Floor replacement clearance

[1bountyhunter]

I'm in the process of replacing the floor in my 1980 Thundercraft Citation that I just got. I noticed that the bottom of the plywood (what's left of it) is not touching/sitting on the 2 stringers, is this normal? I've never replaced a floor in a boat, but attempting too. There seems to be a good 3/8" - 1/2" clearance between the bottom of the plywood and the top of the stringer. It has no center support, because it has some kind of removable "Teak Deck" and when you remove it you can see the bottom of the boat. I have posted a question on another post "Center Floor" that has a photo of it. I'm not sure what it's for, I know it's not a holding tank.
Any and all help on replacing the floor or what the center piece is would greatly be appreciated.
Thanks