Any Core Material in 21SE Hull Bottom?

[fishinSWFL]

I am thinking about mounting my Airmar transducer shoot thru style in the bilge of my 21 SE. It is a thru hull type ducer but I don't want to cut another hole in the boat.
I am wondering if I can just glue it in at the lowest point in the bilge or if there is some core material that needs to be cut away first?

 

[Bryan 2530]

no core.

Try searching, this has been covered in detail in the past.