I am intending to install an HF radio on my Catalina 36 (1985). I want to place the transmitter box just forward of the Nav station in the storage space behind the seat(it connects to a control module that I will put on the shelf above the power distribution panel. But, I need to use 3" wide copper sheet to establish an RF ground to both the keel and the auxilliary. I was surprised when I took up the saloon floor to find no way to bring the copper down the hull to the bildge. There are some depressions in the fiberglass floor with openings into the bildge. Can I drill a hole on the outbord side to gain access? Thanks Wayne