preferred fuel tank replacement material choice

[Woodsong]

So just for fun, and the fact I may pre-emptively replace my older tanks at some point in time, let's talk fuel tank replacement options. *We've got aluminum, steel, stainless, poly, fiberglass, etc. *Instead of googling for hours I thought I'd touch base here at TF. *

If you replaced your old fuel tanks, what material did you go with for your new tanks (steel, aluminum, poly, etc.) any why did you feel it was best for your application? *What would you use if you had to do it over again knowing what you may know now? *What do you think is the best bang for the buck when it comes to fuel tank replacements? *What would you NOT use if you did it again or ever do it in the future and why?

 

[Nomad Willy]

Hi Tony,

I thought we just had this conversion but for thew record I replaced mine w the repower. I thought it would be stupid not to. I could'nt get mine out without R&Ring the engine and I think most boats are like that. The Nordic 32 is an exception w aluminum in the stern. I approached quite a few to many about tank material and expected most to say SS. Either almost all or all said to go aluminum. Monel is probably the RR of fuel tanks but I'm sure VERY expensive. Everyone seemed to think aluminum was best so I ordered Aluminum. This is one choice where I went w the crowd. If I had it to do over again I'd still go aluminum but I'd follow the yard and tank builder much closer and make sure they built it to my specs. I'd specify a tank that was unquestionably designed w slanted bottom panels so even one drop of water would immediately pass through the drain at the lowest point of the tank. Then I'd have a 1 gallon tank made that would be installed below the main tank and a pump out from the lowest point on that tank. I'd install a very small pump to pump out the sub tank so I could easily check for water and quickly pump out ALL the water in the system. There would be a small amount of water in the sub tank most of the time but it could be replaced easily and cheaply and there would NEVER be ANY water in the main tank. This would'nt cost much extra to do.

 

[FF]

The best , tho a bit pricy is always MONEL, period.Sparkman and Stephens or US Navy fill and sump design.

Today the second best choice is plastic .Smaller sizes , multiple tanks , so there empty when not in use.

Aluminum or black iron are OK as a proper marine tank with a sump and proper fill can be built ,

but both will rely on the expertise shown in their installation , and require vigilance and maint to exist.

*

With proper design water can be removed as required.


-- Edited by FF on Wednesday 1st of June 2011 04:17:37 AM

 

[Phil Fill]

Our middle tank split a side seam, so cut a hole big enough to get into the tank, and had the tank welded from the inside.* We used a small 120 volt AC welder and went real slow so tank did not get to hot.* I was surprised how good of a condition the tank was in.* So before you start cutting up your old tank, you might want to see what condition is it is in and if it can be repaired.*

When the time come I am going to open the old tank, clean it and use it as the frame work for multi smaller tanks that can fit through/in the existing engine room.** I want then to stand vertical, manifold together so only one or two tanks would be used at a time, and could be easily drain cleaned.

My first choice is plastic, second mild steel and third aluminum.* SS is not recommended for fuel as SS needs to breath as fuel get stagnant.* The reason for mild steel over aluminum is mild steel, rated 15, has a higher galvanic rating than aluminum, rated 7. Our mild steel tanks have lasted 30 years and there are many mild steel that have lasted 50+ years.* The advantage aluminum has over mild steel is its lighter and easier to weld, but they have to be installed correctly and maintained.* ***


-- Edited by Phil Fill on Wednesday 1st of June 2011 09:18:51 AM

 

[Woodsong]

Eric,
Did I already post this question previously? I will check- perhaps I am getting pre-early-senior moment here in my late 30's?? I may have as I have been pondering it for a bit I guess!!

 

[Nomad Willy]

I don't know*** ....I'm 71.

PS,* .....I think I got it from Boatdesign.net. Sorry.


-- Edited by nomadwilly on Thursday 2nd of June 2011 12:09:19 PM

 

[JohnP]

Tony,* I went with poly, happy with the results.* I reduced my tankage from 250gallons to 150gallons.**The original tanks were in pretty good shape* I discovered this as I cut them up (too late to save).* I like the idea of having tanks I can see all the way round as opposed to only seeing the inboard sides.* I also wanted tanks I could install or remove without pulling the engine.

