it as Deep Frz suggests. Maybe you could use one of the remote inspection scopes that can be purchased reasonably cheaply or perhaps hired. This would only need a small opening in the tank.
Regards,
Richard.

[DeepFrz]

Something I didn't bring up in my earlier post is that if there are no inspection ports in the tanks then you can be pretty certain that the tanks have never been cleaned since they were installed. An inspection scope isn't likely to tell you much, other than you have a whole pile of crap in your tanks. Both water and fuel tanks will have to be cleaned in any case. Unless, of course, you want to risk a clogged fuel line in a sea way or poison yourself with fetid water.

[Target9000]

We pulled the fuel tank (and the fuel bladder) and installed new fuel tanks in our Westsail 32 last summer. I can say that the job is most likely going to vary in difficulty wildly between models of boat so what you really want to do is find someone that has done it in YOUR boat and ask them about it.

A 120 gallon fuel tank is also likely to be baffled which may cause problems when you try to cut out an inspection port.

When we replaced our tanks it really wasn't all that hard. The hard part is getting everything out of the way so you can get to the tank. Once again, check with another owner that has done it.

We went with aluminum tanks for replacement. We painted them over with an epoxy coating to protect them from water and corrosion.

[Mike OReilly]

Originally Posted by David_Old_Jersey

or could cut open the tank and fit a bladder tank inside

Anyone have any experience with this solution? I'm thinking of attempting this. Other than losing some tank volume to the bladder, any other reason not to try this?

My situation is I have two black iron diesel tanks. Both were inspected and cleaned before we bought the boat. The main one (90 gallons) is good, but the smaller one (45 gallons) has a small leak, so we've decommissioned it.

[SabreKai]

Sabre Dance had one 40 gallon steel tank. 15X15x40 long that lived under the stbd side cockpit seat and side deck. Access was only via cutting away a lot of stuff in the cabin. Since that was part of the plan, no problem. Once that was done I determined that getting it out by shoving it forward would be a monumental pain, and since the engine (which was to be replaced as well) wouldn't fit out the companion way hatch, I had an access cut into the cockpit sole and it took 15 minutes to haul the tank up and out. 6 foot nylon strap, a chain hoist attached to the forklift extensions and it was gone. I am blessed with a pretty wide open space for that sort of stuff but the cockpit access made a huge difference. I am replacing it with a 60 gallon stainless tank.

A $1000 a piece seems reasonable, that is the price that I have been getting for my water tank, but 3X that to install? Outrageous.... Unless you dont' have the skills to do it yourself. In that case you either learn them, find a buddy who has them, or pay the nice man to do it while you nurse the pain with a rum punch.

[bck73]

Hi heres a company you might like to try for a tank
Tek-Tanks - Custom made or standard fit water, waste and fuel tanks

rgds
Bck73

[CarinaPDX]

I saw some Tek-Tanks while I was in Europe. They are works of art. Just a pain to get shipped into the States.

[bck73]

I've not got one myself I was enquiring about them as my fuel tank has no access hatch. And like you said they look roburst.

[donradcliffe]

Does your tank have a level guage?? Usually you can remove them to check the inside of the tank.

[ovrmyhead]

I am going through the leaking fuel tank blues as we speak . I say cut inspection ports and clean it out before you get ahead of yourself and start thinking of replacing. You should be able to locate the baffles ahead of time just by tapping with a hammer, you will hear the tone change when you hit the tank at those spots. I really wanted to repair my tank but alas, it is just too far gone. I dont want to take the time yet for a custom build so I am losing some capacity and going with one of these.
Moeller Marine Online - Home - Home Page
I'm placing a second tank in my stern hold to make up for some of the loss.
I cut my inspection ports with a grinder, but picked up a sawsall to chop it up. I tried it out last night and that sawsall cuts through that black iron tank like butter. I'll try and get some pictures posted on the blog this evening.