Oh Boy...This Smell Ain't Good

[scofflaw]

There is no issue with an aluminum tank getting wet, because as you noted, water will still get in. In order to prevent moisture from laying against the tank there must be allowable air flow around the entire tank.

Yes there are 3 drain holes in the coffin aft.

Re: "Poly tank is a much simpler install as well"....

Not in my case. Securing the tank, poly or aluminum, would pose the same issues I'm battling.

When you seal up that coffin there will be no air flow, 100% humidity at best.

Poly tank way simple.. Foamed the 4 corners and in the middle as well. The Moeller tank straps are pure junk, the have a plastic coating that falls off after a couple of years and the strap begins to rust.

[Jason2tpa]

I'm probably mis-reading but I still don't see why you can't epoxy 4 blocks (filler blocks) that fit in-between the stringers and tank tabs. Then screw to the blocks.

Set the tank where you want it, trim blocks to fit each corner and epoxy overnight.. You, right now, have plenty of room right now to clamp the "blocks" to the stringers...

I'd (if the epoxy would take to to it) use that plastic composite (used around the boat in either black or white colors).

Also, you may consider a smaller amount of foam (I know they make different types) at the four sides towards the ends. It'll easily last 10 years and work fine. *You had ONLY foam before and the tank didn't go anywhere. Shouldn't be an issue using the correct foam...

Re the straps, if Aquasport used them originally, were the straps attached to the deck (under the tank). Why not simply attach there?

Does the fabricator have any specific ideas that he recommends?

There is only 1/2" space on either side btwn tank and liner. I wouldn't think 1/2" of block is enough to give the screw ample security.

However, what I could do is have the fabricator weld the tabs 1/2" from flush with side of tank. Then Id have space for 1" blocks. That sounds good. I'll speak with fabricator to make sure welding tabs setback from flush is ok.

Originally, when AQ was building the hull, they of course had access to the underside of the liner before they molded it in. Straps were fastened using thru bolts with large fender washers.

[TownsendsFJR1300]

There is only 1/2" space on either side btwn tank and liner. I wouldn't think 1/2" of block is enough to give the screw ample security.

However, what I could do is have the fabricator weld the tabs 1/2" from flush with side of tank. Then Id have space for 1" blocks. That sounds good. I'll speak with fabricator to make sure welding tabs setback from flush is ok.
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That should work BUT, you may have to epoxy in the blocks AFTER the tank is set in the coffin.

Only because the blocks will/MAY be sticking out more than the tank is wide.

Really, 3/4" to 1" screws are plenty (2 on each corner)..

Thru say the 1/2" block, then just piercing the fiberglass stringers (all pilot holed).. That'd be very solid..

[Jason2tpa]

That should work BUT, you may have to epoxy in the blocks AFTER the tank is set in the coffin.

Only because the blocks will/MAY be sticking out more than the tank is wide.

Really, 3/4" to 1" screws are plenty (2 on each corner)..

Thru say the 1/2" block, then just piercing the fiberglass stringers (all pilot holed).. That'd be very solid..

Agreed. I won't be bonding anything until the new tank is in the coffin to confirm measurements.

[Jason2tpa]

When you seal up that coffin there will be no air flow, 100% humidity at best.

Fuel coffins should never be completely "sealed", as in being air/fluid tight. If this were so it would promote and enhance crevice corrosion. Impossible to prevent condensation, so it's necessary to allow evacuation of this condensation. The coffin needs to have drain holes to allow water to flow out and air to flow in and around tank.

[scofflaw]

Fuel coffins should never be completely "sealed", as in being air/fluid tight. If this were so it would promote and enhance crevice corrosion. Impossible to prevent condensation, so it's necessary to allow evacuation of this condensation. The coffin needs to have drain holes to allow water to flow out and air to flow in and around tank.

Don't think your getting my drift.. a couple of holes at the bottom of an other wise sealed unit, that will be getting wet, whether it's condensation or back flow thru those mentioned holed doesn't fit the definition of air flow. Air won't flow with openings on 1 end of a sealed cube. Just sayin,but it's your baby. Got me the same setup...always wet in there.

[Jason2tpa]

Don't think your getting my drift.. a couple of holes at the bottom of an other wise sealed unit, that will be getting wet, whether it's condensation or back flow thru those mentioned holed doesn't fit the definition of air flow. Air won't flow with openings on 1 end of a sealed cube. Just sayin,but it's your baby. Got me the same setup...always wet in there.

I catch what you're saying. The purpose of the holes are strictly to allow water to flow out.

And I agree, air does not "flow" in and out of the coffin, no matter how many holes and where they are located. Because air does not "flow" under the deck. I believe I didn't explain this and the above principles clearly in my response.

Holes in the liner provide water an escape path into the bilge, thereby preventing standing water at the bottom of the coffin. The tank should not be in contact with anything that traps water between it and the tank. This is the purpose for elevating tank off the bottom using pvc strips bonded to bottom of tank.

[99yam40]

I think most of us understand, but as usual there will be naysayers in the crowd

[Jason2tpa]

Update and Finale:

Time to put this thread to bed. New tank is installed. For those interested here are the tank prepping details:

*5200 fast cure bonded 1/4" thick x 1-1/2" width pvc board strips the length of tank, 3 strips, 2 on outer edge and 1 down middle. Heavy coat of 5200.

(prior to bonding I etched tank with 80 grit where strips would bond. Also sand blasted the bonding side of pvc strips. Cleaned both tank and strips with acetone soaked rag)

*Let cure 24hrs

*Sand blasted strips, acetone clean. Ran a 1/8" bead of 5200 fast cure down the middle of each of the 3 strips. Carefully lowered tank down into coffin. Filled the fuel tank with the 15 gallons I had siphoned out of the old tank (which was brand new fuel). The fuel in tank provides an even downward weight distribution.

