18 Poly-Plastic Gas Tank Options ?

[silverghost]

Does anyone know of a Poly-Plastic gas-tank that will fit in an early Donzi 18.
Will the late model Donzi 18 Poly tank fit the early 18s ?
Who built these poly tanks?
Is there a model cat # ?
I need to replace the old rusty steel tank in my "Bnchseat" 18 project.
My boat is used 90% of the time in salt water. I know you can have a new aluminum tank built but i would rather go with Poly because of the salt bilge water.
Bcause of the now longer front deck of my now 37" long short aft benchseat cockpit & the weight-shift aft I can now use a much longer & higher & much bigger tank than the stock units.
I have no problem cutting-out the front floor deck.
I can fit a very big tank up there now!
Does the gas-tank really have to sit this low in the bilge/ stringer area ?
Does anyone know of a generic poly plastic tank that might work?
I know the standard 18 tank is a very strange tapered fore & aft V shape.
Anyone know it's dimensions?
Does anyone know of any Marine Surplus Liquidators that carry a big assortment of surplus poly bilge-belly tanks left over from boatbuilders ?
I have seen these on eBay from tme to time.
Since I now have this very small cockpit I can possibly have many more bigger tank options than most standard 18s.
All ideas appreciated !

[gcarter]

The problem w/generic tanks is the typical deadrise is only about 12-15* so they don't fit very well and you lose a lot of potential capacity.
Surplus Unlimited in Daytona carries a large number of tanks in stock and can probably supply something close in size.

Not the route I'd go, but there you are.....

[Walt. H.]

Poly tanks leach fumes which is something you don't want below decks, my vote would be to go with an "aluminum replacement tank".:yes:

And don't foam it in.
Opps did I just say that, now thats a topic worse then politics..:nilly: :popcorn:

[MOP]

Hey ya old fart I disagree on both! So take that:popcorn:

[silverghost]

My big Ski Boat which is a 1988, came with a 47 gallon cross-linked poly plastic "Fuel Cell".
This tank is 3/8" thick !
It sits on top of the bilge water and is as good as the day it was installed !
The bottom is completly supported & strapped-down with SS straps & rubber.
The only two Issues I had with it was ~
1)The cork gauge sender gasket dried-out and leaked fumes.
New quality gasket fixed this problem.
2) The fuel pick-up tube elbow & screw-in 1/2" reducing bushing was made of some sort of crappy aluminum and went to a pile of corroded dust.
I replaced both with high-quality brass weatherhead fuel fittings & new copper pick-up tube and no more issues there.
I like the poly tanks.
We had a 1963 Lyman with a Monel Metal fuel tank. Another friend has a 1929 75' ELCO flat deck yacht with six Monel fuel & water tanks.
These monel tanks were super~
Almost Nothing hurts Monel.
But- You just don't see Monel used anymore !
There is a large gothic cathedral in my area with a complete Monel Metal roof ! This is irreplacable today
This would cost much more than copper or SS today!

[MOP]

Tough to beat teh poly tanks, damn near -0- failure rate!

[Walt. H.]

Phil,

Most do Moeller is one company that claims not to leach, but i'd spend the extra money for a quality marine grade aluminum tank that can take a pounding and will out last both of our remaining lifetime combined.

Of course if its going into a old Bayliner then one of those oil-can type flexing plexi plastic tanks will do just fine. LOL!

Please pass the salt & hot butter..:wink:

[gcarter]

The only reason the old tanks corroded was because of the drain pipe running under the tank. The ends of the 3/4" PVC pipe running through the fwd and aft tank blkhd's was installed using double sided rubber tape.
They leaked!
Instead, run a 1 3/8" hole saw through both blkhd's and install a new piece of 1" PVC using epoxy.......
Problem solved and there'll no longer be any leaks!
The new aluminum tank will last more than your lifetime.