Polyethylene gas tanks vs aluminum

[jdupree]

Has anyone had any experience with the polyethylene gas tanks from Boaters World, West Marine, etc.  Trying to decide whether to go back with aluminum again for my CCP or try the polyethylene tanks.  Just wanted some opinions and here is one like I am talking about.  Thanks,
http://www.boatersworld.com/product/357980135.htm

[Ben87]

Here is what I know as I'm into a new build right now.  I inquired about aluminum versus the poly tanks and even having an aluminum tank coal-tar/epoxied as one guy I spoke with had it done and the builder said that Poly tanks are recommended for the E-10 fuel and that the vast majority of fuel tanks in cars/trucks are now poly, I was under my 2004 Tundra and sure enough what is under there? a 26.4 galoon poly tank.  So I'm having 2 60 gallon poly tanks installed.

I don't have any direct experience with the tanks from BW/WM though.

Here is a shot of one of the 60 gallon tanks that has been put into the boat I'm having built.  You can see the forward tank on the right.  I don't know the maker, they could be custom tanks for this boatmaker for all I know.  

[Irish Rover]

A friend of mine has been using a tempo 29 gallon for abut two years now, says it works great.  The thing that surprised him was how much those tanks can expand with heat, like 1/2 and inch.  And the bigger tanks apparently can expand upwards of an inch.

If I had to replace my tank I would go poly.

Just my two sense

Justin

[jdupree]

Thanks for the opinions :) I have already made up my mind.  I plan to go with poly.  Hopefully can get my old tank out this weekend so I can get some measurements for the new tank.  I plan to go with around a 50 gallon tank.  I was hoping to find one with the sending unit in the middle of the tank, so I would not have to cut another access hole.  Besides Boater's World, West Marine, etc does anyone know who else would have a good selection of the poly tanks?

[JimCt]

Am looking at poly too.  Be interested to hear what you come up with.

[LilRichard]

Just wondering why everyone is interested in Poly?  I have read about both, but was concerned about the expansion contraction issue, along with finding a tank to fit my exact dimensions.  Is there a reason everyone is steering clear of Aluminum?

[JimCt]

E10 fuel is why I'm looking.  No history on how aluminum tanks will behave over time with the alcohol additive.  Expansion/contraction is the down side of poly but properly sized & secured this shouldn't be a problem.

[jdupree]

Just wondering why everyone is interested in Poly?  I have read about both, but was concerned about the expansion contraction issue, along with finding a tank to fit my exact dimensions.  Is there a reason everyone is steering clear of Aluminum?

I agree about finding a tank to fit the dimensions that I need, but if I can find something close I can make it work.  The expansion doesn't concern me too much.  I will just take that into consideration when measuring for the new tank.  I think cost is something else to take into consideration to.  Unless I am looking in the wrong places, I can get the same size poly tank for a minimum $200.00 less than aluminum tank.  Never have to worry about much condensation and no corrosion :)

[LilRichard]

What pricing are you looking at for both? For me, I only found about a $100 difference.  

I just went to google for 2 minutes and found this... could be bogus, but:

"From the corrosion standpoint, aluminum can have some issues when you get into 85 percent ethanol," said Mike Bartush, product manager, environmental systems for Cincinnati-headquartered OPW. "We offer an anodize product that coats these materials so that there's not a problem with these alternative fuels. We also changed some of our gaskets about five years ago to be more compatible with the new fuels. When you're talking about five or 10 percent ethanol it's not an issue with our aluminum tubes and aluminum adapters. And it's not an issue with our cast-iron shear valves and steel piping and brass. We take all the different fuels and we soak our products in them and test them."

http://www.ethanolmt.org/switch.html

I just get iffy with a plastic fuel tank over a 20 year span.  Yes, aluminum might corrode if not installed properly, but plastic has a fatigue life to it also.  I don't really have an opinion either way, just trying to play devil's advocate.

[Ben87]

I for sure don't know a heck of a lot when it comes down to it but wouldn't the expansion/contraction not really be an issue as the tank would be vented much like a car/truck and how aluminum/poly boat fuel tanks are anyway?

[rsh19904]

Well, lets put it this way..alum tank:  has to be coated to not have any issues, poly, just put it in and go..

alum, not much expansion, poly; can expand alot if not vented. (outboard tanks with air valves shut good example, they look like a baloon)  but think ben's right, since the poly will be vented to the outside there should be no need for the tank to expand nearly as much as it could because there's always an open vent..

you can also have custom poly tanks made and i saw on the perko website and boaters world where the tanks have the v shape in them, with or without sending units..in hull, side gunnell and above deck units too..so basically whatever you want....and hopefully no bad welds   ..but its really all about preference and what someone is used to..kinda like what type of motor you run..they all move the boat its just what you like..