Fuel Tank replacement

We have an 1980 36' Albin with steel fuel tanks that will need to be replaced soon. A thought come to me today that I could use the two stainless steel water tanks in the lazerette as the fuel tanks. I could then cut out the existing fuel tanks and use those spaces for bladder water
tanks. Has anyone done similar? Is it doable?

SelahWay said:

We have an 1980 36' Albin with steel fuel tanks that will need to be replaced soon. A thought come to me today that I could use the two stainless steel water tanks in the lazerette as the fuel tanks. I could then cut out the existing fuel tanks and use those spaces for bladder water
tanks. Has anyone done similar? Is it doable?

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There are a couple of thoughts that come to me off hand. First fuel tanks must be certified as fuel tanks, thickness, baffles and pressure testing, maybe other things that I am not remembering right now. They have to have approved fuel hose for fill, vent, supply and return. You would have to add supply dip tubes and return line. Then you might have fittings on the bottom of the tanks which may or may not be legal. Plus you may kill the resale value of the boat. You might have a problem with your insurance, or maybe not, I would ask them.

I am waiting to haul my boat for the winter and then will pull one engine to replace one fuel tank. It will cost about $2500 for a new .25” 5052 aluminum tank with a 210 gallon capacity.

Personally I would just replace the existing tank with aluminum and install it properly and then you will be done for the rest of your lifetime.

That's a possibility, but is there any advantage in the long run vs just replacing the fuel tanks? Where are the current fuel tanks located in the boat?

Comodave said:

I am waiting to haul my boat for the winter and then will pull one engine to replace one fuel tank. It will cost about $2500 for a new .25” 5052 aluminum tank with a 210 gallon capacity.

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Ouch. That price makes me hope my existing aluminum tanks (.190 wall 5052) last forever, as they're that same size, so just as pricey to replace if ever needed. Fortunately, mine are mounted well above any bilge water and in good shape everywhere they can be inspected. But they sit on a board, so I can't see the bottom side of them.

Two wing tanks on a single screw FL120

SelahWay said:

Two wing tanks on a single screw FL120

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What's above and around the tanks? It might be possible to make a floor hatch near or above the tanks where you can move and possibly tilt the tanks to get them in / out of their current spot in one piece. Depending on size vs doorways, getting them in and out of the boat might be tricky, but it's likely possible unless the tanks are huge.

You can always cut them up in place and put in a couple of smaller tanks and hook them together if you can’t get the old tank out and new one in with the engine in place. I have 2 tanks outboard of my twin engines so I have to pull the engines one this year and one next year over the winter in order to replace my fuel tanks. Mine are steel and not leaking yet but they are 32 years old. So I want to replace them while I am still young enough to be able to do it...

I am in the process of having two steel 200g (each) saddle tanks replaced with four 100g fiberglass tanks. With all the fittings, hoses, vents, and such, about $5000 installed, though this is in Mexico.

You will never be able to use your water tanks as water tanks again, so there's no going back. My hunch is you will lower your resale value more than $6k by doing this. I personally, wouldn't even look at a boat where the owner made this decision, and I'm not that fussy. Maybe this is your last boat and you don't care, but otherwise, something to think about.

I had a custom fiberglass fuel tank made for a previous boat. It was 565 gallons and honestly I gave up accounting for what it cost in total. They had to cut out the cockpit deck and the rear of the aft cabin to get the new tank into the boat. They cut up the old tank to get it out.

I have the same boat and issue. First I wouldn't use older stainless water tanks for fuel, second it's fairly easy and not too expensive to simply replace the steel fuel tanks with poly tanks of less capacity. My plan is to replace the port and starboard 175 gallon tanks with 99 gallon poly tanks, replace my toilet system with a composting toilet and put a 55 gallon tank in the bilge forward of the engine. For my use 350 gallon capacity is unnecessary as I usually run at 6kts using 1.5 gallons an hour gives me about a 1000 mile range. The tanks can be had for about $2000.00 and with bits and pieces I figure the project will cost under $3000.00.

I just had another fuel tank go out . That’s two this year plus a water tank . I’m down to three fuel tanks now, 200 gallons total capacity. I’m hoping these three will outlast me.

Comodave said:

I had a custom fiberglass fuel tank made for a previous boat. I gave up accounting for what it cost in total.

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The biggest issue I had with going fiberglass was figuring out the fittings, especially the clean-out ports. Traditionally, aluminum fittings are installed with the plates thru-bolted into the tank. That results in well over 100 'wet' penetrations (meaning below fluid when full). I ended up using oil & gas fiberglass pipe fittings, which are used for caustic fracking solutions and withstand up to 150 psi. These were glassed into the tank with zero fastener penetrations.

mvweebles said:

The biggest issue I had with going fiberglass was figuring out the fittings, especially the clean-out ports. Traditionally, aluminum fittings are installed with the plates thru-bolted into the tank. That results in well over 100 'wet' penetrations (meaning below fluid when full). I ended up using oil & gas fiberglass pipe fittings, which are used for caustic fracking solutions and withstand up to 150 psi. These were glassed into the tank with zero fastener penetrations.