If I were doing a bigger boat with more need for fuel storage, Knowing what I now know I would cut big inspection holes and see if the tanks could be restored.

My starboard tank was leaking from the bottom in a blind area and I would have to pull the tank to see the bottom.* I assumed the back and top were suspect but later found that they were not too bad.

I am glad I changed them and have nothing that can rust or corrode and cause a fuel leak.

JohnP


-- Edited by JohnP on Sunday 5th of June 2011 03:56:09 PM

 

[yo]

John how are the tanks working out* for you so far?* Did the new poly tanks have an baffles?* What does each new tank hold in gallons?*

 

[El Sea]

We use poly totes to transfer fuel (both gas & diesel) during our service calls. If we leave the diesel fuel in the totes for a few days we sometimes see an*alarming amount of condensation and bottom sediment develop.

*

*

 

[Nomad Willy]

I flew ultralight aircraft for 20 yrs and we used Jerry jug type plastic fuel tanks almost 100% of the time. We we were worried about condensation inside the tanks when we first started flying. I was one of the very first to do this and over 20 years I never had water in my fuel for any reason that I can recall. Of course we were using pre-mix oil and gasoline for the 2 stroke engines* ..mostly of snowmobile origin. Never any condensation. So I'm very surprised to hear you (ElSea) had a problem with it.

 

[FF]

We use poly totes to transfer fuel (both gas & diesel) during our service calls. If we leave the diesel fuel in the totes for a few days we sometimes see an alarming amount of condensation and bottom sediment develop.



Perhaps , but it could simply be IN the fuel you purchase , and simply is settling out.

 

[El Sea]

We typically do not purchase fuel, but rather pumping out of tanks being serviced. Example; we place 14.5 gallons in a 15 gallon poly barrel and with in a couple of days there is a heavy amount of condensation dripping from the underside of the inside of the barrel and at the bottom of the fuel in the barrel.

 

[sunchaser]

A good check for water in your fuel is to look for droplets on the underside of your fill caps.

 

[JohnP]

yo wrote:
John how are the tanks working out* for you so far?* Did the new poly tanks have an baffles?* What does each new tank hold in gallons?*

**********Yo,***No problem with the new tanks,* not worried about a tank letting go and finding the bilge full of diesel.** The tanks have no baffles,* so far so good, my boat rarely sees rough Seas. The fuel movement may help suspend contaminates and allow them to be filtered out.* My lehman fuel burn and return* rate is small and internal fuel movement would be nill in a baffled tank.

**********Been better if the had a 2" filler inlet instead of the 1.5"---but I can deal with the slower fill rate.

********* Overall happy with them.** JohnP

 

[yo]

JohnP * I to have poly tanks, 4* tanks,* two on each side 50 gal each. no baffles in these tanks but I am concerned about air bubbles when fuel is sloshing around, have had the engine rpms just slowly drop and then just shut down usually after 20 plus hrs.* would start right up again and run fine some times for 3 hours,or sometime 8 hours but you would never know when the engine would shut down again. Boatus put out some info about the tanks, said that the lack of baffles caused the problem. We put a electric fuel pump in line and the problem stopped. Now considering a day tank.** 120 ford lehman


-- Edited by yo on Saturday 1st of October 2011 06:08:50 PM

 

[Island Cessna]

Sounds like a vent problem. Bill

 

[Marin]

Woodsong wrote:
If you replaced your old fuel tanks, what material did you go with for your new tanks (steel, aluminum, poly, etc.) any why did you feel it was best for your application? *What would you use if you had to do it over again knowing what you may know now?

*The previous owner of our boat replaced the boat's original iron tanks with stainless tanks.* As we learned in our pre-purchase survey, stainless steel is not (or was not at the time) a material recommended by the ABYC.* The reason we were told is that there is stainless and there is stainless.* Way too many variables, not only in the quality of the material.* Just because it's called 316 for example, doesn't automatically mean it will measure up to those specs, particularly if it's from Taiwan or China.