*As the above cured I worked on the securing tabs. I cut (4) pieces of 3/4" thick x 3.5" width x 4" length pvc board, (2) pieces of 3/4" thick x 3.5" width x 8" length.

*Opting not to have fabricator weld tabs, the pvc board was 5200 bonded to top of tank and bonded to coffin liner. Areas of bonding to tank and pvc board was etched prior to bonding, same as previously mentioned.

All in all the install went very well, no hiccups to mention. The tank is elevated off the coffin by 1/4" strips of pvc and centered in coffin with 2" space between coffin and tank. No foam, no glassed in locking tabs, or anything on top of tank.

Essentially the tank is hovering inside the coffin, using pvc board to keep it off the bottom and away from the coffin on 5 sides . If/when water gets in the coffin it drains out via 3 thru holes located most aft that drain into bilge. Barring some unforeseen accident, this is the one and only tank I'll need to install in this boat.

[Jason2tpa]

Update and Finale:

Time to put this thread to bed. New tank is installed. For those interested here are the tank prepping details:

*5200 fast cure bonded 1/4" thick x 1-1/2" width pvc board strips the length of tank, 3 strips, 2 on outer edge and 1 down middle. Heavy coat of 5200.

(prior to bonding I etched tank with 80 grit where strips would bond. Also sand blasted the bonding side of pvc strips. Cleaned both tank and strips with acetone soaked rag)

*Let cure 24hrs

*Sand blasted strips, acetone clean. Ran a 1/8" bead of 5200 fast cure down the middle of each of the 3 strips. Carefully lowered tank down into coffin. Filled the fuel tank with the 15 gallons I had siphoned out of the old tank (which was brand new fuel). The fuel in tank provides an even downward weight distribution.

*As the above cured I worked on the securing tabs. I cut (4) pieces of 3/4" thick x 3.5" width x 4" length pvc board, (2) pieces of 3/4" thick x 3.5" width x 8" length.

*Opting not to have fabricator weld tabs, the pvc board was 5200 bonded to top of tank and bonded to coffin liner. Areas of bonding to tank and pvc board was etched prior to bonding, same as previously mentioned.

All in all the install went very well, no hiccups to mention. The tank is elevated off the coffin by 1/4" strips of pvc and centered in coffin with 2" space between coffin and tank. No foam, no glassed in locking tabs, or anything on top of tank.

Essentially the tank is hovering inside the coffin, using pvc board to keep it off the bottom and away from the coffin on 5 sides . If/when water gets in the coffin it drains out via 3 thru holes located most aft that drain into bilge. Barring some unforeseen accident, this is the one and only tank I'll need to install in this boat.

[TownsendsFJR1300]

Looks great! Filler tab dead nuts on!

How" tight" are the glued in blocks? Pretty sturdy?
(Don't think it's going anywhere)

Did you get the fuel gauge figured out?


BTW, Looks like he did a VERY NICE job on the tank...
Just curious, (if you don't mind), roughly how much for the tank?



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[Jason2tpa]

Looks great! Filler tab dead nuts on!

How" tight" are the glued in blocks? Pretty sturdy?
(Don't think it's going anywhere)

Did you get the fuel gauge figured out?


BTW, Looks like he did a VERY NICE job on the tank...
Just curious, (if you don't mind), roughly how much for the tank?



.

Thanks bud. Using the blocks in between tank and coffin frankly was just gonna be too much work. This is because the tank sides are vertical but the coffin sides angled out. Which means I would of had to angle cut the boards, yada yada.

Yeah the boards are def not going anywhere. That 5200 is no joke. But really the purpose of those 6 boards bonded to sides of tank is to just provide a little security against lateral movement. With tank also bonded to coffin floor, it ain't going anywhere.

Re: Fuel gauge. Yes. I updated that thread: http://www.yamahaoutboardparts.com/f...p-th28439.html
Take a look and let me know what your thoughts are.

I'm glad you asked me about the fabricator because I forgot to mention him in my update. He is a independent fabricator, owning his business called Sunrise Marine Tanks in Venice, FL. He (Tony) used .125" AL, 56x20x6. 29 gallons. Tank price was $355 ($12/gallon) + the WEMA sender for $35. Same WEMA sender bought at west marine is $75. Total cost was $390. He was the lowest quote from the 6 places I called. But best of all, at least for me, is his turnaround.

The other 5 tank business I got a quote from told me their turnaround was minimum 12 days. Tony started fabricating my tank on Wed. May 3rd. He called me Monday morning, May 8th, to tell me the tank was done. If he worked on the tank over the weekend it took him 5 days, if not 3 days. Very impressive. I recommend him for those of you who ever need a tank.

[TownsendsFJR1300]

That's great!

I like that everything (fittings) are back where they were before so no "jerry rigging"...

Nice too that all you had to pull was the deck plate.

[panasonic]

How is that deck hatch attached to the boat....any screws?

Have you got the hatch put back down?

[Jason2tpa]

How is that deck hatch attached to the boat....any screws?

Have you got the hatch put back down?

The upper edge of coffin sits lower than the deck. The fuel hatch simply fits right on top of the coffin edge, sinking in and becoming flush with deck. 6 screws are used to seat hatch. Sealant used to fill crevice between edges of deck and hatch. Then the console gets put back in its position, secured to deck with screws imbedded in 5200.

Yep, sealed the hatch last night.