and such used on O'Day boats are not O'Day-specific and can be found at your local marine supply store, or order online from a catalog. Some of the larger suppliers are West Marine , Boater's World and Defender.
For parts that are specific to O'Day boats, the best source is Rudy Nickerson at D & R Marine. Rudy was the materials manager for O'Day before they, like a number of sailboat manufacturers, went bankrupt in the late 80's/early 90's. Rudy is a storehouse of knowledge about O'Days and can most likely hook you up with the parts you need. The website is www.drmarine.com -- you might want to give Rudy a call on the phone, it has been reported to work better than e-mail.
Full disclosure: this website is an internet affiliate of West Marine and Boater's World, and as such, earns referral fees if you click-through to their site and make purchases. We have no relationship with Defender or D & R Marine other than as a satisfied customer.
You may want to check out some other sources for boat parts that have come to my attention (see below). If you have some good sources, send them to me for inclusion on the list: