Flex in Glass in Gas Tank Compartment -91'-24' Offshore

[Jbird]

I installed my new gas tanks over the weekend. As I was putting the final screws in the last one, I noticed an area in the adjacent wall, that had some flex in the glass. I have no soft spots in the floor, everything has always appeared to be solid. The single area is about 12" wide, maybe 8" high. When I say flex, I can push it slightly with my hand, and some hard presssure. It looks like it is in and area where the glass is a little thicker, maybe where sheets were overlapped. Above the 8" line, its solid as a rock, no flex, and the toe nail screws locked in till the driver wouldn't turn anymore. Forward and behind this area, theres no flex at all; and the glass appears to not be as thick. This is consilidated to just this one area. I pulled the tank back out today to ensure that it only existed in this one spot and it does. Can it be typical for the glass to flex a little in a single spot, and still have a solid stringer behind it? I "think" I attached a photo of the area. Any thoughts appreciated. Thanks.

 

[onoahimahi]

I think I'd be temped to probe the area by drilling a few small holes and seeing what you find.

 

[Jbird]

Thanks. How small of a hole would I drill, and what's the best thing to use to plug it afterwards? Thanks.

 

[Jbird]

Bit the bullet; went ahead and drilled some holes. Result - no water came out, just the dust from going through the glass and wood shavings from the drill bit; there was nothing out of the ordinary; tank is back in.... Plan to seal them back up with some 5200 and consider it done. Complete overhaul of fuel system, 95% complete; just got started on redoing the electrical last weekend - what a freaking birds nest! Thanks again for the suggestions, now at least I have a piece of mind. :bang

 

[onoahimahi]

If the wood shavings were dry you should be good to go. Sometimes mud comes out...