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How big are the O&G pipe fittings? Large enough to get an arm in the tank or just a wand? Any pics of this setup? Interesting.

Sailor of Fortune said:

How big are the O&G pipe fittings? Large enough to get an arm in the tank or just a wand? Any pics of this setup? Interesting.

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Largest I found online was 20" opening, so big. The only complaint I have is the thickness - the flange is almost 1" thick, and the cover is also almost 1" thick. I had the fabricator weld the bolts to a ring. Two pics attached - one is the tank. It's 100g and looks small because the fittings are relatively large - 9" in diameter (opening is 6"). Bolts are 7/8" SS from McMaster Carr (Buna-N gasket material from them too). Note the 1" glass fuel fitting at bottom which is also glassed-in. Fabricator used old tank as pattern and the fit ended up being really tight. I doubt I lost more than 5-gallons of capacity. Pipe fittings came from a place called "Century." The flanges/blinds were about $90/each. Note in the schematic below, the RED scribbles showing the fiberglass fillets which isolate the bolts on the "dry" side of the envelope, thus no penetrations for mounting screws or bolts.

Frankly, I was surprised at how little information I found online for Fiberglass tanks. Several small DIY-types.

For some reason, I could only attach one picture. Will post second pic in separate post.

Second picture. Tank under construction.

I just had two poly 80 gallon each tanks installed on my boat. My refit guy was resistant to the idea but I wanted increased capacity and peace of mind with older 50 gallon aluminum tanks - 50 years old - gone. When he took the tanks out and left them out in the sun, a very small seepage was discovered, very slow but very constant. The warmth from the sun created expansion in the tank and the leak moved beyound seepage.

I too added a composting toilet to replace the old style head with no holding tank. The front fresh water tank was removed and replaced by two smaller poly tanks. When that tank was removed and drained (again 50 years old) all kinds of crud came out. The fresh water tanks were moved further astern as I had added a bow thruster and needed the room for the unit and batteries, two Fireflies providing a longer run time for the thruster and windlass. I changed out my four golf cart batteries and replaced them with Fireflies.

When I had the fiberglass tank made, they put the clean out ports on the top. All the penetrations were on the top of the tank. The tank sloped down as it went forward and the fuel pickups went down into the deepest place in the tank so the fuel would take anything in the tank out and be caught in the filters.

Comodave said:

When I had the fiberglass tank made, they put the clean out ports on the top.

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I tried to get there, but I have serious obstructions above the tanks (cabinetry, settee, etc.). Creating access to each baffled chamber would have been difficult. Finding the pipe fittings, designed for 150psi, made me comfortable with side-mounted access ports.

The lower 1" tank fitting in the picture is the cross-over to combine two tanks to act as a single tank. I also agonized over this as there were issues with each permutation I could come up with. Four separate tanks would mean more deck fills and many more valves that I find confusing and non-intuitive when needed. In the end, I pinged Steve d'Antonio and he described its pretty common to gang-together pairs of tanks with bottom fittings and are acceptable as long as they have shut-off valves and are protected from accidental strike or step. Yet another boat-related compromise.

I have the same boat as you. Fortunately, the P.O. had the tanks done to the tune of about $10,000. The engine came out , then one tank then the other. They cut the bottoms off the tanks, added new bottoms and reinstalled. Wish they would have added inspection/clean out ports but they didn't.

I guess I wouldn't consider using the water tanks for fuel. I have heard that the Taiwan Stainless Steel was not very good and I am not totally certain I don't have a small leak in one of the seams on the water tanks. I don't really care about the leak. I can't see most of the tanks and water is cheap around here.

Funny thing though.. I had to remove my whole boat water filter. It would clog every couple of tanks of water. Now I have to clean the screens on my faucets every couple weeks. Looks like rust particles. Copper and plastic water lines, where is the rust coming from? All I can think of is the welded seams.

pete

These responses have been very helpful ... so, the original thought is now out the window. We'll have a lot to think about and plan for replacement: time, material, construction, de-construction, dollars, etc, etc, etc.

Is your boat a single or twin engine? With a single you may be able to cut up the old tank and slide a couple smaller tanks in. I have twins and there isnt even room to cut up the old tanks with the engines in. I am going to replace one tank over the winter but will have to pull one engine and stack it over the other engine and then I will have access to get to the tank. Not sure yet if I can get it out in one piece and get the new one into the engine room or will I have to go with 2 new tanks. Waiting on getting our boat hauled out so I can get to work on it. Then next year I will do the other tank.

