Today I bought a mushroom Apollo through hull fitting, part number 65-BN7-63 and an Apollo valve part number 78-256-10. I think the valve is and NPT thread but I cannot find on the web wether the through hull is a tapered thread or not. I bought these at West Marine. These parts are 1/2 in and are replacing the glassed in nipples that Catalina put in their early C27's. I will check with West marine but they usually look up the infor in the book and if it's not there they won't know. Anyone know of a source to find out what these are?