I believe the CS40 is similar in construction to the CS36 Merlin with some coring in the hull. I don't know if the coring us used below the water line. The ONLY CS boat I've seen in person was a 36 Merlin that had seen its better days. I wish there were more around locally, because I think it would be an impressive boat if you found a well kept example.
s/v Palmetto Moon
1991 Catalina 36