Love my Mako but

[3 boat guy]

I restored this 1973 20ft Mako completely last season but my passenger pedistal seat is loose and starting to crack the floor. Hesitant to un bolt it to take a look at fastners ( don't want to loose nuts!) any insight appreciated.

IMO, it is loose because there is a rotten plywood backing plate or the (cored?) deck has rot. There is a fuel tank access under the console? Either that way or cut a hole in the fish box just aft of the pedistal (easier to repair than deck).

[3 boat guy]

i removed the console and replaced the fuel cell last year ,I think the fish box access is a great idea Thanks you