SelahWay said:

We'll have a lot to think about and plan for replacement: time, material, construction, de-construction, dollars, etc, etc, etc.

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Although my quotes are from Mexico where labor is much less expensive, I'll offer the blow-by-blow as an example. Although labor is cheap, some materials are more expensive - proper alloy aluminum comes from the US so is roughly +20% more expensive. For me, fabrication, installation, and materials for Fiberglass tanks (excluding fittings, which were over $1000) was $3500. Engine was removed anyway to install a generator and do some rewiring, but would have been around $800. So all-in, from scratch, around $5500-$6000. US boatyard labor rates would send this well north of $10k.

I did get quotes on 0.25" aluminum of the proper alloy (I forget what number). Although the material is much more expensive, the labor is quite a bit lower because the fittings can be easily welded in place. The fittings are about the same cost. Overall, from the quotes I received, price would have been slightly higher for aluminum. In the US, fabricating in aluminum would be much less expensive because materials are less expensive and requires less labor.

With all due respect for the other Albin 36 owner who posted prior this (PO replaced the bottoms of the tanks), if you go this route, consider replacing the entire tanks - welding a new bottom only is a bit of an unnecessary short cut given all the work to get the tanks out. I'd bet the current owner in hindsight would gladly pay an add'l $3k to have had new tanks, not just replaced bottoms.

For me, an easy decision. Fiberglass is forever and was roughly same price as aluminum in Mexico. No worries about leaking deck-fills and water puddling on top of the tank, etc.

Good luck!

5052 is the recommended aluminum.

I have a 1986 Albin 34. It had a single 200 gallon tank, that leaked. My budget is tight, so rather than pay to remove the engine or cut up a section of the floor, I took the old sawzall to the old tank and spent a few hours cutting it up into manageable pieces and removed it. I then put in two 50 gallon tanks and plumbed them up. Tanks were about $300 a piece and another $300 for plumbing parts. It cuts my cruising distance in half, but with a single diesel and mostly doing intracoastal trips it creates no problems for me.

Legality

Earlier in this thread somone said "First fuel tanks must be certified as fuel tanks, thickness, baffles and pressure testing, maybe other things that I am not remembering right now. They have to have approved fuel hose for fill, vent, supply and return. You would have to add supply dip tubes and return line. Then you might have fittings on the bottom of the tanks which may or may not be legal."

I curious about the "Legal" part of this. Is this really a law? Passed by our elected officials? Or, is is a rule, enforced by the Coastgauard? "Prepare to be boarded and have you fuel tank fittings inspected!". Or is it a rule for new boat manufacturers? Or a recommendation enforced by your insurance company? What are we really talking here?

Andrewc - You're comment is encouraging, couple questions.
- What material did you use for the new $300 tanks?
- Did you add sight-gauge/glass tubes?
- Before the saw cutting, how clean did you have to make the tank, and how did you accomplish it?
I am a diesel newbie and fear a saw-spark ignition, but not sure if that is a valid fear with this fuel?

32grand, welcome aboard. Diesel is difficult to ignite unless it is heated. I have personally stuck a lit road flare into a pan of diesel. It would not ignite. After trying for a while to get it to ignite we finally added about an ounce of gas. It lit with a match. After it had burned a bit and was put out, diesel was then hot, the diesel would ignite easily with the flare.

From having cut up a home heating oil tank. The sparks from a grinder or cutoff wheel will ignite diesel. But without atomization diesel will not explode like gas.
I have cut into several tanks that could no be emptied completely, I drilled a hole into the tank, and then using a metal cutting blade on a sawzall to open a window big enough to service the tank. After thorough cleaning, the tanks were repaired with welding, painted inside with tank liner, and welded shut. I used this process to repair the keel and saddle tanks in my steal sailboat.
By the way, If you keep the blade speed down, a sawzall blade will cut a long way through steel. Run the saw at about 1/3 of it's full RPM. My personal record is almost 4 feet through 1/4" plate before the blade needed to be replaced. Run the saw at full speed and you will only get a few inches. You want a blade with a tooth spacing that will allow 2 teeth in the thickness of the steel of possible. If not, the finest you can get.

Fuel tank replacement

SelahWay said:

We have an 1980 36' Albin with steel fuel tanks that will need to be replaced soon. A thought come to me today that I could use the two stainless steel water tanks in the lazerette as the fuel tanks. I could then cut out the existing fuel tanks and use those spaces for bladder water
tanks. Has anyone done similar? Is it doable?

Click to expand...

I have a 1984 GB 36. The old tanks were taken out and two new aluminum tanks were installed. The measurements of those thanks are such that they fit through the cabin door if they have to be taken out and replaced. Just a thought.