Fiberglass under typhoon teak tiller plate!

[Lotis]

I am currently pulling all the teak off the Lotis to sand down and varnish and although the fiberglass under the teak plate beneath the tiller is solid as a rock i wondered if someone had a picture or could describe what it is supposed to look like under there. Mine has a rectangular hole maybe three inches by four inches which the rudder post runs through. Just wondered if this is how it was made as water sloshing up through the rudder tube would run straight to the bilge with this arrangement. Any help would be much appreciated!