Fuel tanks

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8AlfaActual73

Member
Joined
Nov 25, 2024
Messages
18
Location
Pensacola, Florida
Good evening, gentlemen. I have a quick question as far as replacing fuel tanks if necessary On a 1978 40' marine trader. What are the Most economical options if I do need to Replace the fuel tax and when I say economical. I mean cheapest. I've done a little research on options but I need to hear from people with experience. And the research that i've looked at are the options that i've come up with is either fuel bladder or A bank of twenty five gallons of fifty gallon polyethylene fuel thanks. Advice, guidance and opinions are greatly appreciated. Thank you.

8alpha out.
 
There are a lot of variables, how much fuel capacity are you looking for? I would not consider a bladder. You would have to have something to contain it, then there can be issues with leakage or chaffing. Dual engines or single. We need more information to give good informed answers. I could say several poly tanks would be the cheapest, but there may be better answers.
 
When I replaced mine I measured what was the biggest tank I could get through the door down the hatch and around the engines onto the flat platforms I built. I went with two 37 gallon plastic tanks. That gives me four days of cruising. I replaced all the fuel lines and installed a Groco six port fuel selector valve to switch between tanks. I still have room to add two more tanks if I want.
 
I had black iron tanks in a boat a few years back that started to leak at the bottom corner of the tank. I hired a tank guy to come out and for $2000, he cut access ports in the tank, cleaned them out extensively, then coated them with an aviation type sealer that wasn't affected by fuel. It was the cheapest way to go and the tanks were still fine after 5 years when I moved onto my next boat.
 
I had black iron tanks in a boat a few years back that started to leak at the bottom corner of the tank. I hired a tank guy to come out and for $2000, he cut access ports in the tank, cleaned them out extensively, then coated them with an aviation type sealer that wasn't affected by fuel. It was the cheapest way to go and the tanks were still fine after 5 years when I moved onto my next boat.
This is what I would look into first if I needed to on our next boat only one tank weeped at the bottom but the tank that didn’t leak fuel would have had to been patched at the top because it was completely rusted out and compromised around the fill neck.
 
There are a lot of variables, how much fuel capacity are you looking for? I would not consider a bladder. You would have to have something to contain it, then there can be issues with leakage or chaffing. Dual engines or single. We need more information to give good informed answers. I could say several poly tanks would be the cheapest, but there may be better answers.
Hi comodave,
I apologize, you're absolutely right. You need more information and it's a single single engine nineteen seventy eight forty foot marine trader.
 
Well, that should really help make the tank replacement much easier. You should probably be able to get the old tak out and the new one in without removing the engine. Are you handy? If you are then that would make it DIY and save a lot of costs.
 
What's your goal with the boat? If you're looking to create equity, removing the engine makes restoring the engine room. If your just looking for ultra cheap and don't want to pull the engine, cut out the tanks and find plastic tanks that will fit in the cavity. There are tank builders who have hundreds of different sized tanks.

Peter
 
Get a quote from a boatyard that really does this work. (good luck finding one these days)
A real boatyard has the manpower, equipment and know how to pull your engine and your tanks in one morning. They will send your tanks to a tank builder to be built in the exact same size but of better (thicker) materials. Takes about a week. During that week someone is cleaning your engine room, painting it, replacing all fuel related hoses. This is a good time to get other work done in the engine room. (shaft log, shaft, stuffing box, cutlass bearing, transmission work) The tanks arrive and are installed. The engine is installed. Everything is hooked up and tested. Sea trial with the shop foreman.
In 1995 this type of service could be had for $8,000. It still brings a smile every time I lower myself into the engine room.
 
Changed both tanks in my 45' jefferson . Gave diesel to friends for labor with install . Degassed tanks ,cutup with saws-all and many blades . Measured tank end and had to reduce size 1 " all around to fit thru window . Disconnected engine /trans , Used A-frame in salon with beefed up floor to lift engine ,slid it over other engine , hanging, while tank came in thru window , thru floor hatch . installed tank outboard of engine mounts . and reset engine/trans . Only lost 50 gallon per tank by reducing dimensions.
 
I had black iron tanks in a boat a few years back that started to leak at the bottom corner of the tank. I hired a tank guy to come out and for $2000, he cut access ports in the tank, cleaned them out extensively, then coated them with an aviation type sealer that wasn't affected by fuel. It was the cheapest way to go and the tanks were still fine after 5 years when I moved onto my next boat.
This is what I did as well. $2K, took half a day, inspection ports now installed and they blasted out the goop, disposed it at the hazmat sight, coated the tank with aviation sealant. I waited a day to refill.

There are alternatives, but I haven't heard of one that makes any sense given how fast and inexpensive recoating is. If the alternatives were better, they would cut the wing tanks off of airplanes and replace them with cobbled-together plastic aftermarket wings.
 
