The O'day 28 was a completely different boat from the 280. The 28 was earlier models built for the O'day yacht
line and was much wider,heavier, and better sailing boat. The 280 was basically a 272 hull with a new deck and interior. It was a really dog of a boat. It was one of the last models that O'day built and helped put O''day out of business. I also don,t believe that any of the O'day 28s were manufactured with 1 cylinder engines although some of the early ones had OMC saildrives.