This is something I have been considering as well but for a different purpose.
I am currently in the process of replacing the cabin sole
on my Sabre
36 because the subfloor was not sealed and (a common issue on these boats) the limber hole for the mast step would clog. The next place for the water
to go is into the floor.
An opening like the would allow me to clean out the limber hole. anyone out there done this?