Newbie with fuel tank replacement question

[seabob4]

Exactly. The water didn't come thru the hatch.

Its encapsulated water, held in the coffin. No way to relieve itself. So while you're running...the tank is surrounded and beat with the nasty as pictured.

SB, I don't see a tremendous amount of difference between the methods. Both stress a dry top and side. Factory spec as you've described says go with metal longitudinal bands on top fore to aft.... Could those "bands" just as easily be a non-electrolysis conductor...like 2 X 1 cedar/fir/cypress dressed stock?

In reality, the "slots" molded into the roto-molded tanks in the 225 Osprey/Explorers were made to fit 2 bys...

[Circle Hooked]

Not to de-rail to much but with the concern of corosion would a poly tank be better than aluminum,any thoughts ?

[gran398]

Absolutely...a poly tank eliminates previous discussion. But for how long...and under what conditions?

A friend of mine tonight bought a 2011 brand new Carolina Skiff 21 DLV...20K with a 115 4 stroke Suzi, and aluminum single axle trailer.

Wasn't impressed...28 gallon sit-above plastic/poly tank at the stern (no capacity)...heavy print-through on the interior glass   (poor finish). Then a formed casting deck (part) forward ...was pretty...but clashed with the spackle-coat interior. And plenty of cheap components...the Attwood fuel-fill cap snapped in his hands....brand-new.

Fuel weight in the butt, where least needed. Given that, should have come standard with nice Bennett's to get the bow down. But no tabs.

Gimme an old Aquasport to rebuild.

[Woodinator]

Good info and opinions guys.  The three dominant principles I've gleaned:  1) minimize areas for moisture to become trapped, 2) maintain air flow/circulation to let the coffin breathe, and 3) keep it from shifting.  

Leaning towards a "less is more" approach.  Since the tank and coffin have no keel and are simple rectangles, I think I'm going to try and just set the new tank on two to four half-round longitudinal plastic runners attached to the floor of the coffin and cushioned by 5200, then add 4 small plastic chocks along the top edges of the tank just to protect it from the straps (attached to the aluminum and cushioned w/5200), and then just re-tighten the original straps if they're salvageable. Will result in minimal surface area making contact with the aluminum, but should still hold the tank in place, support it adequately, and will definitely breathe well.  Once I see how much space the tank has in the coffin I may add some kind of bracing or spacers (perhaps some 45 degree pieces cut to fit the bottom corners of the coffin, kind of like cooler blocks for the deck of a boat?) to further prevent any lateral shifting in case the straps aren't enough .  I have to be careful not to raise the tank too much though b/c there's already minimal clearance between the fill and vent spouts and the deck hatch.  Anybody see any glaring No-No's in the general approach?

SB-I'd definitely consider the neoprene thing as well but I don't know where to find it.

Only reason I've sort of disregarded Poly is b/c they're primarily pre-fab and nobody seems to make any in dimensions that will fit my coffin properly without signficantly costing me capacity...so aluminum it will be!  I did a lot of shopping trying to find a poly option since this is the SECOND aluminum tank of mine that became swiss cheese (two different boats).  Last time I gave away the boat entirely b/c it had already been rebuilt (poorly) once, and the gas tank was permanently glassed under the deck. Didn't feel like tackling such a project when I found a 7 year newer replacement hull in MUCH better original condition for only $1K.  

[gran398]

Good plan Ry!

Around here we have a couple of shops that make rubber gaskets etc. for local industrial use. They carry neoprene in many different thicknesses. Let me know if you want some, will send it up

[Woodinator]

Just got off the phone with Marine Connection Distributors.  They don't have a single alum or poly tank in stock that will fit this boat...out of the hundreds in stock...and that's even if I consider downsizing by a few gallons.  I guess it's gonna have to be the $300 custom.  Thank god the fabricator is less than a mile from my house so I don't have to pay gas mileage too!

While I'm at it, here's before and after for her future powerplant, plus an overall for perspective.



When I bought it...


when I opened her up...


finished and ready to reinstall!!!

[Blue Agave]

Thanks C-

Blue - when you set up your avatar, did the link say that the avatar function is currently disabled?...or is that a new problem?

The avatar function is disabled.  If you want photos add the photobucket link to your signature, just make sure and resize them to something like 200x100.

As far as your fuel tank I'd also say no foam.  When I replaced my tank I used some 3M spary glue to glue old fuel hose down on the sub floor and placed the tank down on the fuel hose.  Then I made a bulkhead with weep holes on each bottom corner and bonded it right up against the back of the tank so it would not move.  It's been in place ten years now and no problems.   I replaced the console last year and while I had the console out, I decide to inspect the fuel tank.  Wasn't sure what I was going to find, but I was happy to see that the tank was in perfect shape.  I put a new wema fuel sender in the tank and closed the fuel cell back up.