Tempest (NOT International TEMPEST, that was a racing boat) was built from about 1965-1970. The O'DAY 23 (like yours) was built from 1971-74. There was also a newer O'DAY 23 built from 1977-85. The TEMPEST was a Philip Rhodes design with a large cockpit and small cabin (2-berths), cast-iron fixed keel with an inboard rudder.
The O'DAY 23 (1971-74) was more of a cruiser, with 4-5 berths, a cast-iron shoal keel with a retractable, fiberglass centerboard housed inside, and an outboard rudder. This boat was offered in 2 versions at first, one looked like a slightly larger O'DAY 22 and the other had same hull but a larger cabin trunk that could be lifted like a pop-up camper for more headroom. Later (1973-4) the pop-top version was changed to look like the standard cabin model but with the ability to lift the aft half of the cabin roof (instead of whole cabin trunk).
The later 23 (1977-85) had a shoal-keel (with centerboard) that was molded as part of the hull with lead ballast inside keel molding.