adding a cocktail table - what is under the floor
 

I have a 2001 25 shabah (bowrider) I want to add a removable cocktail table in the back. The problem is I don't know what is under the floor (about a foot in front of the back seating area). I am thinking something like this

Garelick/Eez-In 75640:01 Table Pedestal (just highlight and search on it)

These attach with something like a molly expansion bolt. My concern is how well they can handle stress. Sure as heck somebody leans on on the table and pulls up the floor.

If there would be room I could go with something like this

Garelick 2.875" Flush-Mount Taper Socket Base.

With the larger hole I could slip a lager reinforcement piece through the hole and really make it robust. When is doubt go stout.

I don't want to be cutting holes unless I have a real good idea what is under the floor. Like I said this would be about a 12 - 18 inches up from the back seat and at the center line. What is
under there? Stringers? Gas tank? Jimmy Hoffa?

Any other ideas, products or approaches would be appreciated. Any body have the actual plans?

Thanks