What's your goal with the boat? If you're looking to create equity, removing the engine makes restoring the engine room. If your just looking for ultra cheap and don't want to pull the engine, cut out the tanks and find plastic tanks that will fit in the cavity. There are tank builders who have hundreds of different sized tanks.

Peter
Hi pete,

As of Right now, my goal with the boat is to Get it running and, in the water.
 
Well, that should really help make the tank replacement much easier. You should probably be able to get the old tak out and the new one in without removing the engine. Are you handy? If you are then that would make it DIY and save a lot of costs.
Hi Comodave,
Yes, I am handy and I am Looking to cut costs however, Somethings you just can't, and I'm just trying to stay ahead of Any problems that may arise cause? I know there's gonna be. Also, thank you so much for your guidance and your wealth of knowledge.
 
Get a quote from a boatyard that really does this work. (good luck finding one these days)
A real boatyard has the manpower, equipment and know how to pull your engine and your tanks in one morning. They will send your tanks to a tank builder to be built in the exact same size but of better (thicker) materials. Takes about a week. During that week someone is cleaning your engine room, painting it, replacing all fuel related hoses. This is a good time to get other work done in the engine room. (shaft log, shaft, stuffing box, cutlass bearing, transmission work) The tanks arrive and are installed. The engine is installed. Everything is hooked up and tested. Sea trial with the shop foreman.
In 1995 this type of service could be had for $8,000. It still brings a smile every time I lower myself into the engine room.
I guess those were the days. A project like that now would take 2 months and cost $30-$50k
 
I have a 1978 40' Marine Trader with a single engine as well. I replaced my steel tanks with 4 plastic 50 gallon tanks after cutting out the old tanks and building platforms for them to sit on. I also have a 28 gallon day tank that I transfer the fuel from the larger tanks and it feeds the engine. I probably have $3,000 invested with the tanks and fitting
 
I had black iron tanks in a boat a few years back that started to leak at the bottom corner of the tank. I hired a tank guy to come out and for $2000, he cut access ports in the tank, cleaned them out extensively, then coated them with an aviation type sealer that wasn't affected by fuel. It was the cheapest way to go and the tanks were still fine after 5 years when I moved onto my next boat.
What a great idea. Thank you.
 
I’m not sure where you’re located, but I just had Petro Clean in WA clean and repair my tanks. 6 150-250 gallon tanks. 2 required an epoxy coating like mentioned above, 2 just some epoxy putty at the tank seam and 2 were fine. They pull and store your fuel while they do the work. I found their pricing to be very reasonable compared to the cost of pulling my engine and generator to enable pulling and replacing the tanks. Total cost was less than 1/2 of what new tanks w/o labor would have cost.
 
I’m not sure where you’re located, but I just had Petro Clean in WA clean and repair my tanks. 6 150-250 gallon tanks. 2 required an epoxy coating like mentioned above, 2 just some epoxy putty at the tank seam and 2 were fine. They pull and store your fuel while they do the work. I found their pricing to be very reasonable compared to the cost of pulling my engine and generator to enable pulling and replacing the tanks. Total cost was less than 1/2 of what new tanks w/o labor would have cost.
How do they deal with the baffling in the tanks? Is there an inspection port strategically placed in between each baffle? I've been trying to figure out how to get in and clean/polish each of my 150 gallon tanks.
 
Most larger fuel tanks will have baffles and therefore require an inspection port in each chamber. If you are cleaning an aluminum tank don’t use metal tools to scrape it out, they can leave very small particles of the metal on the aluminum and promote corrosion.
 
One more reason to make me love my three integrated FG fuel tanks holding 650 gallons. For a 34.5 foot boat, that is plenty and a major headache I will not have to contend with. Aside from eliminating tank corrosion/replacement issues, it provides a certain double hull safety with regards to a hull breach.
4 bulkheads in bilge creating five mostly watertight compartments is a double edged sword. It makes the boat much harder to sink, but on the other hand, makes bilge pump systems more complex than on most Trawlers, however much more built in redundancy. No pump under chain locker, but FG is so thick there, then one under V Berth area, two in engine room, two under salon/galley area, then two under aft cockpit. All requiring separate wiring, alarms and exit plumbing.
 
How do they deal with the baffling in the tanks? Is there an inspection port strategically placed in between each baffle? I've been trying to figure out how to get in and clean/polish each of my 150 gallon tanks.
I have 2 inspection ports in each tank. My tanks slope down towards the keel, so all the corrosion I experienced is easily accessible from inside the engine room. Each tank is baffled into quadrants but the baffles don’t go all the way to the top of the tank so they were able to clean the whole tank and address the needed areas.
In speaking with them, they have done tanks where the literally climb inside and remove baffles to address areas. Obviously, that requires a bigger inspection port. I recommend talking with them, or if you’re not in the PNW, they do sell the ports too. (Several sizes available).
 
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