GS44MC Pump room Floor thickness

[GMB]

I am preparing to anchor battery boxes in the pump room of our GS44MC. What I REALLY don't want to do is drill into the top of the fuel tank. The boat is 180 miles away so I'm seeking those with applicable experience. How have others anchored their house battery bank in this area?
I will have four L16Es in a 2x2 configuration to provide 700 AH capacity at 12V. That is 468 lbs of Battery.

 

[Comodave]

How about using epoxy to glue some cleats down around the battery boxes and screw to the cleats or through bolt to the cleats using a T nut on the bottom of the cleat before glueing it down?

 

[GMB]

About 2 inches.

Answering for others (maybe). On our GS44MC there appears to be a 2x2 frame and 1/2" plywood over the fuel tank top that makes up the pump room floor.
This can be readily seen by opening the drop in hatch between the engine room and the pump room.