Fuel tank coffin holes/install questions

[Aaron43]

The coffin box for my 85 gallon aluminum fuel tank has 6 holes in it. The holes are about 1 inch in diameter. There are 4  holes located near each corner of the coffin and 2 holes centered, all on the outside walls. I am wondering if it would be wise to fill the holes in the coffin in order to keep water in the bilge off from the fuel tank...I assume the holes are there for a couple of reasons, to put the tie down straps thru and to allow water to drain out of the coffin box. I plan to seal the cover over the tank with 4200 to prevent water intrusion. I plan to place the tank on plastic strips screwed and sealed to the coffin box floor...to secure the tank I am considering notching out the plastic strips to accommodate the hold down straps.

Any one have a better idea, an easier or better way?

Are the holes in the coffin box even worth bothering with....

What did Aquasport use to "pad" the tanks?

[Capt. Bob]

First and foremost, you want the tank coffin, therefore the tank itself as dry as possible. Unless you plan to use the existing holes for attachment, then I would recommend you seal them.

Second, keep the tank off the floor. This allows some air to circulate (not much really) but also keeps the exposed aluminum separated from moisture trapped between it and the coffin bottom. Sounds like you're on top of this.

Seal the hatch both seam, mounting screws and deck plate(s) as best as you can.   
Sounds like you got that working also.

So... There are many tank installs in both this forum and different rebuild forums. Members install several different ways, mounting, coating, not coating, foam or no foam. If you haven't already, spend a little time digging through the threads in this forum. Properly done, one works just as well as the other as long as your final objective is keeping the tank dry. You can't physically prevent condensation but it's the least of your concerns if you have followed the other procedures carefully.

Here's a few to get you started:
http://classicaquasport.com/smf/index.php?topic=2597.0

http://classicaquasport.com/smf/index.php?topic=4360.0

http://classicaquasport.com/smf/index.php?topic=1854.0
The last one has two links worth review including the Pascoe method.


PS.... OEM in your era Aqua was foam pad under the straps. The corrosive kiss of death to a countless number of tanks.

Good luck.

[Aaron43]

Thx Bob...glad you are here, you are on top of things and very willing to help...rare, it seems, these days. Thanks again. I noticed the coffins in those pics had no holes in them....I just assumed the holes were factory....