Also, stainless changes property under high heat, like when it's welded.* So unless the welds are done EXACTLY right, and unless the stainless stock is EXACTLY what it's supposed to be, stainless tanks can be very problematical, particularly along the welds where crevice corrosion and pinholing can occur.

Stainless tanks can be very well done, of course.* But it was explained to us that the potential for less than top-notch work and materials was too great for the ABYC to recommend it as a fuel tank material.

Given the choice, I would probably go for composite tanks.* This is what Grand Banks is using in their boats today.* I have heard bad things about aluminum tanks in the past, but I think this, like the stainless issue, had to do with the variables in materials and construction rather than being a blanket condemnation of the material across the board.

 

[JohnP]

yo wrote:
JohnP * I to have poly tanks, 4* tanks,* two on each side 50 gal each. no baffles in these tanks but I am concerned about air bubbles when fuel is sloshing around, have had the engine rpms just slowly drop and then just shut down usually after 20 plus hrs.* would start right up again and run fine some times for 3 hours,or sometime 8 hours but you would never know when the engine would shut down again. Boatus put out some info about the tanks, said that the lack of baffles caused the problem. We put a electric fuel pump in line and the problem stopped. Now considering a day tank.** 120 ford lehman



-- Edited by yo on Saturday 1st of October 2011 06:08:50 PM

******** Yo,* My concern was when running with a low fuel tank (less than 1/4 fuel that this could happen)* my usable fuel amount is really reduced if this is the case.

My solution was to install a fuel transfer pump,* so I can completely emtpy one tank into the other and not risk running on a low tank.

Never really used it for this as I have not had the tanks*less than half full.

Too easy to just pull in and fuel up where we boat.

If your tanks are 50gallons each could you just use one for a day tank?** And* fill it from the others when it is half down?

JohnP

 

[Fenway Frank]

Tony,* I went with poly, happy with the results.* I reduced my tankage from 250gallons to 150gallons.**The original tanks were in pretty good shape* I discovered this as I cut them up (too late to save).* I like the idea of having tanks I can see all the way round as opposed to only seeing the inboard sides.* I also wanted tanks I could install or remove without pulling the engine.

If I were doing a bigger boat with more need for fuel storage, Knowing what I now know I would cut big inspection holes and see if the tanks could be restored.

My starboard tank was leaking from the bottom in a blind area and I would have to pull the tank to see the bottom.* I assumed the back and top were suspect but later found that they were not too bad.

I am glad I changed them and have nothing that can rust or corrode and cause a fuel leak.

JohnP


-- Edited by JohnP on Sunday 5th of June 2011 03:56:09 PM

John,
I have the same boat and suspect a corrosion problem with my 125 gal black iron starboard tank. I have corrosion at the top of the tank due to leakage around the tank fill fitting. Any idea how thick the steel is on the top? No sure how to detect the extent of corrosion since the area is difficult to see.

What dimension size tanks did you use and where did you purchase them? Do they have bottom drains? Did you customize where the fittings were located? Do you draw from the top? Was wondering if linking several smaller polytanks at the bottom of tanks would solve the baffling problem? What is your opinion? Was considering using small steel steel tanks linked together but like being able to see into tank and lightweight installation of poly.

Also, did you have to remove any engine components to install your tank?

Sorry for all the questions but since you have the same boat it helps to know what problems I can expect.
Thanks
Frank

 

[Fighterpilot]

Californian 34LRC.We replaced one of our 125 gal. tanks this past winter. The old one was leaking but not such we could find it. Weeping is probably a better guess. To avoid cutting the deck etc. we cut out the tank and replaced with two, one the largest we could get down thru the engines hatches and back thru between the engines to the tank bed and another smaller one to bring the total up to close the original total. I lookded into poly before making a decision for aluminum. Aluminum made to my specs and size with baffles. Cost was not that much difference than poly tanks and I could get the shape and size I wanted.