Well I know how thick the 1966 vintage Cortland-built Chris Craft Sea Skiff fiberglass hull is on the bottom. I installed a high speed flush mounted depth sounder transducer today, and the darn hull is a full 1/2" thick. I'll post a photo of the plug I took out; green gel coat on the bottom, gray bilge paint on the top.
I’ll bet there aren’t too many new boats this size being built today that have this amount of high quality polyester and fiberglass on the bottom. Chris Craft went out of their way to be sure they used high quality resins, and THIS sure drives the point home. It is the same material used on the Commanders (as clearly stated in Chris Craft literature of the period).