pvc pipe runner for wiring

[RICHV]

redoing my 74 tsuami and i want to put a 3 or 4 inch pvc pipe runner for wires and steering under the floor. is there foam under the floor from the helm down to the transom or is it hollow underneath the floor. i dont want to pull up the whole floor but there are some soft spots and if i am going to restore this thing i had better do it right.can anyone tell me if it is just better to replace the whole floor now or just the soft spots and where i install the pipe. i don't mind spending the time- too many hours as of now to complain about that and the last thing i want to do is repair the floor a couple of years from now because soft spots keep developing.i believe doing it right the first time is the best way- so any input will be much appreciated.