Tender sailer
I have noticed the same thing about my 23: she is a tender sailer, and will heel quite a bit, especially in comparison to a full keel boat like a Columbia.Any boat can be knocked down, especially when hit with an unexpected gust of wind, and I am sure that the 23 is no exception. However, I have sailed my boat to about a 30 degree heel in strong winds (25+) and lived to tell. That being said, I manage to keep the boat on its feet by reefing early and adjusting the sheets to spill a little wind. Just keep in mind that this is not a boat designed for comfort in heavy weather. As I am sure you have already discovered, the O'Day 23 is a really fine sailer in ligher air(15<), points high (especially for a centerboard boat) and is very responsive. You will learn to love her when you get used to sailing with a heel.